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commit 194c2c74f5532e62c218adeb8e2b683119503907 upstream.
As instances may have different tracers available, we need to look at the
trace_array descriptor that shows the list of the available tracers for the
instance. But there's a race between opening the file and an admin
deleting the instance. The trace_array_get() needs to be called before
accessing the trace_array.
Cc: stable@vger.kernel.org
Fixes: 607e2ea167e56 ("tracing: Set up infrastructure to allow tracers for instances")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit 9ef16693aff8137faa21d16ffe65bb9832d24d71 upstream.
The ftrace set_ftrace_filter and set_ftrace_notrace files are specific for
an instance now. They need to take a reference to the instance otherwise
there could be a race between accessing the files and deleting the instance.
It wasn't until the :mod: caching where these file operations started
referencing the trace_array directly.
Cc: stable@vger.kernel.org
Fixes: 673feb9d76ab3 ("ftrace: Add :mod: caching infrastructure to trace_array")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit fc64e4ad80d4b72efce116f87b3174f0b7196f8e upstream.
max_latency is intended to record the maximum ever observed hardware
latency, which may occur in either part of the loop (inner/outer). So
we need to also consider the outer-loop sample when updating
max_latency.
Link: http://lkml.kernel.org/r/157073345463.17189.18124025522664682811.stgit@srivatsa-ubuntu
Fixes: e7c15cd8a113 ("tracing: Added hardware latency tracer")
Cc: stable@vger.kernel.org
Signed-off-by: Srivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit 98dc19c11470ee6048aba723d77079ad2cda8a52 upstream.
nmi_total_ts is supposed to record the total time spent in *all* NMIs
that occur on the given CPU during the (active portion of the)
sampling window. However, the code seems to be overwriting this
variable for each NMI, thereby only recording the time spent in the
most recent NMI. Fix it by accumulating the duration instead.
Link: http://lkml.kernel.org/r/157073343544.17189.13911783866738671133.stgit@srivatsa-ubuntu
Fixes: 7b2c86250122 ("tracing: Add NMI tracing in hwlat detector")
Cc: stable@vger.kernel.org
Signed-off-by: Srivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit b0f53dbc4bc4c371f38b14c391095a3bb8a0bb40 upstream.
Partially revert 16db3d3f1170 ("kernel/sysctl.c: threads-max observe
limits") because the patch is causing a regression to any workload which
needs to override the auto-tuning of the limit provided by kernel.
set_max_threads is implementing a boot time guesstimate to provide a
sensible limit of the concurrently running threads so that runaways will
not deplete all the memory. This is a good thing in general but there
are workloads which might need to increase this limit for an application
to run (reportedly WebSpher MQ is affected) and that is simply not
possible after the mentioned change. It is also very dubious to
override an admin decision by an estimation that doesn't have any direct
relation to correctness of the kernel operation.
Fix this by dropping set_max_threads from sysctl_max_threads so any
value is accepted as long as it fits into MAX_THREADS which is important
to check because allowing more threads could break internal robust futex
restriction. While at it, do not use MIN_THREADS as the lower boundary
because it is also only a heuristic for automatic estimation and admin
might have a good reason to stop new threads to be created even when
below this limit.
This became more severe when we switched x86 from 4k to 8k kernel
stacks. Starting since 6538b8ea886e ("x86_64: expand kernel stack to
16K") (3.16) we use THREAD_SIZE_ORDER = 2 and that halved the auto-tuned
value.
In the particular case
3.12
kernel.threads-max = 515561
4.4
kernel.threads-max = 200000
Neither of the two values is really insane on 32GB machine.
I am not sure we want/need to tune the max_thread value further. If
anything the tuning should be removed altogether if proven not useful in
general. But we definitely need a way to override this auto-tuning.
Link: http://lkml.kernel.org/r/20190922065801.GB18814@dhcp22.suse.cz
Fixes: 16db3d3f1170 ("kernel/sysctl.c: threads-max observe limits")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit 20bb759a66be52cf4a9ddd17fddaf509e11490cd upstream.
Calling 'panic()' on a kernel with CONFIG_PREEMPT=y can leave the
calling CPU in an infinite loop, but with interrupts and preemption
enabled. From this state, userspace can continue to be scheduled,
despite the system being "dead" as far as the kernel is concerned.
This is easily reproducible on arm64 when booting with "nosmp" on the
command line; a couple of shell scripts print out a periodic "Ping"
message whilst another triggers a crash by writing to
/proc/sysrq-trigger:
| sysrq: Trigger a crash
| Kernel panic - not syncing: sysrq triggered crash
| CPU: 0 PID: 1 Comm: init Not tainted 5.2.15 #1
| Hardware name: linux,dummy-virt (DT)
| Call trace:
| dump_backtrace+0x0/0x148
| show_stack+0x14/0x20
| dump_stack+0xa0/0xc4
| panic+0x140/0x32c
| sysrq_handle_reboot+0x0/0x20
| __handle_sysrq+0x124/0x190
| write_sysrq_trigger+0x64/0x88
| proc_reg_write+0x60/0xa8
| __vfs_write+0x18/0x40
| vfs_write+0xa4/0x1b8
| ksys_write+0x64/0xf0
| __arm64_sys_write+0x14/0x20
| el0_svc_common.constprop.0+0xb0/0x168
| el0_svc_handler+0x28/0x78
| el0_svc+0x8/0xc
| Kernel Offset: disabled
| CPU features: 0x0002,24002004
| Memory Limit: none
| ---[ end Kernel panic - not syncing: sysrq triggered crash ]---
| Ping 2!
| Ping 1!
| Ping 1!
| Ping 2!
The issue can also be triggered on x86 kernels if CONFIG_SMP=n,
otherwise local interrupts are disabled in 'smp_send_stop()'.
Disable preemption in 'panic()' before re-enabling interrupts.
Link: http://lkml.kernel.org/r/20191002123538.22609-1-will@kernel.org
Link: https://lore.kernel.org/r/BX1W47JXPMR8.58IYW53H6M5N@dragonstone
Signed-off-by: Will Deacon <will@kernel.org>
Reported-by: Xogium <contact@xogium.me>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit b9023b91dd020ad7e093baa5122b6968c48cc9e0 upstream.
When a cpu requests broadcasting, before starting the tick broadcast
hrtimer, bc_set_next() checks if the timer callback (bc_handler) is active
using hrtimer_try_to_cancel(). But hrtimer_try_to_cancel() does not provide
the required synchronization when the callback is active on other core.
The callback could have already executed tick_handle_oneshot_broadcast()
and could have also returned. But still there is a small time window where
the hrtimer_try_to_cancel() returns -1. In that case bc_set_next() returns
without doing anything, but the next_event of the tick broadcast clock
device is already set to a timeout value.
In the race condition diagram below, CPU #1 is running the timer callback
and CPU #2 is entering idle state and so calls bc_set_next().
In the worst case, the next_event will contain an expiry time, but the
hrtimer will not be started which happens when the racing callback returns
HRTIMER_NORESTART. The hrtimer might never recover if all further requests
from the CPUs to subscribe to tick broadcast have timeout greater than the
next_event of tick broadcast clock device. This leads to cascading of
failures and finally noticed as rcu stall warnings
Here is a depiction of the race condition
CPU #1 (Running timer callback) CPU #2 (Enter idle
and subscribe to
tick broadcast)
--------------------- ---------------------
__run_hrtimer() tick_broadcast_enter()
bc_handler() __tick_broadcast_oneshot_control()
tick_handle_oneshot_broadcast()
raw_spin_lock(&tick_broadcast_lock);
dev->next_event = KTIME_MAX; //wait for tick_broadcast_lock
//next_event for tick broadcast clock
set to KTIME_MAX since no other cores
subscribed to tick broadcasting
raw_spin_unlock(&tick_broadcast_lock);
if (dev->next_event == KTIME_MAX)
return HRTIMER_NORESTART
// callback function exits without
restarting the hrtimer //tick_broadcast_lock acquired
raw_spin_lock(&tick_broadcast_lock);
tick_broadcast_set_event()
clockevents_program_event()
dev->next_event = expires;
bc_set_next()
hrtimer_try_to_cancel()
//returns -1 since the timer
callback is active. Exits without
restarting the timer
cpu_base->running = NULL;
The comment that hrtimer cannot be armed from within the callback is
wrong. It is fine to start the hrtimer from within the callback. Also it is
safe to start the hrtimer from the enter/exit idle code while the broadcast
handler is active. The enter/exit idle code and the broadcast handler are
synchronized using tick_broadcast_lock. So there is no need for the
existing try to cancel logic. All this can be removed which will eliminate
the race condition as well.
Fixes: 5d1638acb9f6 ("tick: Introduce hrtimer based broadcast")
Originally-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Balasubramani Vivekanandan <balasubramani_vivekanandan@mentor.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20190926135101.12102-2-balasubramani_vivekanandan@mentor.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[PG: use 5.3.x stable version here on 5.2.x]
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit 768fb61fcc13b2acaca758275d54c09a65e2968b upstream.
BPF_PROG_TYPE_SOCK_OPS program can reenter bpf_event_output because it
can be called from atomic and non-atomic contexts since we don't have
bpf_prog_active to prevent it happen.
This patch enables 3 levels of nesting to support normal, irq and nmi
context.
We can easily reproduce the issue by running netperf crr mode with 100
flows and 10 threads from netperf client side.
Here is the whole stack dump:
[ 515.228898] WARNING: CPU: 20 PID: 14686 at kernel/trace/bpf_trace.c:549 bpf_event_output+0x1f9/0x220
[ 515.228903] CPU: 20 PID: 14686 Comm: tcp_crr Tainted: G W 4.15.0-smp-fixpanic #44
[ 515.228904] Hardware name: Intel TBG,ICH10/Ikaria_QC_1b, BIOS 1.22.0 06/04/2018
[ 515.228905] RIP: 0010:bpf_event_output+0x1f9/0x220
[ 515.228906] RSP: 0018:ffff9a57ffc03938 EFLAGS: 00010246
[ 515.228907] RAX: 0000000000000012 RBX: 0000000000000001 RCX: 0000000000000000
[ 515.228907] RDX: 0000000000000000 RSI: 0000000000000096 RDI: ffffffff836b0f80
[ 515.228908] RBP: ffff9a57ffc039c8 R08: 0000000000000004 R09: 0000000000000012
[ 515.228908] R10: ffff9a57ffc1de40 R11: 0000000000000000 R12: 0000000000000002
[ 515.228909] R13: ffff9a57e13bae00 R14: 00000000ffffffff R15: ffff9a57ffc1e2c0
[ 515.228910] FS: 00007f5a3e6ec700(0000) GS:ffff9a57ffc00000(0000) knlGS:0000000000000000
[ 515.228910] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 515.228911] CR2: 0000537082664fff CR3: 000000061fed6002 CR4: 00000000000226f0
[ 515.228911] Call Trace:
[ 515.228913] <IRQ>
[ 515.228919] [<ffffffff82c6c6cb>] bpf_sockopt_event_output+0x3b/0x50
[ 515.228923] [<ffffffff8265daee>] ? bpf_ktime_get_ns+0xe/0x10
[ 515.228927] [<ffffffff8266fda5>] ? __cgroup_bpf_run_filter_sock_ops+0x85/0x100
[ 515.228930] [<ffffffff82cf90a5>] ? tcp_init_transfer+0x125/0x150
[ 515.228933] [<ffffffff82cf9159>] ? tcp_finish_connect+0x89/0x110
[ 515.228936] [<ffffffff82cf98e4>] ? tcp_rcv_state_process+0x704/0x1010
[ 515.228939] [<ffffffff82c6e263>] ? sk_filter_trim_cap+0x53/0x2a0
[ 515.228942] [<ffffffff82d90d1f>] ? tcp_v6_inbound_md5_hash+0x6f/0x1d0
[ 515.228945] [<ffffffff82d92160>] ? tcp_v6_do_rcv+0x1c0/0x460
[ 515.228947] [<ffffffff82d93558>] ? tcp_v6_rcv+0x9f8/0xb30
[ 515.228951] [<ffffffff82d737c0>] ? ip6_route_input+0x190/0x220
[ 515.228955] [<ffffffff82d5f7ad>] ? ip6_protocol_deliver_rcu+0x6d/0x450
[ 515.228958] [<ffffffff82d60246>] ? ip6_rcv_finish+0xb6/0x170
[ 515.228961] [<ffffffff82d5fb90>] ? ip6_protocol_deliver_rcu+0x450/0x450
[ 515.228963] [<ffffffff82d60361>] ? ipv6_rcv+0x61/0xe0
[ 515.228966] [<ffffffff82d60190>] ? ipv6_list_rcv+0x330/0x330
[ 515.228969] [<ffffffff82c4976b>] ? __netif_receive_skb_one_core+0x5b/0xa0
[ 515.228972] [<ffffffff82c497d1>] ? __netif_receive_skb+0x21/0x70
[ 515.228975] [<ffffffff82c4a8d2>] ? process_backlog+0xb2/0x150
[ 515.228978] [<ffffffff82c4aadf>] ? net_rx_action+0x16f/0x410
[ 515.228982] [<ffffffff830000dd>] ? __do_softirq+0xdd/0x305
[ 515.228986] [<ffffffff8252cfdc>] ? irq_exit+0x9c/0xb0
[ 515.228989] [<ffffffff82e02de5>] ? smp_call_function_single_interrupt+0x65/0x120
[ 515.228991] [<ffffffff82e020e1>] ? call_function_single_interrupt+0x81/0x90
[ 515.228992] </IRQ>
[ 515.228996] [<ffffffff82a11ff0>] ? io_serial_in+0x20/0x20
[ 515.229000] [<ffffffff8259c040>] ? console_unlock+0x230/0x490
[ 515.229003] [<ffffffff8259cbaa>] ? vprintk_emit+0x26a/0x2a0
[ 515.229006] [<ffffffff8259cbff>] ? vprintk_default+0x1f/0x30
[ 515.229008] [<ffffffff8259d9f5>] ? vprintk_func+0x35/0x70
[ 515.229011] [<ffffffff8259d4bb>] ? printk+0x50/0x66
[ 515.229013] [<ffffffff82637637>] ? bpf_event_output+0xb7/0x220
[ 515.229016] [<ffffffff82c6c6cb>] ? bpf_sockopt_event_output+0x3b/0x50
[ 515.229019] [<ffffffff8265daee>] ? bpf_ktime_get_ns+0xe/0x10
[ 515.229023] [<ffffffff82c29e87>] ? release_sock+0x97/0xb0
[ 515.229026] [<ffffffff82ce9d6a>] ? tcp_recvmsg+0x31a/0xda0
[ 515.229029] [<ffffffff8266fda5>] ? __cgroup_bpf_run_filter_sock_ops+0x85/0x100
[ 515.229032] [<ffffffff82ce77c1>] ? tcp_set_state+0x191/0x1b0
[ 515.229035] [<ffffffff82ced10e>] ? tcp_disconnect+0x2e/0x600
[ 515.229038] [<ffffffff82cecbbb>] ? tcp_close+0x3eb/0x460
[ 515.229040] [<ffffffff82d21082>] ? inet_release+0x42/0x70
[ 515.229043] [<ffffffff82d58809>] ? inet6_release+0x39/0x50
[ 515.229046] [<ffffffff82c1f32d>] ? __sock_release+0x4d/0xd0
[ 515.229049] [<ffffffff82c1f3e5>] ? sock_close+0x15/0x20
[ 515.229052] [<ffffffff8273b517>] ? __fput+0xe7/0x1f0
[ 515.229055] [<ffffffff8273b66e>] ? ____fput+0xe/0x10
[ 515.229058] [<ffffffff82547bf2>] ? task_work_run+0x82/0xb0
[ 515.229061] [<ffffffff824086df>] ? exit_to_usermode_loop+0x7e/0x11f
[ 515.229064] [<ffffffff82408171>] ? do_syscall_64+0x111/0x130
[ 515.229067] [<ffffffff82e0007c>] ? entry_SYSCALL_64_after_hwframe+0x3d/0xa2
Fixes: a5a3a828cd00 ("bpf: add perf event notificaton support for sock_ops")
Signed-off-by: Allan Zhang <allanzhang@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20190925234312.94063-2-allanzhang@google.com
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit 0f74914071ab7e7b78731ed62bf350e3a344e0a5 upstream.
When building with W=1, gcc properly complains that there's no prototypes:
CC kernel/elfcore.o
kernel/elfcore.c:7:17: warning: no previous prototype for 'elf_core_extra_phdrs' [-Wmissing-prototypes]
7 | Elf_Half __weak elf_core_extra_phdrs(void)
| ^~~~~~~~~~~~~~~~~~~~
kernel/elfcore.c:12:12: warning: no previous prototype for 'elf_core_write_extra_phdrs' [-Wmissing-prototypes]
12 | int __weak elf_core_write_extra_phdrs(struct coredump_params *cprm, loff_t offset)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
kernel/elfcore.c:17:12: warning: no previous prototype for 'elf_core_write_extra_data' [-Wmissing-prototypes]
17 | int __weak elf_core_write_extra_data(struct coredump_params *cprm)
| ^~~~~~~~~~~~~~~~~~~~~~~~~
kernel/elfcore.c:22:15: warning: no previous prototype for 'elf_core_extra_data_size' [-Wmissing-prototypes]
22 | size_t __weak elf_core_extra_data_size(void)
| ^~~~~~~~~~~~~~~~~~~~~~~~
Provide the include file so gcc is happy, and we don't have potential code drift
Link: http://lkml.kernel.org/r/29875.1565224705@turing-police
Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit 714e501e16cd473538b609b3e351b2cc9f7f09ed upstream.
An oops can be triggered in the scheduler when running qemu on arm64:
Unable to handle kernel paging request at virtual address ffff000008effe40
Internal error: Oops: 96000007 [#1] SMP
Process migration/0 (pid: 12, stack limit = 0x00000000084e3736)
pstate: 20000085 (nzCv daIf -PAN -UAO)
pc : __ll_sc___cmpxchg_case_acq_4+0x4/0x20
lr : move_queued_task.isra.21+0x124/0x298
...
Call trace:
__ll_sc___cmpxchg_case_acq_4+0x4/0x20
__migrate_task+0xc8/0xe0
migration_cpu_stop+0x170/0x180
cpu_stopper_thread+0xec/0x178
smpboot_thread_fn+0x1ac/0x1e8
kthread+0x134/0x138
ret_from_fork+0x10/0x18
__set_cpus_allowed_ptr() will choose an active dest_cpu in affinity mask to
migrage the process if process is not currently running on any one of the
CPUs specified in affinity mask. __set_cpus_allowed_ptr() will choose an
invalid dest_cpu (dest_cpu >= nr_cpu_ids, 1024 in my virtual machine) if
CPUS in an affinity mask are deactived by cpu_down after cpumask_intersects
check. cpumask_test_cpu() of dest_cpu afterwards is overflown and may pass if
corresponding bit is coincidentally set. As a consequence, kernel will
access an invalid rq address associate with the invalid CPU in
migration_cpu_stop->__migrate_task->move_queued_task and the Oops occurs.
The reproduce the crash:
1) A process repeatedly binds itself to cpu0 and cpu1 in turn by calling
sched_setaffinity.
2) A shell script repeatedly does "echo 0 > /sys/devices/system/cpu/cpu1/online"
and "echo 1 > /sys/devices/system/cpu/cpu1/online" in turn.
3) Oops appears if the invalid CPU is set in memory after tested cpumask.
Signed-off-by: KeMeng Shi <shikemeng@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/1568616808-16808-1-git-send-email-shikemeng@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit fc0d77387cb5ae883fd774fc559e056a8dde024c upstream.
Fix a logic flaw in the way membarrier_register_private_expedited()
handles ready state checks for private expedited sync core and private
expedited registrations.
If a private expedited membarrier registration is first performed, and
then a private expedited sync_core registration is performed, the ready
state check will skip the second registration when it really should not.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190919173705.2181-2-mathieu.desnoyers@efficios.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit 89340d0935c9296c7b8222b6eab30e67cb57ab82 upstream.
This patch reverts commit 75437bb304b20 (locking/pvqspinlock: Don't
wait if vCPU is preempted). A large performance regression was caused
by this commit. on over-subscription scenarios.
The test was run on a Xeon Skylake box, 2 sockets, 40 cores, 80 threads,
with three VMs of 80 vCPUs each. The score of ebizzy -M is reduced from
13000-14000 records/s to 1700-1800 records/s:
Host Guest score
vanilla w/o kvm optimizations upstream 1700-1800 records/s
vanilla w/o kvm optimizations revert 13000-14000 records/s
vanilla w/ kvm optimizations upstream 4500-5000 records/s
vanilla w/ kvm optimizations revert 14000-15500 records/s
Exit from aggressive wait-early mechanism can result in premature yield
and extra scheduling latency.
Actually, only 6% of wait_early events are caused by vcpu_is_preempted()
being true. However, when one vCPU voluntarily releases its vCPU, all
the subsequently waiters in the queue will do the same and the cascading
effect leads to bad performance.
kvm optimizations:
[1] commit d73eb57b80b (KVM: Boost vCPUs that are delivering interrupts)
[2] commit 266e85a5ec9 (KVM: X86: Boost queue head vCPU to mitigate lock waiter preemption)
Tested-by: loobinliu@tencent.com
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: loobinliu@tencent.com
Cc: stable@vger.kernel.org
Fixes: 75437bb304b20 (locking/pvqspinlock: Don't wait if vCPU is preempted)
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit e430d802d6a3aaf61bd3ed03d9404888a29b9bf9 upstream.
The timer delayed for more than 3 seconds warning was triggered during
testing.
Workqueue: events_unbound sched_tick_remote
RIP: 0010:sched_tick_remote+0xee/0x100
...
Call Trace:
process_one_work+0x18c/0x3a0
worker_thread+0x30/0x380
kthread+0x113/0x130
ret_from_fork+0x22/0x40
The reason is that the code in collect_expired_timers() uses jiffies
unprotected:
if (next_event > jiffies)
base->clk = jiffies;
As the compiler is allowed to reload the value base->clk can advance
between the check and the store and in the worst case advance farther than
next event. That causes the timer expiry to be delayed until the wheel
pointer wraps around.
Convert the code to use READ_ONCE()
Fixes: 236968383cf5 ("timers: Optimize collect_expired_timers() for NOHZ")
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Signed-off-by: Liang ZhiCheng <liangzhicheng@baidu.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/1568894687-14499-1-git-send-email-lirongqing@baidu.com
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit 17f8607a1658a8e70415eef67909f990d13017b5 upstream.
Original changelog from Steve Rostedt (except last sentence which
explains the problem, and the Fixes: tag):
I performed a three way histogram with the following commands:
echo 'irq_lat u64 lat pid_t pid' > synthetic_events
echo 'wake_lat u64 lat u64 irqlat pid_t pid' >> synthetic_events
echo 'hist:keys=common_pid:irqts=common_timestamp.usecs if function == 0xffffffff81200580' > events/timer/hrtimer_start/trigger
echo 'hist:keys=common_pid:lat=common_timestamp.usecs-$irqts:onmatch(timer.hrtimer_start).irq_lat($lat,pid) if common_flags & 1' > events/sched/sched_waking/trigger
echo 'hist:keys=pid:wakets=common_timestamp.usecs,irqlat=lat' > events/synthetic/irq_lat/trigger
echo 'hist:keys=next_pid:lat=common_timestamp.usecs-$wakets,irqlat=$irqlat:onmatch(synthetic.irq_lat).wake_lat($lat,$irqlat,next_pid)' > events/sched/sched_switch/trigger
echo 1 > events/synthetic/wake_lat/enable
Basically I wanted to see:
hrtimer_start (calling function tick_sched_timer)
Note:
# grep tick_sched_timer /proc/kallsyms
ffffffff81200580 t tick_sched_timer
And save the time of that, and then record sched_waking if it is called
in interrupt context and with the same pid as the hrtimer_start, it
will record the latency between that and the waking event.
I then look at when the task that is woken is scheduled in, and record
the latency between the wakeup and the task running.
At the end, the wake_lat synthetic event will show the wakeup to
scheduled latency, as well as the irq latency in from hritmer_start to
the wakeup. The problem is that I found this:
<idle>-0 [007] d... 190.485261: wake_lat: lat=27 irqlat=190485230 pid=698
<idle>-0 [005] d... 190.485283: wake_lat: lat=40 irqlat=190485239 pid=10
<idle>-0 [002] d... 190.488327: wake_lat: lat=56 irqlat=190488266 pid=335
<idle>-0 [005] d... 190.489330: wake_lat: lat=64 irqlat=190489262 pid=10
<idle>-0 [003] d... 190.490312: wake_lat: lat=43 irqlat=190490265 pid=77
<idle>-0 [005] d... 190.493322: wake_lat: lat=54 irqlat=190493262 pid=10
<idle>-0 [005] d... 190.497305: wake_lat: lat=35 irqlat=190497267 pid=10
<idle>-0 [005] d... 190.501319: wake_lat: lat=50 irqlat=190501264 pid=10
The irqlat seemed quite large! Investigating this further, if I had
enabled the irq_lat synthetic event, I noticed this:
<idle>-0 [002] d.s. 249.429308: irq_lat: lat=164968 pid=335
<idle>-0 [002] d... 249.429369: wake_lat: lat=55 irqlat=249429308 pid=335
Notice that the timestamp of the irq_lat "249.429308" is awfully
similar to the reported irqlat variable. In fact, all instances were
like this. It appeared that:
irqlat=$irqlat
Wasn't assigning the old $irqlat to the new irqlat variable, but
instead was assigning the $irqts to it.
The issue is that assigning the old $irqlat to the new irqlat variable
creates a variable reference alias, but the alias creation code
forgets to make sure the alias uses the same var_ref_idx to access the
reference.
Link: http://lkml.kernel.org/r/1567375321.5282.12.camel@kernel.org
Cc: Linux Trace Devel <linux-trace-devel@vger.kernel.org>
Cc: linux-rt-users <linux-rt-users@vger.kernel.org>
Cc: stable@vger.kernel.org
Fixes: 7e8b88a30b085 ("tracing: Add hist trigger support for variable reference aliases")
Reported-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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commit 7c3a6aedcd6aae0a32a527e68669f7dd667492d1 upstream.
syzbot found that a thread can stall for minutes inside kexec_load() after
that thread was killed by SIGKILL [1]. It turned out that the reproducer
was trying to allocate 2408MB of memory using kimage_alloc_page() from
kimage_load_normal_segment(). Let's check for SIGKILL before doing memory
allocation.
[1] https://syzkaller.appspot.com/bug?id=a0e3436829698d5824231251fad9d8e998f94f5e
Link: http://lkml.kernel.org/r/993c9185-d324-2640-d061-bed2dd18b1f7@I-love.SAKURA.ne.jp
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: syzbot <syzbot+8ab2d0f39fb79fe6ca40@syzkaller.appspotmail.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 4ff96fb52c6964ad42e0a878be8f86a2e8052ddd ]
klp_module_coming() is called for every module appearing in the system.
It sets obj->mod to a patched module for klp_object obj. Unfortunately
it leaves it set even if an error happens later in the function and the
patched module is not allowed to be loaded.
klp_is_object_loaded() uses obj->mod variable and could currently give a
wrong return value. The bug is probably harmless as of now.
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit f18ddc13af981ce3c7b7f26925f099e7c6929aba upstream.
ENOTSUPP is not supposed to be returned to userspace. This was found on an
OpenPower machine, where the RTC does not support set_alarm.
On that system, a clock_nanosleep(CLOCK_REALTIME_ALARM, ...) results in
"524 Unknown error 524"
Replace it with EOPNOTSUPP which results in the expected "95 Operation not
supported" error.
Fixes: 1c6b39ad3f01 (alarmtimers: Return -ENOTSUPP if no RTC device is present)
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20190903171802.28314-1-cascardo@canonical.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 130d9c331bc59a8733b47c58ef197a2b1fa3ed43 ]
A rather embarrasing mistake had us call sched_setscheduler() before
initializing the parameters passed to it.
Fixes: 1a763fd7c633 ("rcu/tree: Call setschedule() gp ktread to SCHED_FIFO outside of atomic region")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit c9dccacfccc72c32692eedff4a27a4b0833a2afd upstream.
kmsg_dump_get_buffer() is supposed to select all the youngest log
messages which fit into the provided buffer. It determines the correct
start index by using msg_print_text() with a NULL buffer to calculate
the size of each entry. However, when performing the actual writes,
msg_print_text() only writes the entry to the buffer if the written len
is lesser than the size of the buffer. So if the lengths of the
selected youngest log messages happen to precisely fill up the provided
buffer, the last log message is not included.
We don't want to modify msg_print_text() to fill up the buffer and start
returning a length which is equal to the size of the buffer, since
callers of its other users, such as kmsg_dump_get_line(), depend upon
the current behaviour.
Instead, fix kmsg_dump_get_buffer() to compensate for this.
For example, with the following two final prints:
[ 6.427502] AAAAAAAAAAAAA
[ 6.427769] BBBBBBBB12345
A dump of a 64-byte buffer filled by kmsg_dump_get_buffer(), before this
patch:
00000000: 3c 30 3e 5b 20 20 20 20 36 2e 35 32 32 31 39 37 <0>[ 6.522197
00000010: 5d 20 41 41 41 41 41 41 41 41 41 41 41 41 41 0a ] AAAAAAAAAAAAA.
00000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
After this patch:
00000000: 3c 30 3e 5b 20 20 20 20 36 2e 34 35 36 36 37 38 <0>[ 6.456678
00000010: 5d 20 42 42 42 42 42 42 42 42 31 32 33 34 35 0a ] BBBBBBBB12345.
00000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
Link: http://lkml.kernel.org/r/20190711142937.4083-1-vincent.whitchurch@axis.com
Fixes: e2ae715d66bf4bec ("kmsg - kmsg_dump() use iterator to receive log buffer content")
To: rostedt@goodmis.org
Cc: linux-kernel@vger.kernel.org
Cc: <stable@vger.kernel.org> # v3.5+
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 4adcdcea717cb2d8436bef00dd689aa5bc76f11b ]
When passing a equal or more then 32 bytes long string to psi_write(),
psi_write() copies 31 bytes to its buf and overwrites buf[30]
with '\0'. Which makes the input string 1 byte shorter than
it should be.
Fix it by copying sizeof(buf) bytes when nbytes >= sizeof(buf).
This does not cause problems in normal use case like:
"some 500000 10000000" or "full 500000 10000000" because they
are less than 32 bytes in length.
/* assuming nbytes == 35 */
char buf[32];
buf_size = min(nbytes, (sizeof(buf) - 1)); /* buf_size = 31 */
if (copy_from_user(buf, user_buf, buf_size))
return -EFAULT;
buf[buf_size - 1] = '\0'; /* buf[30] = '\0' */
Before:
%cd /proc/pressure/
%echo "123456789|123456789|123456789|1234" > memory
[ 22.473497] nbytes=35,buf_size=31
[ 22.473775] 123456789|123456789|123456789| (print 30 chars)
%sh: write error: Invalid argument
%echo "123456789|123456789|123456789|1" > memory
[ 64.916162] nbytes=32,buf_size=31
[ 64.916331] 123456789|123456789|123456789| (print 30 chars)
%sh: write error: Invalid argument
After:
%cd /proc/pressure/
%echo "123456789|123456789|123456789|1234" > memory
[ 254.837863] nbytes=35,buf_size=32
[ 254.838541] 123456789|123456789|123456789|1 (print 31 chars)
%sh: write error: Invalid argument
%echo "123456789|123456789|123456789|1" > memory
[ 9965.714935] nbytes=32,buf_size=32
[ 9965.715096] 123456789|123456789|123456789|1 (print 31 chars)
%sh: write error: Invalid argument
Also remove the superfluous parentheses.
Signed-off-by: Miles Chen <miles.chen@mediatek.com>
Cc: <linux-mediatek@lists.infradead.org>
Cc: <wsd_upstream@mediatek.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190912103452.13281-1-miles.chen@mediatek.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit e336b4027775cb458dc713745e526fa1a1996b2a ]
Since BUG() and WARN() may use a trap (e.g. UD2 on x86) to
get the address where the BUG() has occurred, kprobes can not
do single-step out-of-line that instruction. So prohibit
probing on such address.
Without this fix, if someone put a kprobe on WARN(), the
kernel will crash with invalid opcode error instead of
outputing warning message, because kernel can not find
correct bug address.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S . Miller <davem@davemloft.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Naveen N . Rao <naveen.n.rao@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/156750890133.19112.3393666300746167111.stgit@devnote2
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 77c84dd1881d0f0176cb678d770bfbda26c54390 ]
Fast switching path only emits an event for the CPU of interest, whereas the
regular path emits an event for all the CPUs that had their frequency changed,
i.e. all the CPUs sharing the same policy.
With the current behavior, looking at cpu_frequency event for a given CPU that
is using the fast switching path will not give the correct frequency signal.
Signed-off-by: Douglas RAILLARD <douglas.raillard@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 692117c1f7a6770ed41dd8f277cd9fed1dfb16f1 ]
Warning when p == NULL and then proceeding and dereferencing p does not
make any sense as the kernel will crash with a NULL pointer dereference
right away.
Bailing out when p == NULL and returning an error code does not cure the
underlying problem which caused p to be NULL. Though it might allow to
do proper debugging.
Same applies to the clock id check in set_process_cpu_timer().
Clean them up and make them return without trying to do further damage.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190819143801.846497772@linutronix.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit e78a7614f3876ac649b3df608789cb6ef74d0480 ]
Scheduling-clock interrupts can arrive late in the CPU-offline process,
after idle entry and the subsequent call to cpuhp_report_idle_dead().
Once execution passes the call to rcu_report_dead(), RCU is ignoring
the CPU, which results in lockdep complaints when the interrupt handler
uses RCU:
------------------------------------------------------------------------
=============================
WARNING: suspicious RCU usage
5.2.0-rc1+ #681 Not tainted
-----------------------------
kernel/sched/fair.c:9542 suspicious rcu_dereference_check() usage!
other info that might help us debug this:
RCU used illegally from offline CPU!
rcu_scheduler_active = 2, debug_locks = 1
no locks held by swapper/5/0.
stack backtrace:
CPU: 5 PID: 0 Comm: swapper/5 Not tainted 5.2.0-rc1+ #681
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS Bochs 01/01/2011
Call Trace:
<IRQ>
dump_stack+0x5e/0x8b
trigger_load_balance+0xa8/0x390
? tick_sched_do_timer+0x60/0x60
update_process_times+0x3b/0x50
tick_sched_handle+0x2f/0x40
tick_sched_timer+0x32/0x70
__hrtimer_run_queues+0xd3/0x3b0
hrtimer_interrupt+0x11d/0x270
? sched_clock_local+0xc/0x74
smp_apic_timer_interrupt+0x79/0x200
apic_timer_interrupt+0xf/0x20
</IRQ>
RIP: 0010:delay_tsc+0x22/0x50
Code: ff 0f 1f 80 00 00 00 00 65 44 8b 05 18 a7 11 48 0f ae e8 0f 31 48 89 d6 48 c1 e6 20 48 09 c6 eb 0e f3 90 65 8b 05 fe a6 11 48 <41> 39 c0 75 18 0f ae e8 0f 31 48 c1 e2 20 48 09 c2 48 89 d0 48 29
RSP: 0000:ffff8f92c0157ed0 EFLAGS: 00000212 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000005 RBX: ffff8c861f356400 RCX: ffff8f92c0157e64
RDX: 000000321214c8cc RSI: 00000032120daa7f RDI: 0000000000260f15
RBP: 0000000000000005 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000000 R14: ffff8c861ee18000 R15: ffff8c861ee18000
cpuhp_report_idle_dead+0x31/0x60
do_idle+0x1d5/0x200
? _raw_spin_unlock_irqrestore+0x2d/0x40
cpu_startup_entry+0x14/0x20
start_secondary+0x151/0x170
secondary_startup_64+0xa4/0xb0
------------------------------------------------------------------------
This happens rarely, but can be forced by happen more often by
placing delays in cpuhp_report_idle_dead() following the call to
rcu_report_dead(). With this in place, the following rcutorture
scenario reproduces the problem within a few minutes:
tools/testing/selftests/rcutorture/bin/kvm.sh --cpus 8 --duration 5 --kconfig "CONFIG_DEBUG_LOCK_ALLOC=y CONFIG_PROVE_LOCKING=y" --configs "TREE04"
This commit uses the crude but effective expedient of moving the disabling
of interrupts within the idle loop to precede the cpu_is_offline()
check. It also invokes tick_nohz_idle_stop_tick() instead of
tick_nohz_idle_stop_tick_protected() to shut off the scheduling-clock
interrupt.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
[ paulmck: Revert tick_nohz_idle_stop_tick_protected() removal, new callers. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit a46d14eca7b75fffe35603aa8b81df654353d80f ]
Enabling WARN_DOUBLE_CLOCK in /sys/kernel/debug/sched_features causes
warning to fire in update_rq_clock. This seems to be caused by onlining
a new fair sched group not using the rq lock wrappers.
[] rq->clock_update_flags & RQCF_UPDATED
[] WARNING: CPU: 5 PID: 54385 at kernel/sched/core.c:210 update_rq_clock+0xec/0x150
[] Call Trace:
[] online_fair_sched_group+0x53/0x100
[] cpu_cgroup_css_online+0x16/0x20
[] online_css+0x1c/0x60
[] cgroup_apply_control_enable+0x231/0x3b0
[] cgroup_mkdir+0x41b/0x530
[] kernfs_iop_mkdir+0x61/0xa0
[] vfs_mkdir+0x108/0x1a0
[] do_mkdirat+0x77/0xe0
[] do_syscall_64+0x55/0x1d0
[] entry_SYSCALL_64_after_hwframe+0x44/0xa9
Using the wrappers in online_fair_sched_group instead of the raw locking
removes this warning.
[ tglx: Use rq_*lock_irq() ]
Signed-off-by: Phil Auld <pauld@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Ingo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20190801133749.11033-1-pauld@redhat.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 1a763fd7c6335e3122c1cc09576ef6c99ada4267 ]
sched_setscheduler() needs to acquire cpuset_rwsem, but it is currently
called from an invalid (atomic) context by rcu_spawn_gp_kthread().
Fix that by simply moving sched_setscheduler_nocheck() call outside of
the atomic region, as it doesn't actually require to be guarded by
rcu_node lock.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: bristot@redhat.com
Cc: claudio@evidence.eu.com
Cc: lizefan@huawei.com
Cc: longman@redhat.com
Cc: luca.abeni@santannapisa.it
Cc: mathieu.poirier@linaro.org
Cc: rostedt@goodmis.org
Cc: tj@kernel.org
Cc: tommaso.cucinotta@santannapisa.it
Link: https://lkml.kernel.org/r/20190719140000.31694-8-juri.lelli@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 59d06cea1198d665ba11f7e8c5f45b00ff2e4812 ]
If a task happens to be throttled while the CPU it was running on gets
hotplugged off, the bandwidth associated with the task is not correctly
migrated with it when the replenishment timer fires (offline_migration).
Fix things up, for this_bw, running_bw and total_bw, when replenishment
timer fires and task is migrated (dl_task_offline_migration()).
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: bristot@redhat.com
Cc: claudio@evidence.eu.com
Cc: lizefan@huawei.com
Cc: longman@redhat.com
Cc: luca.abeni@santannapisa.it
Cc: mathieu.poirier@linaro.org
Cc: rostedt@goodmis.org
Cc: tj@kernel.org
Cc: tommaso.cucinotta@santannapisa.it
Link: https://lkml.kernel.org/r/20190719140000.31694-5-juri.lelli@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit a07db5c0865799ebed1f88be0df50c581fb65029 ]
On !CONFIG_RT_GROUP_SCHED configurations it is currently not possible to
move RT tasks between cgroups to which CPU controller has been attached;
but it is oddly possible to first move tasks around and then make them
RT (setschedule to FIFO/RR).
E.g.:
# mkdir /sys/fs/cgroup/cpu,cpuacct/group1
# chrt -fp 10 $$
# echo $$ > /sys/fs/cgroup/cpu,cpuacct/group1/tasks
bash: echo: write error: Invalid argument
# chrt -op 0 $$
# echo $$ > /sys/fs/cgroup/cpu,cpuacct/group1/tasks
# chrt -fp 10 $$
# cat /sys/fs/cgroup/cpu,cpuacct/group1/tasks
2345
2598
# chrt -p 2345
pid 2345's current scheduling policy: SCHED_FIFO
pid 2345's current scheduling priority: 10
Also, as Michal noted, it is currently not possible to enable CPU
controller on unified hierarchy with !CONFIG_RT_GROUP_SCHED (if there
are any kernel RT threads in root cgroup, they can't be migrated to the
newly created CPU controller's root in cgroup_update_dfl_csses()).
Existing code comes with a comment saying the "we don't support RT-tasks
being in separate groups". Such comment is however stale and belongs to
pre-RT_GROUP_SCHED times. Also, it doesn't make much sense for
!RT_GROUP_ SCHED configurations, since checks related to RT bandwidth
are not performed at all in these cases.
Make moving RT tasks between CPU controller groups viable by removing
special case check for RT (and DEADLINE) tasks.
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: lizefan@huawei.com
Cc: longman@redhat.com
Cc: luca.abeni@santannapisa.it
Cc: rostedt@goodmis.org
Link: https://lkml.kernel.org/r/20190719063455.27328-1-juri.lelli@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit f6cad8df6b30a5d2bbbd2e698f74b4cafb9fb82b ]
The load_balance() has a dedicated mecanism to detect when an imbalance
is due to CPU affinity and must be handled at parent level. In this case,
the imbalance field of the parent's sched_group is set.
The description of sg_imbalanced() gives a typical example of two groups
of 4 CPUs each and 4 tasks each with a cpumask covering 1 CPU of the first
group and 3 CPUs of the second group. Something like:
{ 0 1 2 3 } { 4 5 6 7 }
* * * *
But the load_balance fails to fix this UC on my octo cores system
made of 2 clusters of quad cores.
Whereas the load_balance is able to detect that the imbalanced is due to
CPU affinity, it fails to fix it because the imbalance field is cleared
before letting parent level a chance to run. In fact, when the imbalance is
detected, the load_balance reruns without the CPU with pinned tasks. But
there is no other running tasks in the situation described above and
everything looks balanced this time so the imbalance field is immediately
cleared.
The imbalance field should not be cleared if there is no other task to move
when the imbalance is detected.
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/1561996022-28829-1-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 84ec3a0787086fcd25f284f59b3aa01fd6fc0a5d ]
time/tick-broadcast: Fix tick_broadcast_offline() lockdep complaint
The TASKS03 and TREE04 rcutorture scenarios produce the following
lockdep complaint:
WARNING: inconsistent lock state
5.2.0-rc1+ #513 Not tainted
--------------------------------
inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
migration/1/14 [HC0[0]:SC0[0]:HE1:SE1] takes:
(____ptrval____) (tick_broadcast_lock){?...}, at: tick_broadcast_offline+0xf/0x70
{IN-HARDIRQ-W} state was registered at:
lock_acquire+0xb0/0x1c0
_raw_spin_lock_irqsave+0x3c/0x50
tick_broadcast_switch_to_oneshot+0xd/0x40
tick_switch_to_oneshot+0x4f/0xd0
hrtimer_run_queues+0xf3/0x130
run_local_timers+0x1c/0x50
update_process_times+0x1c/0x50
tick_periodic+0x26/0xc0
tick_handle_periodic+0x1a/0x60
smp_apic_timer_interrupt+0x80/0x2a0
apic_timer_interrupt+0xf/0x20
_raw_spin_unlock_irqrestore+0x4e/0x60
rcu_nocb_gp_kthread+0x15d/0x590
kthread+0xf3/0x130
ret_from_fork+0x3a/0x50
irq event stamp: 171
hardirqs last enabled at (171): [<ffffffff8a201a37>] trace_hardirqs_on_thunk+0x1a/0x1c
hardirqs last disabled at (170): [<ffffffff8a201a53>] trace_hardirqs_off_thunk+0x1a/0x1c
softirqs last enabled at (0): [<ffffffff8a264ee0>] copy_process.part.56+0x650/0x1cb0
softirqs last disabled at (0): [<0000000000000000>] 0x0
[...]
To reproduce, run the following rcutorture test:
$ tools/testing/selftests/rcutorture/bin/kvm.sh --duration 5 --kconfig "CONFIG_DEBUG_LOCK_ALLOC=y CONFIG_PROVE_LOCKING=y" --configs "TASKS03 TREE04"
It turns out that tick_broadcast_offline() was an innocent bystander.
After all, interrupts are supposed to be disabled throughout
take_cpu_down(), and therefore should have been disabled upon entry to
tick_offline_cpu() and thus to tick_broadcast_offline(). This suggests
that one of the CPU-hotplug notifiers was incorrectly enabling interrupts,
and leaving them enabled on return.
Some debugging code showed that the culprit was sched_cpu_dying().
It had irqs enabled after return from sched_tick_stop(). Which in turn
had irqs enabled after return from cancel_delayed_work_sync(). Which is a
wrapper around __cancel_work_timer(). Which can sleep in the case where
something else is concurrently trying to cancel the same delayed work,
and as Thomas Gleixner pointed out on IRC, sleeping is a decidedly bad
idea when you are invoked from take_cpu_down(), regardless of the state
you leave interrupts in upon return.
Code inspection located no reason why the delayed work absolutely
needed to be canceled from sched_tick_stop(): The work is not
bound to the outgoing CPU by design, given that the whole point is
to collect statistics without disturbing the outgoing CPU.
This commit therefore simply drops the cancel_delayed_work_sync() from
sched_tick_stop(). Instead, a new ->state field is added to the tick_work
structure so that the delayed-work handler function sched_tick_remote()
can avoid reposting itself. A cpu_is_offline() check is also added to
sched_tick_remote() to avoid mucking with the state of an offlined CPU
(though it does appear safe to do so). The sched_tick_start() and
sched_tick_stop() functions also update ->state, and sched_tick_start()
also schedules the delayed work if ->state indicates that it is not
already in flight.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
[ paulmck: Apply Peter Zijlstra and Frederic Weisbecker atomics feedback. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190625165238.GJ26519@linux.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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first symbol
[ Upstream commit 2a1a3fa0f29270583f0e6e3100d609e09697add1 ]
An arm64 kernel configured with
CONFIG_KPROBES=y
CONFIG_KALLSYMS=y
# CONFIG_KALLSYMS_ALL is not set
CONFIG_KALLSYMS_BASE_RELATIVE=y
reports the following kprobe failure:
[ 0.032677] kprobes: failed to populate blacklist: -22
[ 0.033376] Please take care of using kprobes.
It appears that kprobe fails to retrieve the symbol at address
0xffff000010081000, despite this symbol being in System.map:
ffff000010081000 T __exception_text_start
This symbol is part of the first group of aliases in the
kallsyms_offsets array (symbol names generated using ugly hacks in
scripts/kallsyms.c):
kallsyms_offsets:
.long 0x1000 // do_undefinstr
.long 0x1000 // efi_header_end
.long 0x1000 // _stext
.long 0x1000 // __exception_text_start
.long 0x12b0 // do_cp15instr
Looking at the implementation of get_symbol_pos(), it returns the
lowest index for aliasing symbols. In this case, it return 0.
But kallsyms_lookup_size_offset() considers 0 as a failure, which
is obviously wrong (there is definitely a valid symbol living there).
In turn, the kprobe blacklisting stops abruptly, hence the original
error.
A CONFIG_KALLSYMS_ALL kernel wouldn't fail as there is always
some random symbols at the beginning of this array, which are never
looked up via kallsyms_lookup_size_offset.
Fix it by considering that get_symbol_pos() is always successful
(which is consistent with the other uses of this function).
Fixes: ffc5089196446 ("[PATCH] Create kallsyms_lookup_size_offset()")
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 38f054d549a869f22a02224cd276a27bf14b6171 upstream.
Some arches (e.g., arm64, x86) have moved towards non-executable
module_alloc() allocations for security hardening reasons. That means
that the module loader will need to set the text section of a module to
executable, regardless of whether or not CONFIG_STRICT_MODULE_RWX is set.
When CONFIG_STRICT_MODULE_RWX=y, module section allocations are always
page-aligned to handle memory rwx permissions. On some arches with
CONFIG_STRICT_MODULE_RWX=n however, when setting the module text to
executable, the BUG_ON() in frob_text() gets triggered since module
section allocations are not page-aligned when CONFIG_STRICT_MODULE_RWX=n.
Since the set_memory_* API works with pages, and since we need to call
set_memory_x() regardless of whether CONFIG_STRICT_MODULE_RWX is set, we
might as well page-align all module section allocations for ease of
managing rwx permissions of module sections (text, rodata, etc).
Fixes: 2eef1399a866 ("modules: fix BUG when load module with rodata=n")
Reported-by: Martin Kaiser <lists@kaiser.cx>
Reported-by: Bartosz Golaszewski <brgl@bgdev.pl>
Tested-by: David Lechner <david@lechnology.com>
Tested-by: Martin Kaiser <martin@kaiser.cx>
Tested-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 93651f80dcb616b8c9115cdafc8e57a781af22d0 upstream.
If CONFIG_ARCH_HAS_STRICT_MODULE_RWX is not defined,
we need stub for module_enable_nx() and module_enable_x().
If CONFIG_ARCH_HAS_STRICT_MODULE_RWX is defined, but
CONFIG_STRICT_MODULE_RWX is disabled, we need stub for
module_enable_nx.
Move frob_text() outside of the CONFIG_STRICT_MODULE_RWX,
because it is needed anyway.
Fixes: 2eef1399a866 ("modules: fix BUG when load module with rodata=n")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 2eef1399a866c57687962e15142b141a4f8e7862 upstream.
When loading a module with rodata=n, it causes an executing
NX-protected page BUG.
[ 32.379191] kernel tried to execute NX-protected page - exploit attempt? (uid: 0)
[ 32.382917] BUG: unable to handle page fault for address: ffffffffc0005000
[ 32.385947] #PF: supervisor instruction fetch in kernel mode
[ 32.387662] #PF: error_code(0x0011) - permissions violation
[ 32.389352] PGD 240c067 P4D 240c067 PUD 240e067 PMD 421a52067 PTE 8000000421a53063
[ 32.391396] Oops: 0011 [#1] SMP PTI
[ 32.392478] CPU: 7 PID: 2697 Comm: insmod Tainted: G O 5.2.0-rc5+ #202
[ 32.394588] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014
[ 32.398157] RIP: 0010:ko_test_init+0x0/0x1000 [ko_test]
[ 32.399662] Code: Bad RIP value.
[ 32.400621] RSP: 0018:ffffc900029f3ca8 EFLAGS: 00010246
[ 32.402171] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[ 32.404332] RDX: 00000000000004c7 RSI: 0000000000000cc0 RDI: ffffffffc0005000
[ 32.406347] RBP: ffffffffc0005000 R08: ffff88842fbebc40 R09: ffffffff810ede4a
[ 32.408392] R10: ffffea00108e3480 R11: 0000000000000000 R12: ffff88842bee21a0
[ 32.410472] R13: 0000000000000001 R14: 0000000000000001 R15: ffffc900029f3e78
[ 32.412609] FS: 00007fb4f0c0a700(0000) GS:ffff88842fbc0000(0000) knlGS:0000000000000000
[ 32.414722] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 32.416290] CR2: ffffffffc0004fd6 CR3: 0000000421a90004 CR4: 0000000000020ee0
[ 32.418471] Call Trace:
[ 32.419136] do_one_initcall+0x41/0x1df
[ 32.420199] ? _cond_resched+0x10/0x40
[ 32.421433] ? kmem_cache_alloc_trace+0x36/0x160
[ 32.422827] do_init_module+0x56/0x1f7
[ 32.423946] load_module+0x1e67/0x2580
[ 32.424947] ? __alloc_pages_nodemask+0x150/0x2c0
[ 32.426413] ? map_vm_area+0x2d/0x40
[ 32.427530] ? __vmalloc_node_range+0x1ef/0x260
[ 32.428850] ? __do_sys_init_module+0x135/0x170
[ 32.430060] ? _cond_resched+0x10/0x40
[ 32.431249] __do_sys_init_module+0x135/0x170
[ 32.432547] do_syscall_64+0x43/0x120
[ 32.433853] entry_SYSCALL_64_after_hwframe+0x44/0xa9
Because if rodata=n, set_memory_x() can't be called, fix this by
calling set_memory_x in complete_formation();
Fixes: f2c65fb3221a ("x86/modules: Avoid breaking W^X while loading modules")
Suggested-by: Jian Cheng <cj.chengjian@huawei.com>
Reviewed-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit bc6f2a757d525e001268c3658bd88822e768f8db upstream.
In module_add_modinfo_attrs if sysfs_create_file
fails, we forget to free allocated modinfo_attrs
and roll back the sysfs files.
Fixes: 03e88ae1b13d ("[PATCH] fix module sysfs files reference counting")
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit eddf3e9c7c7e4d0707c68d1bb22cc6ec8aef7d4a upstream.
The following crash was observed:
Unable to handle kernel NULL pointer dereference at 0000000000000158
Internal error: Oops: 96000004 [#1] SMP
pc : resend_irqs+0x68/0xb0
lr : resend_irqs+0x64/0xb0
...
Call trace:
resend_irqs+0x68/0xb0
tasklet_action_common.isra.6+0x84/0x138
tasklet_action+0x2c/0x38
__do_softirq+0x120/0x324
run_ksoftirqd+0x44/0x60
smpboot_thread_fn+0x1ac/0x1e8
kthread+0x134/0x138
ret_from_fork+0x10/0x18
The reason for this is that the interrupt resend mechanism happens in soft
interrupt context, which is a asynchronous mechanism versus other
operations on interrupts. free_irq() does not take resend handling into
account. Thus, the irq descriptor might be already freed before the resend
tasklet is executed. resend_irqs() does not check the return value of the
interrupt descriptor lookup and derefences the return value
unconditionally.
1):
__setup_irq
irq_startup
check_irq_resend // activate softirq to handle resend irq
2):
irq_domain_free_irqs
irq_free_descs
free_desc
call_rcu(&desc->rcu, delayed_free_desc)
3):
__do_softirq
tasklet_action
resend_irqs
desc = irq_to_desc(irq)
desc->handle_irq(desc) // desc is NULL --> Ooops
Fix this by adding a NULL pointer check in resend_irqs() before derefencing
the irq descriptor.
Fixes: a4633adcdbc1 ("[PATCH] genirq: add genirq sw IRQ-retrigger")
Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/1630ae13-5c8e-901e-de09-e740b6a426a7@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 97a61369830ab085df5aed0ff9256f35b07d425a upstream.
If a new child cgroup is created in the frozen cgroup hierarchy
(one or more of ancestor cgroups is frozen), the CGRP_FREEZE cgroup
flag should be set. Otherwise if a process will be attached to the
child cgroup, it won't become frozen.
The problem can be reproduced with the test_cgfreezer_mkdir test.
This is the output before this patch:
~/test_freezer
ok 1 test_cgfreezer_simple
ok 2 test_cgfreezer_tree
ok 3 test_cgfreezer_forkbomb
Cgroup /sys/fs/cgroup/cg_test_mkdir_A/cg_test_mkdir_B isn't frozen
not ok 4 test_cgfreezer_mkdir
ok 5 test_cgfreezer_rmdir
ok 6 test_cgfreezer_migrate
ok 7 test_cgfreezer_ptrace
ok 8 test_cgfreezer_stopped
ok 9 test_cgfreezer_ptraced
ok 10 test_cgfreezer_vfork
And with this patch:
~/test_freezer
ok 1 test_cgfreezer_simple
ok 2 test_cgfreezer_tree
ok 3 test_cgfreezer_forkbomb
ok 4 test_cgfreezer_mkdir
ok 5 test_cgfreezer_rmdir
ok 6 test_cgfreezer_migrate
ok 7 test_cgfreezer_ptrace
ok 8 test_cgfreezer_stopped
ok 9 test_cgfreezer_ptraced
ok 10 test_cgfreezer_vfork
Reported-by: Mark Crossen <mcrossen@fb.com>
Signed-off-by: Roman Gushchin <guro@fb.com>
Fixes: 76f969e8948d ("cgroup: cgroup v2 freezer")
Cc: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org # v5.2+
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 5e2d2cc2588bd3307ce3937acbc2ed03c830a861 upstream.
do_sched_cfs_period_timer() will refill cfs_b runtime and call
distribute_cfs_runtime to unthrottle cfs_rq, sometimes cfs_b->runtime
will allocate all quota to one cfs_rq incorrectly, then other cfs_rqs
attached to this cfs_b can't get runtime and will be throttled.
We find that one throttled cfs_rq has non-negative
cfs_rq->runtime_remaining and cause an unexpetced cast from s64 to u64
in snippet:
distribute_cfs_runtime() {
runtime = -cfs_rq->runtime_remaining + 1;
}
The runtime here will change to a large number and consume all
cfs_b->runtime in this cfs_b period.
According to Ben Segall, the throttled cfs_rq can have
account_cfs_rq_runtime called on it because it is throttled before
idle_balance, and the idle_balance calls update_rq_clock to add time
that is accounted to the task.
This commit prevents cfs_rq to be assgined new runtime if it has been
throttled until that distribute_cfs_runtime is called.
Signed-off-by: Liangyan <liangyan.peng@linux.alibaba.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Reviewed-by: Ben Segall <bsegall@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: shanpeic@linux.alibaba.com
Cc: stable@vger.kernel.org
Cc: xlpang@linux.alibaba.com
Fixes: d3d9dc330236 ("sched: Throttle entities exceeding their allowed bandwidth")
Link: https://lkml.kernel.org/r/20190826121633.6538-1-liangyan.peng@linux.alibaba.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit f1c6ece23729257fb46562ff9224cf5f61b818da ]
lockdep reports the following deadlock scenario:
WARNING: possible circular locking dependency detected
kworker/1:1/48 is trying to acquire lock:
000000008d7a62b2 (text_mutex){+.+.}, at: kprobe_optimizer+0x163/0x290
but task is already holding lock:
00000000850b5e2d (module_mutex){+.+.}, at: kprobe_optimizer+0x31/0x290
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (module_mutex){+.+.}:
__mutex_lock+0xac/0x9f0
mutex_lock_nested+0x1b/0x20
set_all_modules_text_rw+0x22/0x90
ftrace_arch_code_modify_prepare+0x1c/0x20
ftrace_run_update_code+0xe/0x30
ftrace_startup_enable+0x2e/0x50
ftrace_startup+0xa7/0x100
register_ftrace_function+0x27/0x70
arm_kprobe+0xb3/0x130
enable_kprobe+0x83/0xa0
enable_trace_kprobe.part.0+0x2e/0x80
kprobe_register+0x6f/0xc0
perf_trace_event_init+0x16b/0x270
perf_kprobe_init+0xa7/0xe0
perf_kprobe_event_init+0x3e/0x70
perf_try_init_event+0x4a/0x140
perf_event_alloc+0x93a/0xde0
__do_sys_perf_event_open+0x19f/0xf30
__x64_sys_perf_event_open+0x20/0x30
do_syscall_64+0x65/0x1d0
entry_SYSCALL_64_after_hwframe+0x49/0xbe
-> #0 (text_mutex){+.+.}:
__lock_acquire+0xfcb/0x1b60
lock_acquire+0xca/0x1d0
__mutex_lock+0xac/0x9f0
mutex_lock_nested+0x1b/0x20
kprobe_optimizer+0x163/0x290
process_one_work+0x22b/0x560
worker_thread+0x50/0x3c0
kthread+0x112/0x150
ret_from_fork+0x3a/0x50
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(module_mutex);
lock(text_mutex);
lock(module_mutex);
lock(text_mutex);
*** DEADLOCK ***
As a reproducer I've been using bcc's funccount.py
(https://github.com/iovisor/bcc/blob/master/tools/funccount.py),
for example:
# ./funccount.py '*interrupt*'
That immediately triggers the lockdep splat.
Fix by acquiring text_mutex before module_mutex in kprobe_optimizer().
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: d5b844a2cf50 ("ftrace/x86: Remove possible deadlock between register_kprobe() and ftrace_run_update_code()")
Link: http://lkml.kernel.org/r/20190812184302.GA7010@xps-13
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit b0fdc01354f45d43f082025636ef808968a27b36 ]
If a task is PI-blocked (blocking on sleeping spinlock) then we don't want to
schedule a new kworker if we schedule out due to lock contention because !RT
does not do that as well. A spinning spinlock disables preemption and a worker
does not schedule out on lock contention (but spin).
On RT the RW-semaphore implementation uses an rtmutex so
tsk_is_pi_blocked() will return true if a task blocks on it. In this case we
will now start a new worker which may deadlock if one worker is waiting on
progress from another worker. Since a RW-semaphore starts a new worker on !RT,
we should do the same on RT.
XFS is able to trigger this deadlock.
Allow to schedule new worker if the current worker is PI-blocked.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20190816160626.12742-1-bigeasy@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit c751798aa224fadc5124b49eeb38fb468c0fa039 upstream.
syzkaller managed to trigger the warning in bpf_jit_free() which checks via
bpf_prog_kallsyms_verify_off() for potentially unlinked JITed BPF progs
in kallsyms, and subsequently trips over GPF when walking kallsyms entries:
[...]
8021q: adding VLAN 0 to HW filter on device batadv0
8021q: adding VLAN 0 to HW filter on device batadv0
WARNING: CPU: 0 PID: 9869 at kernel/bpf/core.c:810 bpf_jit_free+0x1e8/0x2a0
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 9869 Comm: kworker/0:7 Not tainted 5.0.0-rc8+ #1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events bpf_prog_free_deferred
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x113/0x167 lib/dump_stack.c:113
panic+0x212/0x40b kernel/panic.c:214
__warn.cold.8+0x1b/0x38 kernel/panic.c:571
report_bug+0x1a4/0x200 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:178 [inline]
do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271
do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:290
invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973
RIP: 0010:bpf_jit_free+0x1e8/0x2a0
Code: 02 4c 89 e2 83 e2 07 38 d0 7f 08 84 c0 0f 85 86 00 00 00 48 ba 00 02 00 00 00 00 ad de 0f b6 43 02 49 39 d6 0f 84 5f fe ff ff <0f> 0b e9 58 fe ff ff 48 b8 00 00 00 00 00 fc ff df 4c 89 e2 48 c1
RSP: 0018:ffff888092f67cd8 EFLAGS: 00010202
RAX: 0000000000000007 RBX: ffffc90001947000 RCX: ffffffff816e9d88
RDX: dead000000000200 RSI: 0000000000000008 RDI: ffff88808769f7f0
RBP: ffff888092f67d00 R08: fffffbfff1394059 R09: fffffbfff1394058
R10: fffffbfff1394058 R11: ffffffff89ca02c7 R12: ffffc90001947002
R13: ffffc90001947020 R14: ffffffff881eca80 R15: ffff88808769f7e8
BUG: unable to handle kernel paging request at fffffbfff400d000
#PF error: [normal kernel read fault]
PGD 21ffee067 P4D 21ffee067 PUD 21ffed067 PMD 9f942067 PTE 0
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 9869 Comm: kworker/0:7 Not tainted 5.0.0-rc8+ #1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events bpf_prog_free_deferred
RIP: 0010:bpf_get_prog_addr_region kernel/bpf/core.c:495 [inline]
RIP: 0010:bpf_tree_comp kernel/bpf/core.c:558 [inline]
RIP: 0010:__lt_find include/linux/rbtree_latch.h:115 [inline]
RIP: 0010:latch_tree_find include/linux/rbtree_latch.h:208 [inline]
RIP: 0010:bpf_prog_kallsyms_find+0x107/0x2e0 kernel/bpf/core.c:632
Code: 00 f0 ff ff 44 38 c8 7f 08 84 c0 0f 85 fa 00 00 00 41 f6 45 02 01 75 02 0f 0b 48 39 da 0f 82 92 00 00 00 48 89 d8 48 c1 e8 03 <42> 0f b6 04 30 84 c0 74 08 3c 03 0f 8e 45 01 00 00 8b 03 48 c1 e0
[...]
Upon further debugging, it turns out that whenever we trigger this
issue, the kallsyms removal in bpf_prog_ksym_node_del() was /skipped/
but yet bpf_jit_free() reported that the entry is /in use/.
Problem is that symbol exposure via bpf_prog_kallsyms_add() but also
perf_event_bpf_event() were done /after/ bpf_prog_new_fd(). Once the
fd is exposed to the public, a parallel close request came in right
before we attempted to do the bpf_prog_kallsyms_add().
Given at this time the prog reference count is one, we start to rip
everything underneath us via bpf_prog_release() -> bpf_prog_put().
The memory is eventually released via deferred free, so we're seeing
that bpf_jit_free() has a kallsym entry because we added it from
bpf_prog_load() but /after/ bpf_prog_put() from the remote CPU.
Therefore, move both notifications /before/ we install the fd. The
issue was never seen between bpf_prog_alloc_id() and bpf_prog_new_fd()
because upon bpf_prog_get_fd_by_id() we'll take another reference to
the BPF prog, so we're still holding the original reference from the
bpf_prog_load().
Fixes: 6ee52e2a3fe4 ("perf, bpf: Introduce PERF_RECORD_BPF_EVENT")
Fixes: 74451e66d516 ("bpf: make jited programs visible in traces")
Reported-by: syzbot+bd3bba6ff3fcea7a6ec6@syzkaller.appspotmail.com
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Song Liu <songliubraving@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 372e0d01da71c84dcecf7028598a33813b0d5256 upstream.
The race between adding a function probe and reading the probes that exist
is very subtle. It needs a comment. Also, the issue can also happen if the
probe has has the EMPTY_HASH as its func_hash.
Cc: stable@vger.kernel.org
Fixes: 7b60f3d876156 ("ftrace: Dynamically create the probe ftrace_ops for the trace_array")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 5b0022dd32b7c2e15edf1827ba80aa1407edf9ff upstream.
In register_ftrace_function_probe(), we are not checking the return
value of alloc_and_copy_ftrace_hash(). The subsequent call to
ftrace_match_records() may end up dereferencing the same. Add a check to
ensure this doesn't happen.
Link: http://lkml.kernel.org/r/26e92574f25ad23e7cafa3cf5f7a819de1832cbe.1562249521.git.naveen.n.rao@linux.vnet.ibm.com
Cc: stable@vger.kernel.org
Fixes: 1ec3a81a0cf42 ("ftrace: Have each function probe use its own ftrace_ops")
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 7bd46644ea0f6021dc396a39a8bfd3a58f6f1f9f upstream.
LTP testsuite on powerpc results in the below crash:
Unable to handle kernel paging request for data at address 0x00000000
Faulting instruction address: 0xc00000000029d800
Oops: Kernel access of bad area, sig: 11 [#1]
LE SMP NR_CPUS=2048 NUMA PowerNV
...
CPU: 68 PID: 96584 Comm: cat Kdump: loaded Tainted: G W
NIP: c00000000029d800 LR: c00000000029dac4 CTR: c0000000001e6ad0
REGS: c0002017fae8ba10 TRAP: 0300 Tainted: G W
MSR: 9000000000009033 <SF,HV,EE,ME,IR,DR,RI,LE> CR: 28022422 XER: 20040000
CFAR: c00000000029d90c DAR: 0000000000000000 DSISR: 40000000 IRQMASK: 0
...
NIP [c00000000029d800] t_probe_next+0x60/0x180
LR [c00000000029dac4] t_mod_start+0x1a4/0x1f0
Call Trace:
[c0002017fae8bc90] [c000000000cdbc40] _cond_resched+0x10/0xb0 (unreliable)
[c0002017fae8bce0] [c0000000002a15b0] t_start+0xf0/0x1c0
[c0002017fae8bd30] [c0000000004ec2b4] seq_read+0x184/0x640
[c0002017fae8bdd0] [c0000000004a57bc] sys_read+0x10c/0x300
[c0002017fae8be30] [c00000000000b388] system_call+0x5c/0x70
The test (ftrace_set_ftrace_filter.sh) is part of ftrace stress tests
and the crash happens when the test does 'cat
$TRACING_PATH/set_ftrace_filter'.
The address points to the second line below, in t_probe_next(), where
filter_hash is dereferenced:
hash = iter->probe->ops.func_hash->filter_hash;
size = 1 << hash->size_bits;
This happens due to a race with register_ftrace_function_probe(). A new
ftrace_func_probe is created and added into the func_probes list in
trace_array under ftrace_lock. However, before initializing the filter,
we drop ftrace_lock, and re-acquire it after acquiring regex_lock. If
another process is trying to read set_ftrace_filter, it will be able to
acquire ftrace_lock during this window and it will end up seeing a NULL
filter_hash.
Fix this by just checking for a NULL filter_hash in t_probe_next(). If
the filter_hash is NULL, then this probe is just being added and we can
simply return from here.
Link: http://lkml.kernel.org/r/05e021f757625cbbb006fad41380323dbe4e3b43.1562249521.git.naveen.n.rao@linux.vnet.ibm.com
Cc: stable@vger.kernel.org
Fixes: 7b60f3d876156 ("ftrace: Dynamically create the probe ftrace_ops for the trace_array")
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 99143f82a255e7f054bead8443462fae76dd829e ]
While reviewing another read_slowpath patch, both Will and I noticed
another missing ACQUIRE, namely:
X = 0;
CPU0 CPU1
rwsem_down_read()
for (;;) {
set_current_state(TASK_UNINTERRUPTIBLE);
X = 1;
rwsem_up_write();
rwsem_mark_wake()
atomic_long_add(adjustment, &sem->count);
smp_store_release(&waiter->task, NULL);
if (!waiter.task)
break;
...
}
r = X;
Allows 'r == 0'.
Reported-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reported-by: Will Deacon <will@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit e1b98fa316648420d0434d9ff5b92ad6609ba6c3 ]
LTP mtest06 has been observed to occasionally hit "still mapped when
deleted" and following BUG_ON on arm64.
The extra mapcount originated from pagefault handler, which handled
pagefault for vma that has already been detached. vma is detached
under mmap_sem write lock by detach_vmas_to_be_unmapped(), which
also invalidates vmacache.
When the pagefault handler (under mmap_sem read lock) calls
find_vma(), vmacache_valid() wrongly reports vmacache as valid.
After rwsem down_read() returns via 'queue empty' path (as of v5.2),
it does so without an ACQUIRE on sem->count:
down_read()
__down_read()
rwsem_down_read_failed()
__rwsem_down_read_failed_common()
raw_spin_lock_irq(&sem->wait_lock);
if (list_empty(&sem->wait_list)) {
if (atomic_long_read(&sem->count) >= 0) {
raw_spin_unlock_irq(&sem->wait_lock);
return sem;
The problem can be reproduced by running LTP mtest06 in a loop and
building the kernel (-j $NCPUS) in parallel. It does reproduces since
v4.20 on arm64 HPE Apollo 70 (224 CPUs, 256GB RAM, 2 nodes). It
triggers reliably in about an hour.
The patched kernel ran fine for 10+ hours.
Signed-off-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Will Deacon <will@kernel.org>
Acked-by: Waiman Long <longman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dbueso@suse.de
Fixes: 4b486b535c33 ("locking/rwsem: Exit read lock slowpath if queue empty & no writer")
Link: https://lkml.kernel.org/r/50b8914e20d1d62bb2dee42d342836c2c16ebee7.1563438048.git.jstancek@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit d8ad55538abe443919e20e0bb996561bca9cad84 ]
The dma required_mask needs to reflect the actual addressing capabilities
needed to handle the whole system RAM. When truncated down to the bus
addressing capabilities dma_addressing_limited() will incorrectly signal
no limitations for devices which are restricted by the bus_dma_mask.
Fixes: b4ebe6063204 (dma-direct: implement complete bus_dma_mask handling)
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Tested-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit d0ff14fdc987303aeeb7de6f1bd72c3749ae2a9b upstream.
If alloc_descs() fails before irq_sysfs_init() has run, free_desc() in the
cleanup path will call kobject_del() even though the kobject has not been
added with kobject_add().
Fix this by making the call to kobject_del() conditional on whether
irq_sysfs_init() has run.
This problem surfaced because commit aa30f47cf666 ("kobject: Add support
for default attribute groups to kobj_type") makes kobject_del() stricter
about pairing with kobject_add(). If the pairing is incorrrect, a WARNING
and backtrace occur in sysfs_remove_group() because there is no parent.
[ tglx: Add a comment to the code and make it work with CONFIG_SYSFS=n ]
Fixes: ecb3f394c5db ("genirq: Expose interrupt information through sysfs")
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/1564703564-4116-1-git-send-email-mikelley@microsoft.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 7b2b55da1db10a5525460633ae4b6fb0be060c41 upstream.
Only when calling the poll syscall the first time can user receive
POLLPRI correctly. After that, user always fails to acquire the event
signal.
Reproduce case:
1. Get the monitor code in Documentation/accounting/psi.txt
2. Run it, and wait for the event triggered.
3. Kill and restart the process.
The question is why we can end up with poll_scheduled = 1 but the work
not running (which would reset it to 0). And the answer is because the
scheduling side sees group->poll_kworker under RCU protection and then
schedules it, but here we cancel the work and destroy the worker. The
cancel needs to pair with resetting the poll_scheduled flag.
Link: http://lkml.kernel.org/r/1566357985-97781-1-git-send-email-joseph.qi@linux.alibaba.com
Signed-off-by: Jason Xing <kerneljasonxing@linux.alibaba.com>
Signed-off-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Caspar Zhang <caspar@linux.alibaba.com>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 04e048cf09d7b5fc995817cdc5ae1acd4482429c ]
When a process creates a new trigger by writing into /proc/pressure/*
files, permissions to write such a file should be used to determine whether
the process is allowed to do so or not. Current implementation would also
require such a process to have setsched capability. Setting of psi trigger
thread's scheduling policy is an implementation detail and should not be
exposed to the user level. Remove the permission check by using _nocheck
version of the function.
Suggested-by: Nick Kralevich <nnk@google.com>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: lizefan@huawei.com
Cc: mingo@redhat.com
Cc: akpm@linux-foundation.org
Cc: kernel-team@android.com
Cc: dennisszhou@gmail.com
Cc: dennis@kernel.org
Cc: hannes@cmpxchg.org
Cc: axboe@kernel.dk
Link: https://lkml.kernel.org/r/20190730013310.162367-1-surenb@google.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
Steven Rostedt (VMware)
Srivatsa S. Bhat (VMware)
Michal Hocko
Will Deacon
Balasubramani Vivekanandan
Allan Zhang
Valdis Kletnieks
KeMeng Shi
Mathieu Desnoyers
Wanpeng Li
Li RongQing
Tom Zanussi
Tetsuo Handa
Miroslav Benes
Thadeu Lima de Souza Cascardo
Peter Zijlstra
Vincent Whitchurch
Miles Chen
Masami Hiramatsu
Douglas RAILLARD
Thomas Gleixner
Phil Auld
Juri Lelli
Vincent Guittot
Paul E. McKenney
Marc Zyngier
Jessica Yu
Yang Yingliang
YueHaibing
Yunfeng Ye
Roman Gushchin
Liangyan
Andrea Righi
Sebastian Andrzej Siewior
Daniel Borkmann
Naveen N. Rao
Jan Stancek
Lucas Stach
Michael Kelley
Jason Xing
Suren Baghdasaryan