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2020-02-19sched/uclamp: Reject negative values in cpu_uclamp_write()Qais Yousef
commit b562d140649966d4daedd0483a8fe59ad3bb465a upstream. The check to ensure that the new written value into cpu.uclamp.{min,max} is within range, [0:100], wasn't working because of the signed comparison 7301 if (req.percent > UCLAMP_PERCENT_SCALE) { 7302 req.ret = -ERANGE; 7303 return req; 7304 } # echo -1 > cpu.uclamp.min # cat cpu.uclamp.min 42949671.96 Cast req.percent into u64 to force the comparison to be unsigned and work as intended in capacity_from_percent(). # echo -1 > cpu.uclamp.min sh: write error: Numerical result out of range Fixes: 2480c093130f ("sched/uclamp: Extend CPU's cgroup controller") Signed-off-by: Qais Yousef <qais.yousef@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20200114210947.14083-1-qais.yousef@arm.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-19ACPI: PM: s2idle: Avoid possible race related to the EC GPERafael J. Wysocki
commit e3728b50cd9be7d4b1469447cdf1feb93e3b7adb upstream. It is theoretically possible for the ACPI EC GPE to be set after the s2idle_ops->wake() called from s2idle_loop() has returned and before the subsequent pm_wakeup_pending() check is carried out. If that happens, the resulting wakeup event will cause the system to resume even though it may be a spurious one. To avoid that race, first make the ->wake() callback in struct platform_s2idle_ops return a bool value indicating whether or not to let the system resume and rearrange s2idle_loop() to use that value instad of the direct pm_wakeup_pending() call if ->wake() is present. Next, rework acpi_s2idle_wake() to process EC events and check pm_wakeup_pending() before re-arming the SCI for system wakeup to prevent it from triggering prematurely and add comments to that function to explain the rationale for the new code flow. Fixes: 56b991849009 ("PM: sleep: Simplify suspend-to-idle control flow") Cc: 5.4+ <stable@vger.kernel.org> # 5.4+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-14sched/uclamp: Fix a bug in propagating uclamp value in new cgroupsQais Yousef
commit 7226017ad37a888915628e59a84a2d1e57b40707 upstream. When a new cgroup is created, the effective uclamp value wasn't updated with a call to cpu_util_update_eff() that looks at the hierarchy and update to the most restrictive values. Fix it by ensuring to call cpu_util_update_eff() when a new cgroup becomes online. Without this change, the newly created cgroup uses the default root_task_group uclamp values, which is 1024 for both uclamp_{min, max}, which will cause the rq to to be clamped to max, hence cause the system to run at max frequency. The problem was observed on Ubuntu server and was reproduced on Debian and Buildroot rootfs. By default, Ubuntu and Debian create a cpu controller cgroup hierarchy and add all tasks to it - which creates enough noise to keep the rq uclamp value at max most of the time. Imitating this behavior makes the problem visible in Buildroot too which otherwise looks fine since it's a minimal userspace. Fixes: 0b60ba2dd342 ("sched/uclamp: Propagate parent clamps") Reported-by: Doug Smythies <dsmythies@telus.net> Signed-off-by: Qais Yousef <qais.yousef@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Doug Smythies <dsmythies@telus.net> Link: https://lore.kernel.org/lkml/000701d5b965$361b6c60$a2524520$@net/ Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-11perf/core: Fix mlock accounting in perf_mmap()Song Liu
commit 003461559ef7a9bd0239bae35a22ad8924d6e9ad upstream. Decreasing sysctl_perf_event_mlock between two consecutive perf_mmap()s of a perf ring buffer may lead to an integer underflow in locked memory accounting. This may lead to the undesired behaviors, such as failures in BPF map creation. Address this by adjusting the accounting logic to take into account the possibility that the amount of already locked memory may exceed the current limit. Fixes: c4b75479741c ("perf/core: Make the mlock accounting simple again") Suggested-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: <stable@vger.kernel.org> Acked-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Link: https://lkml.kernel.org/r/20200123181146.2238074-1-songliubraving@fb.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-11clocksource: Prevent double add_timer_on() for watchdog_timerKonstantin Khlebnikov
commit febac332a819f0e764aa4da62757ba21d18c182b upstream. Kernel crashes inside QEMU/KVM are observed: kernel BUG at kernel/time/timer.c:1154! BUG_ON(timer_pending(timer) || !timer->function) in add_timer_on(). At the same time another cpu got: general protection fault: 0000 [#1] SMP PTI of poinson pointer 0xdead000000000200 in: __hlist_del at include/linux/list.h:681 (inlined by) detach_timer at kernel/time/timer.c:818 (inlined by) expire_timers at kernel/time/timer.c:1355 (inlined by) __run_timers at kernel/time/timer.c:1686 (inlined by) run_timer_softirq at kernel/time/timer.c:1699 Unfortunately kernel logs are badly scrambled, stacktraces are lost. Printing the timer->function before the BUG_ON() pointed to clocksource_watchdog(). The execution of clocksource_watchdog() can race with a sequence of clocksource_stop_watchdog() .. clocksource_start_watchdog(): expire_timers() detach_timer(timer, true); timer->entry.pprev = NULL; raw_spin_unlock_irq(&base->lock); call_timer_fn clocksource_watchdog() clocksource_watchdog_kthread() or clocksource_unbind() spin_lock_irqsave(&watchdog_lock, flags); clocksource_stop_watchdog(); del_timer(&watchdog_timer); watchdog_running = 0; spin_unlock_irqrestore(&watchdog_lock, flags); spin_lock_irqsave(&watchdog_lock, flags); clocksource_start_watchdog(); add_timer_on(&watchdog_timer, ...); watchdog_running = 1; spin_unlock_irqrestore(&watchdog_lock, flags); spin_lock(&watchdog_lock); add_timer_on(&watchdog_timer, ...); BUG_ON(timer_pending(timer) || !timer->function); timer_pending() -> true BUG() I.e. inside clocksource_watchdog() watchdog_timer could be already armed. Check timer_pending() before calling add_timer_on(). This is sufficient as all operations are synchronized by watchdog_lock. Fixes: 75c5158f70c0 ("timekeeping: Update clocksource with stop_machine") Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/158048693917.4378.13823603769948933793.stgit@buzz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-11x86/apic/msi: Plug non-maskable MSI affinity raceThomas Gleixner
commit 6f1a4891a5928a5969c87fa5a584844c983ec823 upstream. Evan tracked down a subtle race between the update of the MSI message and the device raising an interrupt internally on PCI devices which do not support MSI masking. The update of the MSI message is non-atomic and consists of either 2 or 3 sequential 32bit wide writes to the PCI config space. - Write address low 32bits - Write address high 32bits (If supported by device) - Write data When an interrupt is migrated then both address and data might change, so the kernel attempts to mask the MSI interrupt first. But for MSI masking is optional, so there exist devices which do not provide it. That means that if the device raises an interrupt internally between the writes then a MSI message is sent built from half updated state. On x86 this can lead to spurious interrupts on the wrong interrupt vector when the affinity setting changes both address and data. As a consequence the device interrupt can be lost causing the device to become stuck or malfunctioning. Evan tried to handle that by disabling MSI accross an MSI message update. That's not feasible because disabling MSI has issues on its own: If MSI is disabled the PCI device is routing an interrupt to the legacy INTx mechanism. The INTx delivery can be disabled, but the disablement is not working on all devices. Some devices lose interrupts when both MSI and INTx delivery are disabled. Another way to solve this would be to enforce the allocation of the same vector on all CPUs in the system for this kind of screwed devices. That could be done, but it would bring back the vector space exhaustion problems which got solved a few years ago. Fortunately the high address (if supported by the device) is only relevant when X2APIC is enabled which implies interrupt remapping. In the interrupt remapping case the affinity setting is happening at the interrupt remapping unit and the PCI MSI message is programmed only once when the PCI device is initialized. That makes it possible to solve it with a two step update: 1) Target the MSI msg to the new vector on the current target CPU 2) Target the MSI msg to the new vector on the new target CPU In both cases writing the MSI message is only changing a single 32bit word which prevents the issue of inconsistency. After writing the final destination it is necessary to check whether the device issued an interrupt while the intermediate state #1 (new vector, current CPU) was in effect. This is possible because the affinity change is always happening on the current target CPU. The code runs with interrupts disabled, so the interrupt can be detected by checking the IRR of the local APIC. If the vector is pending in the IRR then the interrupt is retriggered on the new target CPU by sending an IPI for the associated vector on the target CPU. This can cause spurious interrupts on both the local and the new target CPU. 1) If the new vector is not in use on the local CPU and the device affected by the affinity change raised an interrupt during the transitional state (step #1 above) then interrupt entry code will ignore that spurious interrupt. The vector is marked so that the 'No irq handler for vector' warning is supressed once. 2) If the new vector is in use already on the local CPU then the IRR check might see an pending interrupt from the device which is using this vector. The IPI to the new target CPU will then invoke the handler of the device, which got the affinity change, even if that device did not issue an interrupt 3) If the new vector is in use already on the local CPU and the device affected by the affinity change raised an interrupt during the transitional state (step #1 above) then the handler of the device which uses that vector on the local CPU will be invoked. expose issues in device driver interrupt handlers which are not prepared to handle a spurious interrupt correctly. This not a regression, it's just exposing something which was already broken as spurious interrupts can happen for a lot of reasons and all driver handlers need to be able to deal with them. Reported-by: Evan Green <evgreen@chromium.org> Debugged-by: Evan Green <evgreen@chromium.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Evan Green <evgreen@chromium.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/87imkr4s7n.fsf@nanos.tec.linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-11bpf, devmap: Pass lockdep expression to RCU listsAmol Grover
commit 485ec2ea9cf556e9c120e07961b7b459d776a115 upstream. head is traversed using hlist_for_each_entry_rcu outside an RCU read-side critical section but under the protection of dtab->index_lock. Hence, add corresponding lockdep expression to silence false-positive lockdep warnings, and harden RCU lists. Fixes: 6f9d451ab1a3 ("xdp: Add devmap_hash map type for looking up devices by hashed index") Signed-off-by: Amol Grover <frextrite@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Acked-by: Toke Høiland-Jørgensen <toke@redhat.com> Link: https://lore.kernel.org/bpf/20200123120437.26506-1-frextrite@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-11crypto: pcrypt - Avoid deadlock by using per-instance padata queuesHerbert Xu
commit bbefa1dd6a6d53537c11624752219e39959d04fb upstream. If the pcrypt template is used multiple times in an algorithm, then a deadlock occurs because all pcrypt instances share the same padata_instance, which completes requests in the order submitted. That is, the inner pcrypt request waits for the outer pcrypt request while the outer request is already waiting for the inner. This patch fixes this by allocating a set of queues for each pcrypt instance instead of using two global queues. In order to maintain the existing user-space interface, the pinst structure remains global so any sysfs modifications will apply to every pcrypt instance. Note that when an update occurs we have to allocate memory for every pcrypt instance. Should one of the allocations fail we will abort the update without rolling back changes already made. The new per-instance data structure is called padata_shell and is essentially a wrapper around parallel_data. Reproducer: #include <linux/if_alg.h> #include <sys/socket.h> #include <unistd.h> int main() { struct sockaddr_alg addr = { .salg_type = "aead", .salg_name = "pcrypt(pcrypt(rfc4106-gcm-aesni))" }; int algfd, reqfd; char buf[32] = { 0 }; algfd = socket(AF_ALG, SOCK_SEQPACKET, 0); bind(algfd, (void *)&addr, sizeof(addr)); setsockopt(algfd, SOL_ALG, ALG_SET_KEY, buf, 20); reqfd = accept(algfd, 0, 0); write(reqfd, buf, 32); read(reqfd, buf, 16); } Reported-by: syzbot+56c7151cad94eec37c521f0e47d2eee53f9361c4@syzkaller.appspotmail.com Fixes: 5068c7a883d1 ("crypto: pcrypt - Add pcrypt crypto parallelization wrapper") Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Tested-by: Eric Biggers <ebiggers@kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-11ftrace: Protect ftrace_graph_hash with ftrace_syncSteven Rostedt (VMware)
[ Upstream commit 54a16ff6f2e50775145b210bcd94d62c3c2af117 ] As function_graph tracer can run when RCU is not "watching", it can not be protected by synchronize_rcu() it requires running a task on each CPU before it can be freed. Calling schedule_on_each_cpu(ftrace_sync) needs to be used. Link: https://lore.kernel.org/r/20200205131110.GT2935@paulmck-ThinkPad-P72 Cc: stable@vger.kernel.org Fixes: b9b0c831bed26 ("ftrace: Convert graph filter to use hash tables") Reported-by: "Paul E. McKenney" <paulmck@kernel.org> Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-02-11ftrace: Add comment to why rcu_dereference_sched() is open codedSteven Rostedt (VMware)
[ Upstream commit 16052dd5bdfa16dbe18d8c1d4cde2ddab9d23177 ] Because the function graph tracer can execute in sections where RCU is not "watching", the rcu_dereference_sched() for the has needs to be open coded. This is fine because the RCU "flavor" of the ftrace hash is protected by its own RCU handling (it does its own little synchronization on every CPU and does not rely on RCU sched). Acked-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-02-11tracing: Annotate ftrace_graph_notrace_hash pointer with __rcuAmol Grover
[ Upstream commit fd0e6852c407dd9aefc594f54ddcc21d84803d3b ] Fix following instances of sparse error kernel/trace/ftrace.c:5667:29: error: incompatible types in comparison kernel/trace/ftrace.c:5813:21: error: incompatible types in comparison kernel/trace/ftrace.c:5868:36: error: incompatible types in comparison kernel/trace/ftrace.c:5870:25: error: incompatible types in comparison Use rcu_dereference_protected to dereference the newly annotated pointer. Link: http://lkml.kernel.org/r/20200205055701.30195-1-frextrite@gmail.com Signed-off-by: Amol Grover <frextrite@gmail.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-02-11tracing: Annotate ftrace_graph_hash pointer with __rcuAmol Grover
[ Upstream commit 24a9729f831462b1d9d61dc85ecc91c59037243f ] Fix following instances of sparse error kernel/trace/ftrace.c:5664:29: error: incompatible types in comparison kernel/trace/ftrace.c:5785:21: error: incompatible types in comparison kernel/trace/ftrace.c:5864:36: error: incompatible types in comparison kernel/trace/ftrace.c:5866:25: error: incompatible types in comparison Use rcu_dereference_protected to access the __rcu annotated pointer. Link: http://lkml.kernel.org/r/20200201072703.17330-1-frextrite@gmail.com Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Amol Grover <frextrite@gmail.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-02-11padata: Remove broken queue flushingHerbert Xu
commit 07928d9bfc81640bab36f5190e8725894d93b659 upstream. The function padata_flush_queues is fundamentally broken because it cannot force padata users to complete the request that is underway. IOW padata has to passively wait for the completion of any outstanding work. As it stands flushing is used in two places. Its use in padata_stop is simply unnecessary because nothing depends on the queues to be flushed afterwards. The other use in padata_replace is more substantial as we depend on it to free the old pd structure. This patch instead uses the pd->refcnt to dynamically free the pd structure once all requests are complete. Fixes: 2b73b07ab8a4 ("padata: Flush the padata queues actively") Cc: <stable@vger.kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-11alarmtimer: Unregister wakeup source when module get failsStephen Boyd
commit 6b6d188aae79a630957aefd88ff5c42af6553ee3 upstream. The alarmtimer_rtc_add_device() function creates a wakeup source and then tries to grab a module reference. If that fails the function returns early with an error code, but fails to remove the wakeup source. Cleanup this exit path so there is no dangling wakeup source, which is named 'alarmtime' left allocated which will conflict with another RTC device that may be registered later. Fixes: 51218298a25e ("alarmtimer: Ensure RTC module is not unloaded") Signed-off-by: Stephen Boyd <swboyd@chromium.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Douglas Anderson <dianders@chromium.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20200109155910.907-2-swboyd@chromium.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-11tracing: Fix now invalid var_ref_vals assumption in trace actionTom Zanussi
[ Upstream commit d380dcde9a07ca5de4805dee11f58a98ec0ad6ff ] The patch 'tracing: Fix histogram code when expression has same var as value' added code to return an existing variable reference when creating a new variable reference, which resulted in var_ref_vals slots being reused instead of being duplicated. The implementation of the trace action assumes that the end of the var_ref_vals array starting at action_data.var_ref_idx corresponds to the values that will be assigned to the trace params. The patch mentioned above invalidates that assumption, which means that each param needs to explicitly specify its index into var_ref_vals. This fix changes action_data.var_ref_idx to an array of var ref indexes to account for that. Link: https://lore.kernel.org/r/1580335695.6220.8.camel@kernel.org Fixes: 8bcebc77e85f ("tracing: Fix histogram code when expression has same var as value") Signed-off-by: Tom Zanussi <zanussi@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-02-11irqdomain: Fix a memory leak in irq_domain_push_irq()Kevin Hao
commit 0f394daef89b38d58c91118a2b08b8a1b316703b upstream. Fix a memory leak reported by kmemleak: unreferenced object 0xffff000bc6f50e80 (size 128): comm "kworker/23:2", pid 201, jiffies 4294894947 (age 942.132s) hex dump (first 32 bytes): 00 00 00 00 41 00 00 00 86 c0 03 00 00 00 00 00 ....A........... 00 a0 b2 c6 0b 00 ff ff 40 51 fd 10 00 80 ff ff ........@Q...... backtrace: [<00000000e62d2240>] kmem_cache_alloc_trace+0x1a4/0x320 [<00000000279143c9>] irq_domain_push_irq+0x7c/0x188 [<00000000d9f4c154>] thunderx_gpio_probe+0x3ac/0x438 [<00000000fd09ec22>] pci_device_probe+0xe4/0x198 [<00000000d43eca75>] really_probe+0xdc/0x320 [<00000000d3ebab09>] driver_probe_device+0x5c/0xf0 [<000000005b3ecaa0>] __device_attach_driver+0x88/0xc0 [<000000004e5915f5>] bus_for_each_drv+0x7c/0xc8 [<0000000079d4db41>] __device_attach+0xe4/0x140 [<00000000883bbda9>] device_initial_probe+0x18/0x20 [<000000003be59ef6>] bus_probe_device+0x98/0xa0 [<0000000039b03d3f>] deferred_probe_work_func+0x74/0xa8 [<00000000870934ce>] process_one_work+0x1c8/0x470 [<00000000e3cce570>] worker_thread+0x1f8/0x428 [<000000005d64975e>] kthread+0xfc/0x128 [<00000000f0eaa764>] ret_from_fork+0x10/0x18 Fixes: 495c38d3001f ("irqdomain: Add irq_domain_{push,pop}_irq() functions") Signed-off-by: Kevin Hao <haokexin@gmail.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20200120043547.22271-1-haokexin@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-11rcu: Use READ_ONCE() for ->expmask in rcu_read_unlock_special()Paul E. McKenney
commit c51f83c315c392d9776c33eb16a2fe1349d65c7f upstream. The rcu_node structure's ->expmask field is updated only when holding the ->lock, but is also accessed locklessly. This means that all ->expmask updates must use WRITE_ONCE() and all reads carried out without holding ->lock must use READ_ONCE(). This commit therefore changes the lockless ->expmask read in rcu_read_unlock_special() to use READ_ONCE(). Reported-by: syzbot+99f4ddade3c22ab0cf23@syzkaller.appspotmail.com Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Acked-by: Marco Elver <elver@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-11srcu: Apply *_ONCE() to ->srcu_last_gp_endPaul E. McKenney
commit 844a378de3372c923909681706d62336d702531e upstream. The ->srcu_last_gp_end field is accessed from any CPU at any time by synchronize_srcu(), so non-initialization references need to use READ_ONCE() and WRITE_ONCE(). This commit therefore makes that change. Reported-by: syzbot+08f3e9d26e5541e1ecf2@syzkaller.appspotmail.com Acked-by: Marco Elver <elver@google.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-11rcu: Avoid data-race in rcu_gp_fqs_check_wake()Eric Dumazet
commit 6935c3983b246d5fbfebd3b891c825e65c118f2d upstream. The rcu_gp_fqs_check_wake() function uses rcu_preempt_blocked_readers_cgp() to read ->gp_tasks while other cpus might overwrite this field. We need READ_ONCE()/WRITE_ONCE() pairs to avoid compiler tricks and KCSAN splats like the following : BUG: KCSAN: data-race in rcu_gp_fqs_check_wake / rcu_preempt_deferred_qs_irqrestore write to 0xffffffff85a7f190 of 8 bytes by task 7317 on cpu 0: rcu_preempt_deferred_qs_irqrestore+0x43d/0x580 kernel/rcu/tree_plugin.h:507 rcu_read_unlock_special+0xec/0x370 kernel/rcu/tree_plugin.h:659 __rcu_read_unlock+0xcf/0xe0 kernel/rcu/tree_plugin.h:394 rcu_read_unlock include/linux/rcupdate.h:645 [inline] __ip_queue_xmit+0x3b0/0xa40 net/ipv4/ip_output.c:533 ip_queue_xmit+0x45/0x60 include/net/ip.h:236 __tcp_transmit_skb+0xdeb/0x1cd0 net/ipv4/tcp_output.c:1158 __tcp_send_ack+0x246/0x300 net/ipv4/tcp_output.c:3685 tcp_send_ack+0x34/0x40 net/ipv4/tcp_output.c:3691 tcp_cleanup_rbuf+0x130/0x360 net/ipv4/tcp.c:1575 tcp_recvmsg+0x633/0x1a30 net/ipv4/tcp.c:2179 inet_recvmsg+0xbb/0x250 net/ipv4/af_inet.c:838 sock_recvmsg_nosec net/socket.c:871 [inline] sock_recvmsg net/socket.c:889 [inline] sock_recvmsg+0x92/0xb0 net/socket.c:885 sock_read_iter+0x15f/0x1e0 net/socket.c:967 call_read_iter include/linux/fs.h:1864 [inline] new_sync_read+0x389/0x4f0 fs/read_write.c:414 read to 0xffffffff85a7f190 of 8 bytes by task 10 on cpu 1: rcu_gp_fqs_check_wake kernel/rcu/tree.c:1556 [inline] rcu_gp_fqs_check_wake+0x93/0xd0 kernel/rcu/tree.c:1546 rcu_gp_fqs_loop+0x36c/0x580 kernel/rcu/tree.c:1611 rcu_gp_kthread+0x143/0x220 kernel/rcu/tree.c:1768 kthread+0x1d4/0x200 drivers/block/aoe/aoecmd.c:1253 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 10 Comm: rcu_preempt Not tainted 5.3.0+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> [ paulmck: Added another READ_ONCE() for RCU CPU stall warnings. ] Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-11rcu: Use *_ONCE() to protect lockless ->expmask accessesPaul E. McKenney
commit 15c7c972cd26d89a26788e609c53b5a465324a6c upstream. The rcu_node structure's ->expmask field is accessed locklessly when starting a new expedited grace period and when reporting an expedited RCU CPU stall warning. This commit therefore handles the former by taking a snapshot of ->expmask while the lock is held and the latter by applying READ_ONCE() to lockless reads and WRITE_ONCE() to the corresponding updates. Link: https://lore.kernel.org/lkml/CANpmjNNmSOagbTpffHr4=Yedckx9Rm2NuGqC9UqE+AOz5f1-ZQ@mail.gmail.com Reported-by: syzbot+134336b86f728d6e55a0@syzkaller.appspotmail.com Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Acked-by: Marco Elver <elver@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-11tracing: Fix sched switch start/stop refcount racy updatesMathieu Desnoyers
commit 64ae572bc7d0060429e40e1c8d803ce5eb31a0d6 upstream. Reading the sched_cmdline_ref and sched_tgid_ref initial state within tracing_start_sched_switch without holding the sched_register_mutex is racy against concurrent updates, which can lead to tracepoint probes being registered more than once (and thus trigger warnings within tracepoint.c). [ May be the fix for this bug ] Link: https://lore.kernel.org/r/000000000000ab6f84056c786b93@google.com Link: http://lkml.kernel.org/r/20190817141208.15226-1-mathieu.desnoyers@efficios.com Cc: stable@vger.kernel.org CC: Steven Rostedt (VMware) <rostedt@goodmis.org> CC: Joel Fernandes (Google) <joel@joelfernandes.org> CC: Peter Zijlstra <peterz@infradead.org> CC: Thomas Gleixner <tglx@linutronix.de> CC: Paul E. McKenney <paulmck@linux.ibm.com> Reported-by: syzbot+774fddf07b7ab29a1e55@syzkaller.appspotmail.com Fixes: d914ba37d7145 ("tracing: Add support for recording tgid of tasks") Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-11tracing/kprobes: Have uname use __get_str() in print_fmtSteven Rostedt (VMware)
commit 20279420ae3a8ef4c5d9fedc360a2c37a1dbdf1b upstream. Thomas Richter reported: > Test case 66 'Use vfs_getname probe to get syscall args filenames' > is broken on s390, but works on x86. The test case fails with: > > [root@m35lp76 perf]# perf test -F 66 > 66: Use vfs_getname probe to get syscall args filenames > :Recording open file: > [ perf record: Woken up 1 times to write data ] > [ perf record: Captured and wrote 0.004 MB /tmp/__perf_test.perf.data.TCdYj\ > (20 samples) ] > Looking at perf.data file for vfs_getname records for the file we touched: > FAILED! > [root@m35lp76 perf]# The root cause was the print_fmt of the kprobe event that referenced the "ustring" > Setting up the kprobe event using perf command: > > # ./perf probe "vfs_getname=getname_flags:72 pathname=filename:ustring" > > generates this format file: > [root@m35lp76 perf]# cat /sys/kernel/debug/tracing/events/probe/\ > vfs_getname/format > name: vfs_getname > ID: 1172 > format: > field:unsigned short common_type; offset:0; size:2; signed:0; > field:unsigned char common_flags; offset:2; size:1; signed:0; > field:unsigned char common_preempt_count; offset:3; size:1; signed:0; > field:int common_pid; offset:4; size:4; signed:1; > > field:unsigned long __probe_ip; offset:8; size:8; signed:0; > field:__data_loc char[] pathname; offset:16; size:4; signed:1; > > print fmt: "(%lx) pathname=\"%s\"", REC->__probe_ip, REC->pathname Instead of using "__get_str(pathname)" it referenced it directly. Link: http://lkml.kernel.org/r/20200124100742.4050c15e@gandalf.local.home Cc: stable@vger.kernel.org Fixes: 88903c464321 ("tracing/probe: Add ustring type for user-space string") Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Reported-by: Thomas Richter <tmricht@linux.ibm.com> Tested-by: Thomas Richter <tmricht@linux.ibm.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-05tracing/uprobe: Fix to make trace_uprobe_filter alignment safeMasami Hiramatsu
[ Upstream commit b61387cb732cf283d318b2165c44913525fe545f ] Commit 99c9a923e97a ("tracing/uprobe: Fix double perf_event linking on multiprobe uprobe") moved trace_uprobe_filter on trace_probe_event. However, since it introduced a flexible data structure with char array and type casting, the alignment of trace_uprobe_filter can be broken. This changes the type of the array to trace_uprobe_filter data strucure to fix it. Link: http://lore.kernel.org/r/20200120124022.GA14897@hirez.programming.kicks-ass.net Link: http://lkml.kernel.org/r/157966340499.5107.10978352478952144902.stgit@devnote2 Fixes: 99c9a923e97a ("tracing/uprobe: Fix double perf_event linking on multiprobe uprobe") Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-02-05cgroup: Prevent double killing of css when enabling threaded cgroupMichal Koutný
commit 3bc0bb36fa30e95ca829e9cf480e1ef7f7638333 upstream. The test_cgcore_no_internal_process_constraint_on_threads selftest when running with subsystem controlling noise triggers two warnings: > [ 597.443115] WARNING: CPU: 1 PID: 28167 at kernel/cgroup/cgroup.c:3131 cgroup_apply_control_enable+0xe0/0x3f0 > [ 597.443413] WARNING: CPU: 1 PID: 28167 at kernel/cgroup/cgroup.c:3177 cgroup_apply_control_disable+0xa6/0x160 Both stem from a call to cgroup_type_write. The first warning was also triggered by syzkaller. When we're switching cgroup to threaded mode shortly after a subsystem was disabled on it, we can see the respective subsystem css dying there. The warning in cgroup_apply_control_enable is harmless in this case since we're not adding new subsys anyway. The warning in cgroup_apply_control_disable indicates an attempt to kill css of recently disabled subsystem repeatedly. The commit prevents these situations by making cgroup_type_write wait for all dying csses to go away before re-applying subtree controls. When at it, the locations of WARN_ON_ONCE calls are moved so that warning is triggered only when we are about to misuse the dying css. Reported-by: syzbot+5493b2a54d31d6aea629@syzkaller.appspotmail.com Reported-by: Christian Brauner <christian.brauner@ubuntu.com> Signed-off-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-01Revert "um: Enable CONFIG_CONSTRUCTORS"Johannes Berg
commit 87c9366e17259040a9118e06b6dc8de986e5d3d1 upstream. This reverts commit 786b2384bf1c ("um: Enable CONFIG_CONSTRUCTORS"). There are two issues with this commit, uncovered by Anton in tests on some (Debian) systems: 1) I completely forgot to call any constructors if CONFIG_CONSTRUCTORS isn't set. Don't recall now if it just wasn't needed on my system, or if I never tested this case. 2) With that fixed, it works - with CONFIG_CONSTRUCTORS *unset*. If I set CONFIG_CONSTRUCTORS, it fails again, which isn't totally unexpected since whatever wanted to run is likely to have to run before the kernel init etc. that calls the constructors in this case. Basically, some constructors that gcc emits (libc has?) need to run very early during init; the failure mode otherwise was that the ptrace fork test already failed: ---------------------- $ ./linux mem=512M Core dump limits : soft - 0 hard - NONE Checking that ptrace can change system call numbers...check_ptrace : child exited with exitcode 6, while expecting 0; status 0x67f Aborted ---------------------- Thinking more about this, it's clear that we simply cannot support CONFIG_CONSTRUCTORS in UML. All the cases we need now (gcov, kasan) involve not use of the __attribute__((constructor)), but instead some constructor code/entry generated by gcc. Therefore, we cannot distinguish between kernel constructors and system constructors. Thus, revert this commit. Cc: stable@vger.kernel.org [5.4+] Fixes: 786b2384bf1c ("um: Enable CONFIG_CONSTRUCTORS") Reported-by: Anton Ivanov <anton.ivanov@cambridgegreys.com> Signed-off-by: Johannes Berg <johannes.berg@intel.com> Acked-by: Anton Ivanov <anton.ivanov@cambridgegreys.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Richard Weinberger <richard@nod.at>
2020-01-29tracing: Fix histogram code when expression has same var as valueSteven Rostedt (VMware)
commit 8bcebc77e85f3d7536f96845a0fe94b1dddb6af0 upstream. While working on a tool to convert SQL syntex into the histogram language of the kernel, I discovered the following bug: # echo 'first u64 start_time u64 end_time pid_t pid u64 delta' >> synthetic_events # echo 'hist:keys=pid:start=common_timestamp' > events/sched/sched_waking/trigger # echo 'hist:keys=next_pid:delta=common_timestamp-$start,start2=$start:onmatch(sched.sched_waking).trace(first,$start2,common_timestamp,next_pid,$delta)' > events/sched/sched_switch/trigger Would not display any histograms in the sched_switch histogram side. But if I were to swap the location of "delta=common_timestamp-$start" with "start2=$start" Such that the last line had: # echo 'hist:keys=next_pid:start2=$start,delta=common_timestamp-$start:onmatch(sched.sched_waking).trace(first,$start2,common_timestamp,next_pid,$delta)' > events/sched/sched_switch/trigger The histogram works as expected. What I found out is that the expressions clear out the value once it is resolved. As the variables are resolved in the order listed, when processing: delta=common_timestamp-$start The $start is cleared. When it gets to "start2=$start", it errors out with "unresolved symbol" (which is silent as this happens at the location of the trace), and the histogram is dropped. When processing the histogram for variable references, instead of adding a new reference for a variable used twice, use the same reference. That way, not only is it more efficient, but the order will no longer matter in processing of the variables. From Tom Zanussi: "Just to clarify some more about what the problem was is that without your patch, we would have two separate references to the same variable, and during resolve_var_refs(), they'd both want to be resolved separately, so in this case, since the first reference to start wasn't part of an expression, it wouldn't get the read-once flag set, so would be read normally, and then the second reference would do the read-once read and also be read but using read-once. So everything worked and you didn't see a problem: from: start2=$start,delta=common_timestamp-$start In the second case, when you switched them around, the first reference would be resolved by doing the read-once, and following that the second reference would try to resolve and see that the variable had already been read, so failed as unset, which caused it to short-circuit out and not do the trigger action to generate the synthetic event: to: delta=common_timestamp-$start,start2=$start With your patch, we only have the single resolution which happens correctly the one time it's resolved, so this can't happen." Link: https://lore.kernel.org/r/20200116154216.58ca08eb@gandalf.local.home Cc: stable@vger.kernel.org Fixes: 067fe038e70f6 ("tracing: Add variable reference handling to hist triggers") Reviewed-by: Tom Zanuss <zanussi@kernel.org> Tested-by: Tom Zanussi <zanussi@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-29tracing: Do not set trace clock if tracefs lockdown is in effectMasami Ichikawa
commit bf24daac8f2bd5b8affaec03c2be1d20bcdd6837 upstream. When trace_clock option is not set and unstable clcok detected, tracing_set_default_clock() sets trace_clock(ThinkPad A285 is one of case). In that case, if lockdown is in effect, null pointer dereference error happens in ring_buffer_set_clock(). Link: http://lkml.kernel.org/r/20200116131236.3866925-1-masami256@gmail.com Cc: stable@vger.kernel.org Fixes: 17911ff38aa58 ("tracing: Add locked_down checks to the open calls of files created for tracefs") Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1788488 Signed-off-by: Masami Ichikawa <masami256@gmail.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-29tracing/uprobe: Fix double perf_event linking on multiprobe uprobeMasami Hiramatsu
commit 99c9a923e97a583a38050baa92c9377d73946330 upstream. Fix double perf_event linking to trace_uprobe_filter on multiple uprobe event by moving trace_uprobe_filter under trace_probe_event. In uprobe perf event, trace_uprobe_filter data structure is managing target mm filters (in perf_event) related to each uprobe event. Since commit 60d53e2c3b75 ("tracing/probe: Split trace_event related data from trace_probe") left the trace_uprobe_filter data structure in trace_uprobe, if a trace_probe_event has multiple trace_uprobe (multi-probe event), a perf_event is added to different trace_uprobe_filter on each trace_uprobe. This leads a linked list corruption. To fix this issue, move trace_uprobe_filter to trace_probe_event and link it once on each event instead of each probe. Link: http://lkml.kernel.org/r/157862073931.1800.3800576241181489174.stgit@devnote2 Cc: Jiri Olsa <jolsa@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: "Naveen N . Rao" <naveen.n.rao@linux.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: "David S . Miller" <davem@davemloft.net> Cc: Namhyung Kim <namhyung@kernel.org> Cc: =?utf-8?q?Toke_H=C3=B8iland-J?= =?utf-8?b?w7hyZ2Vuc2Vu?= <thoiland@redhat.com> Cc: Jean-Tsung Hsiao <jhsiao@redhat.com> Cc: Jesper Dangaard Brouer <brouer@redhat.com> Cc: stable@vger.kernel.org Fixes: 60d53e2c3b75 ("tracing/probe: Split trace_event related data from trace_probe") Link: https://lkml.kernel.org/r/20200108171611.GA8472@kernel.org Reported-by: Arnaldo Carvalho de Melo <acme@kernel.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-29tracing: trigger: Replace unneeded RCU-list traversalsMasami Hiramatsu
commit aeed8aa3874dc15b9d82a6fe796fd7cfbb684448 upstream. With CONFIG_PROVE_RCU_LIST, I had many suspicious RCU warnings when I ran ftracetest trigger testcases. ----- # dmesg -c > /dev/null # ./ftracetest test.d/trigger ... # dmesg | grep "RCU-list traversed" | cut -f 2 -d ] | cut -f 2 -d " " kernel/trace/trace_events_hist.c:6070 kernel/trace/trace_events_hist.c:1760 kernel/trace/trace_events_hist.c:5911 kernel/trace/trace_events_trigger.c:504 kernel/trace/trace_events_hist.c:1810 kernel/trace/trace_events_hist.c:3158 kernel/trace/trace_events_hist.c:3105 kernel/trace/trace_events_hist.c:5518 kernel/trace/trace_events_hist.c:5998 kernel/trace/trace_events_hist.c:6019 kernel/trace/trace_events_hist.c:6044 kernel/trace/trace_events_trigger.c:1500 kernel/trace/trace_events_trigger.c:1540 kernel/trace/trace_events_trigger.c:539 kernel/trace/trace_events_trigger.c:584 ----- I investigated those warnings and found that the RCU-list traversals in event trigger and hist didn't need to use RCU version because those were called only under event_mutex. I also checked other RCU-list traversals related to event trigger list, and found that most of them were called from event_hist_trigger_func() or hist_unregister_trigger() or register/unregister functions except for a few cases. Replace these unneeded RCU-list traversals with normal list traversal macro and lockdep_assert_held() to check the event_mutex is held. Link: http://lkml.kernel.org/r/157680910305.11685.15110237954275915782.stgit@devnote2 Cc: stable@vger.kernel.org Fixes: 30350d65ac567 ("tracing: Add variable support to hist triggers") Reviewed-by: Tom Zanussi <zanussi@kernel.org> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-29PM: hibernate: fix crashes with init_on_free=1Alexander Potapenko
commit 18451f9f9e5810b8bd1245c5ae166f257e0e2b9d upstream. Upon resuming from hibernation, free pages may contain stale data from the kernel that initiated the resume. This breaks the invariant inflicted by init_on_free=1 that freed pages must be zeroed. To deal with this problem, make clear_free_pages() also clear the free pages when init_on_free is enabled. Fixes: 6471384af2a6 ("mm: security: introduce init_on_alloc=1 and init_on_free=1 boot options") Reported-by: Johannes Stezenbach <js@sig21.net> Signed-off-by: Alexander Potapenko <glider@google.com> Cc: 5.3+ <stable@vger.kernel.org> # 5.3+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-26xdp: Fix cleanup on map free for devmap_hash map typeToke Høiland-Jørgensen
[ Upstream commit 071cdecec57fb5d5df78e6a12114ad7bccea5b0e ] Tetsuo pointed out that it was not only the device unregister hook that was broken for devmap_hash types, it was also cleanup on map free. So better fix this as well. While we're at it, there's no reason to allocate the netdev_map array for DEVMAP_HASH, so skip that and adjust the cost accordingly. Fixes: 6f9d451ab1a3 ("xdp: Add devmap_hash map type for looking up devices by hashed index") Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20191121133612.430414-1-toke@redhat.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-01-26dma-direct: don't check swiotlb=force in dma_direct_map_resourceChristoph Hellwig
[ Upstream commit 4268ac6ae5870af10a7417b22990d615f72f77e2 ] When mapping resources we can't just use swiotlb ram for bounce buffering. Switch to a direct dma_capable check instead. Fixes: cfced786969c ("dma-mapping: remove the default map_resource implementation") Reported-by: Robin Murphy <robin.murphy@arm.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Marek Szyprowski <m.szyprowski@samsung.com> Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-01-26sched/cpufreq: Move the cfs_rq_util_change() call to cpufreq_update_util()Vincent Guittot
[ Upstream commit bef69dd87828ef5d8ecdab8d857cd3a33cf98675 ] update_cfs_rq_load_avg() calls cfs_rq_util_change() every time PELT decays, which might be inefficient when the cpufreq driver has rate limitation. When a task is attached on a CPU, we have this call path: update_load_avg() update_cfs_rq_load_avg() cfs_rq_util_change -- > trig frequency update attach_entity_load_avg() cfs_rq_util_change -- > trig frequency update The 1st frequency update will not take into account the utilization of the newly attached task and the 2nd one might be discarded because of rate limitation of the cpufreq driver. update_cfs_rq_load_avg() is only called by update_blocked_averages() and update_load_avg() so we can move the call to cfs_rq_util_change/cpufreq_update_util() into these two functions. It's also interesting to note that update_load_avg() already calls cfs_rq_util_change() directly for the !SMP case. This change will also ensure that cpufreq_update_util() is called even when there is no more CFS rq in the leaf_cfs_rq_list to update, but only IRQ, RT or DL PELT signals. [ mingo: Minor updates. ] Reported-by: Doug Smythies <dsmythies@telus.net> Tested-by: Doug Smythies <dsmythies@telus.net> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: juri.lelli@redhat.com Cc: linux-pm@vger.kernel.org Cc: mgorman@suse.de Cc: rostedt@goodmis.org Cc: sargun@sargun.me Cc: srinivas.pandruvada@linux.intel.com Cc: tj@kernel.org Cc: xiexiuqi@huawei.com Cc: xiezhipeng1@huawei.com Fixes: 039ae8bcf7a5 ("sched/fair: Fix O(nr_cgroups) in the load balancing path") Link: https://lkml.kernel.org/r/1574083279-799-1-git-send-email-vincent.guittot@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-01-26workqueue: Add RCU annotation for pwq list walkSebastian Andrzej Siewior
[ Upstream commit 49e9d1a9faf2f71fdfd80a30697ee9a15070626d ] An additional check has been recently added to ensure that a RCU related lock is held while the RCU list is iterated. The `pwqs' are sometimes iterated without a RCU lock but with the &wq->mutex acquired leading to a warning. Teach list_for_each_entry_rcu() that the RCU usage is okay if &wq->mutex is acquired during the list traversal. Fixes: 28875945ba98d ("rcu: Add support for consolidated-RCU reader checking") Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-01-26rcu: Fix uninitialized variable in nocb_gp_wait()Dan Carpenter
[ Upstream commit b8889c9c89a2655a231dfed93cc9bdca0930ea67 ] We never set this to false. This probably doesn't affect most people's runtime because GCC will automatically initialize it to false at certain common optimization levels. But that behavior is related to a bug in GCC and obviously should not be relied on. Fixes: 5d6742b37727 ("rcu/nocb: Use rcu_segcblist for no-CBs CPUs") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-01-26sched/core: Further clarify sched_class::set_next_task()Peter Zijlstra
commit a0e813f26ebcb25c0b5e504498fbd796cca1a4ba upstream. It turns out there really is something special to the first set_next_task() invocation. In specific the 'change' pattern really should not cause balance callbacks. 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: bsegall@google.com Cc: dietmar.eggemann@arm.com Cc: juri.lelli@redhat.com Cc: ktkhai@virtuozzo.com Cc: mgorman@suse.de Cc: qais.yousef@arm.com Cc: qperret@google.com Cc: rostedt@goodmis.org Cc: valentin.schneider@arm.com Cc: vincent.guittot@linaro.org Fixes: f95d4eaee6d0 ("sched/{rt,deadline}: Fix set_next_task vs pick_next_task") Link: https://lkml.kernel.org/r/20191108131909.775434698@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-23tick/sched: Annotate lockless access to last_jiffies_updateEric Dumazet
commit de95a991bb72e009f47e0c4bbc90fc5f594588d5 upstream. syzbot (KCSAN) reported a data-race in tick_do_update_jiffies64(): BUG: KCSAN: data-race in tick_do_update_jiffies64 / tick_do_update_jiffies64 write to 0xffffffff8603d008 of 8 bytes by interrupt on cpu 1: tick_do_update_jiffies64+0x100/0x250 kernel/time/tick-sched.c:73 tick_sched_do_timer+0xd4/0xe0 kernel/time/tick-sched.c:138 tick_sched_timer+0x43/0xe0 kernel/time/tick-sched.c:1292 __run_hrtimer kernel/time/hrtimer.c:1514 [inline] __hrtimer_run_queues+0x274/0x5f0 kernel/time/hrtimer.c:1576 hrtimer_interrupt+0x22a/0x480 kernel/time/hrtimer.c:1638 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline] smp_apic_timer_interrupt+0xdc/0x280 arch/x86/kernel/apic/apic.c:1135 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830 arch_local_irq_restore arch/x86/include/asm/paravirt.h:756 [inline] kcsan_setup_watchpoint+0x1d4/0x460 kernel/kcsan/core.c:436 check_access kernel/kcsan/core.c:466 [inline] __tsan_read1 kernel/kcsan/core.c:593 [inline] __tsan_read1+0xc2/0x100 kernel/kcsan/core.c:593 kallsyms_expand_symbol.constprop.0+0x70/0x160 kernel/kallsyms.c:79 kallsyms_lookup_name+0x7f/0x120 kernel/kallsyms.c:170 insert_report_filterlist kernel/kcsan/debugfs.c:155 [inline] debugfs_write+0x14b/0x2d0 kernel/kcsan/debugfs.c:256 full_proxy_write+0xbd/0x100 fs/debugfs/file.c:225 __vfs_write+0x67/0xc0 fs/read_write.c:494 vfs_write fs/read_write.c:558 [inline] vfs_write+0x18a/0x390 fs/read_write.c:542 ksys_write+0xd5/0x1b0 fs/read_write.c:611 __do_sys_write fs/read_write.c:623 [inline] __se_sys_write fs/read_write.c:620 [inline] __x64_sys_write+0x4c/0x60 fs/read_write.c:620 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 read to 0xffffffff8603d008 of 8 bytes by task 0 on cpu 0: tick_do_update_jiffies64+0x2b/0x250 kernel/time/tick-sched.c:62 tick_nohz_update_jiffies kernel/time/tick-sched.c:505 [inline] tick_nohz_irq_enter kernel/time/tick-sched.c:1257 [inline] tick_irq_enter+0x139/0x1c0 kernel/time/tick-sched.c:1274 irq_enter+0x4f/0x60 kernel/softirq.c:354 entering_irq arch/x86/include/asm/apic.h:517 [inline] entering_ack_irq arch/x86/include/asm/apic.h:523 [inline] smp_apic_timer_interrupt+0x55/0x280 arch/x86/kernel/apic/apic.c:1133 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830 native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:571 default_idle_call+0x1e/0x40 kernel/sched/idle.c:94 cpuidle_idle_call kernel/sched/idle.c:154 [inline] do_idle+0x1af/0x280 kernel/sched/idle.c:263 cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:355 rest_init+0xec/0xf6 init/main.c:452 arch_call_rest_init+0x17/0x37 start_kernel+0x838/0x85e init/main.c:786 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:490 x86_64_start_kernel+0x72/0x76 arch/x86/kernel/head64.c:471 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:241 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.4.0-rc7+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Use READ_ONCE() and WRITE_ONCE() to annotate this expected race. Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20191205045619.204946-1-edumazet@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-23bpf: Fix incorrect verifier simulation of ARSH under ALU32Daniel Borkmann
commit 0af2ffc93a4b50948f9dad2786b7f1bd253bf0b9 upstream. Anatoly has been fuzzing with kBdysch harness and reported a hang in one of the outcomes: 0: R1=ctx(id=0,off=0,imm=0) R10=fp0 0: (85) call bpf_get_socket_cookie#46 1: R0_w=invP(id=0) R10=fp0 1: (57) r0 &= 808464432 2: R0_w=invP(id=0,umax_value=808464432,var_off=(0x0; 0x30303030)) R10=fp0 2: (14) w0 -= 810299440 3: R0_w=invP(id=0,umax_value=4294967295,var_off=(0xcf800000; 0x3077fff0)) R10=fp0 3: (c4) w0 s>>= 1 4: R0_w=invP(id=0,umin_value=1740636160,umax_value=2147221496,var_off=(0x67c00000; 0x183bfff8)) R10=fp0 4: (76) if w0 s>= 0x30303030 goto pc+216 221: R0_w=invP(id=0,umin_value=1740636160,umax_value=2147221496,var_off=(0x67c00000; 0x183bfff8)) R10=fp0 221: (95) exit processed 6 insns (limit 1000000) [...] Taking a closer look, the program was xlated as follows: # ./bpftool p d x i 12 0: (85) call bpf_get_socket_cookie#7800896 1: (bf) r6 = r0 2: (57) r6 &= 808464432 3: (14) w6 -= 810299440 4: (c4) w6 s>>= 1 5: (76) if w6 s>= 0x30303030 goto pc+216 6: (05) goto pc-1 7: (05) goto pc-1 8: (05) goto pc-1 [...] 220: (05) goto pc-1 221: (05) goto pc-1 222: (95) exit Meaning, the visible effect is very similar to f54c7898ed1c ("bpf: Fix precision tracking for unbounded scalars"), that is, the fall-through branch in the instruction 5 is considered to be never taken given the conclusion from the min/max bounds tracking in w6, and therefore the dead-code sanitation rewrites it as goto pc-1. However, real-life input disagrees with verification analysis since a soft-lockup was observed. The bug sits in the analysis of the ARSH. The definition is that we shift the target register value right by K bits through shifting in copies of its sign bit. In adjust_scalar_min_max_vals(), we do first coerce the register into 32 bit mode, same happens after simulating the operation. However, for the case of simulating the actual ARSH, we don't take the mode into account and act as if it's always 64 bit, but location of sign bit is different: dst_reg->smin_value >>= umin_val; dst_reg->smax_value >>= umin_val; dst_reg->var_off = tnum_arshift(dst_reg->var_off, umin_val); Consider an unknown R0 where bpf_get_socket_cookie() (or others) would for example return 0xffff. With the above ARSH simulation, we'd see the following results: [...] 1: R1=ctx(id=0,off=0,imm=0) R2_w=invP65535 R10=fp0 1: (85) call bpf_get_socket_cookie#46 2: R0_w=invP(id=0) R10=fp0 2: (57) r0 &= 808464432 -> R0_runtime = 0x3030 3: R0_w=invP(id=0,umax_value=808464432,var_off=(0x0; 0x30303030)) R10=fp0 3: (14) w0 -= 810299440 -> R0_runtime = 0xcfb40000 4: R0_w=invP(id=0,umax_value=4294967295,var_off=(0xcf800000; 0x3077fff0)) R10=fp0 (0xffffffff) 4: (c4) w0 s>>= 1 -> R0_runtime = 0xe7da0000 5: R0_w=invP(id=0,umin_value=1740636160,umax_value=2147221496,var_off=(0x67c00000; 0x183bfff8)) R10=fp0 (0x67c00000) (0x7ffbfff8) [...] In insn 3, we have a runtime value of 0xcfb40000, which is '1100 1111 1011 0100 0000 0000 0000 0000', the result after the shift has 0xe7da0000 that is '1110 0111 1101 1010 0000 0000 0000 0000', where the sign bit is correctly retained in 32 bit mode. In insn4, the umax was 0xffffffff, and changed into 0x7ffbfff8 after the shift, that is, '0111 1111 1111 1011 1111 1111 1111 1000' and means here that the simulation didn't retain the sign bit. With above logic, the updates happen on the 64 bit min/max bounds and given we coerced the register, the sign bits of the bounds are cleared as well, meaning, we need to force the simulation into s32 space for 32 bit alu mode. Verification after the fix below. We're first analyzing the fall-through branch on 32 bit signed >= test eventually leading to rejection of the program in this specific case: 0: R1=ctx(id=0,off=0,imm=0) R10=fp0 0: (b7) r2 = 808464432 1: R1=ctx(id=0,off=0,imm=0) R2_w=invP808464432 R10=fp0 1: (85) call bpf_get_socket_cookie#46 2: R0_w=invP(id=0) R10=fp0 2: (bf) r6 = r0 3: R0_w=invP(id=0) R6_w=invP(id=0) R10=fp0 3: (57) r6 &= 808464432 4: R0_w=invP(id=0) R6_w=invP(id=0,umax_value=808464432,var_off=(0x0; 0x30303030)) R10=fp0 4: (14) w6 -= 810299440 5: R0_w=invP(id=0) R6_w=invP(id=0,umax_value=4294967295,var_off=(0xcf800000; 0x3077fff0)) R10=fp0 5: (c4) w6 s>>= 1 6: R0_w=invP(id=0) R6_w=invP(id=0,umin_value=3888119808,umax_value=4294705144,var_off=(0xe7c00000; 0x183bfff8)) R10=fp0 (0x67c00000) (0xfffbfff8) 6: (76) if w6 s>= 0x30303030 goto pc+216 7: R0_w=invP(id=0) R6_w=invP(id=0,umin_value=3888119808,umax_value=4294705144,var_off=(0xe7c00000; 0x183bfff8)) R10=fp0 7: (30) r0 = *(u8 *)skb[808464432] BPF_LD_[ABS|IND] uses reserved fields processed 8 insns (limit 1000000) [...] Fixes: 9cbe1f5a32dc ("bpf/verifier: improve register value range tracking with ARSH") Reported-by: Anatoly Trosinenko <anatoly.trosinenko@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200115204733.16648-1-daniel@iogearbox.net Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-23locking/lockdep: Fix buffer overrun problem in stack_trace[]Waiman Long
commit d91f3057263ceb691ef527e71b41a56b17f6c869 upstream. If the lockdep code is really running out of the stack_trace entries, it is likely that buffer overrun can happen and the data immediately after stack_trace[] will be corrupted. If there is less than LOCK_TRACE_SIZE_IN_LONGS entries left before the call to save_trace(), the max_entries computation will leave it with a very large positive number because of its unsigned nature. The subsequent call to stack_trace_save() will then corrupt the data after stack_trace[]. Fix that by changing max_entries to a signed integer and check for negative value before calling stack_trace_save(). Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 12593b7467f9 ("locking/lockdep: Reduce space occupied by stack traces") Link: https://lkml.kernel.org/r/20191220135128.14876-1-longman@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-23locking/rwsem: Fix kernel crash when spinning on RWSEM_OWNER_UNKNOWNWaiman Long
commit 39e7234f00bc93613c086ae42d852d5f4147120a upstream. The commit 91d2a812dfb9 ("locking/rwsem: Make handoff writer optimistically spin on owner") will allow a recently woken up waiting writer to spin on the owner. Unfortunately, if the owner happens to be RWSEM_OWNER_UNKNOWN, the code will incorrectly spin on it leading to a kernel crash. This is fixed by passing the proper non-spinnable bits to rwsem_spin_on_owner() so that RWSEM_OWNER_UNKNOWN will be treated as a non-spinnable target. Fixes: 91d2a812dfb9 ("locking/rwsem: Make handoff writer optimistically spin on owner") Reported-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Christoph Hellwig <hch@lst.de> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20200115154336.8679-1-longman@redhat.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-23cpu/SMT: Fix x86 link error without CONFIG_SYSFSArnd Bergmann
commit dc8d37ed304eeeea47e65fb9edc1c6c8b0093386 upstream. When CONFIG_SYSFS is disabled, but CONFIG_HOTPLUG_SMT is enabled, the kernel fails to link: arch/x86/power/cpu.o: In function `hibernate_resume_nonboot_cpu_disable': (.text+0x38d): undefined reference to `cpuhp_smt_enable' arch/x86/power/hibernate.o: In function `arch_resume_nosmt': hibernate.c:(.text+0x291): undefined reference to `cpuhp_smt_enable' hibernate.c:(.text+0x29c): undefined reference to `cpuhp_smt_disable' Move the exported functions out of the #ifdef section into its own with the correct conditions. The patch that caused this is marked for stable backports, so this one may need to be backported as well. Fixes: ec527c318036 ("x86/power: Fix 'nosmt' vs hibernation triple fault during resume") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Jiri Kosina <jkosina@suse.cz> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20191210195614.786555-1-arnd@arndb.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-23ptrace: reintroduce usage of subjective credentials in ptrace_has_cap()Christian Brauner
commit 6b3ad6649a4c75504edeba242d3fd36b3096a57f upstream. Commit 69f594a38967 ("ptrace: do not audit capability check when outputing /proc/pid/stat") introduced the ability to opt out of audit messages for accesses to various proc files since they are not violations of policy. While doing so it somehow switched the check from ns_capable() to has_ns_capability{_noaudit}(). That means it switched from checking the subjective credentials of the task to using the objective credentials. This is wrong since. ptrace_has_cap() is currently only used in ptrace_may_access() And is used to check whether the calling task (subject) has the CAP_SYS_PTRACE capability in the provided user namespace to operate on the target task (object). According to the cred.h comments this would mean the subjective credentials of the calling task need to be used. This switches ptrace_has_cap() to use security_capable(). Because we only call ptrace_has_cap() in ptrace_may_access() and in there we already have a stable reference to the calling task's creds under rcu_read_lock() there's no need to go through another series of dereferences and rcu locking done in ns_capable{_noaudit}(). As one example where this might be particularly problematic, Jann pointed out that in combination with the upcoming IORING_OP_OPENAT feature, this bug might allow unprivileged users to bypass the capability checks while asynchronously opening files like /proc/*/mem, because the capability checks for this would be performed against kernel credentials. To illustrate on the former point about this being exploitable: When io_uring creates a new context it records the subjective credentials of the caller. Later on, when it starts to do work it creates a kernel thread and registers a callback. The callback runs with kernel creds for ktask->real_cred and ktask->cred. To prevent this from becoming a full-blown 0-day io_uring will call override_cred() and override ktask->cred with the subjective credentials of the creator of the io_uring instance. With ptrace_has_cap() currently looking at ktask->real_cred this override will be ineffective and the caller will be able to open arbitray proc files as mentioned above. Luckily, this is currently not exploitable but will turn into a 0-day once IORING_OP_OPENAT{2} land in v5.6. Fix it now! Cc: Oleg Nesterov <oleg@redhat.com> Cc: Eric Paris <eparis@redhat.com> Cc: stable@vger.kernel.org Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Jann Horn <jannh@google.com> Fixes: 69f594a38967 ("ptrace: do not audit capability check when outputing /proc/pid/stat") Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-23perf: Correctly handle failed perf_get_aux_event()Mark Rutland
commit da9ec3d3dd0f1240a48920be063448a2242dbd90 upstream. Vince reports a worrying issue: | so I was tracking down some odd behavior in the perf_fuzzer which turns | out to be because perf_even_open() sometimes returns 0 (indicating a file | descriptor of 0) even though as far as I can tell stdin is still open. ... and further the cause: | error is triggered if aux_sample_size has non-zero value. | | seems to be this line in kernel/events/core.c: | | if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader)) | goto err_locked; | | (note, err is never set) This seems to be a thinko in commit: ab43762ef010967e ("perf: Allow normal events to output AUX data") ... and we should probably return -EINVAL here, as this should only happen when the new event is mis-configured or does not have a compatible aux_event group leader. Fixes: ab43762ef010967e ("perf: Allow normal events to output AUX data") Reported-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Tested-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-17keys: Fix request_key() cacheDavid Howells
commit 8379bb84be757d5df2d818509faec5d66adb861d upstream. When the key cached by request_key() and co. is cleaned up on exit(), the code looks in the wrong task_struct, and so clears the wrong cache. This leads to anomalies in key refcounting when doing, say, a kernel build on an afs volume, that then trigger kasan to report a use-after-free when the key is viewed in /proc/keys. Fix this by making exit_creds() look in the passed-in task_struct rather than in current (the task_struct cleanup code is deferred by RCU and potentially run in another task). Fixes: 7743c48e54ee ("keys: Cache result of request_key*() temporarily in task_struct") Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-17bpf: Make use of probe_user_write in probe write helperDaniel Borkmann
commit eb1b66887472eaa7342305b7890ae510dd9d1a79 upstream. Convert the bpf_probe_write_user() helper to probe_user_write() such that writes are not attempted under KERNEL_DS anymore which is buggy as kernel and user space pointers can have overlapping addresses. Also, given we have the access_ok() check inside probe_user_write(), the helper doesn't need to do it twice. Fixes: 96ae52279594 ("bpf: Add bpf_probe_write_user BPF helper to be called in tracers") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/841c461781874c07a0ee404a454c3bc0459eed30.1572649915.git.daniel@iogearbox.net Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-17bpf: cgroup: prevent out-of-order release of cgroup bpfRoman Gushchin
commit e10360f815ca6367357b2c2cfef17fc663e50f7b upstream. Before commit 4bfc0bb2c60e ("bpf: decouple the lifetime of cgroup_bpf from cgroup itself") cgroup bpf structures were released with corresponding cgroup structures. It guaranteed the hierarchical order of destruction: children were always first. It preserved attached programs from being released before their propagated copies. But with cgroup auto-detachment there are no such guarantees anymore: cgroup bpf is released as soon as the cgroup is offline and there are no live associated sockets. It means that an attached program can be detached and released, while its propagated copy is still living in the cgroup subtree. This will obviously lead to an use-after-free bug. To reproduce the issue the following script can be used: #!/bin/bash CGROOT=/sys/fs/cgroup mkdir -p ${CGROOT}/A ${CGROOT}/B ${CGROOT}/A/C sleep 1 ./test_cgrp2_attach ${CGROOT}/A egress & A_PID=$! ./test_cgrp2_attach ${CGROOT}/B egress & B_PID=$! echo $$ > ${CGROOT}/A/C/cgroup.procs iperf -s & S_PID=$! iperf -c localhost -t 100 & C_PID=$! sleep 1 echo $$ > ${CGROOT}/B/cgroup.procs echo ${S_PID} > ${CGROOT}/B/cgroup.procs echo ${C_PID} > ${CGROOT}/B/cgroup.procs sleep 1 rmdir ${CGROOT}/A/C rmdir ${CGROOT}/A sleep 1 kill -9 ${S_PID} ${C_PID} ${A_PID} ${B_PID} On the unpatched kernel the following stacktrace can be obtained: [ 33.619799] BUG: unable to handle page fault for address: ffffbdb4801ab002 [ 33.620677] #PF: supervisor read access in kernel mode [ 33.621293] #PF: error_code(0x0000) - not-present page [ 33.622754] Oops: 0000 [#1] SMP NOPTI [ 33.623202] CPU: 0 PID: 601 Comm: iperf Not tainted 5.5.0-rc2+ #23 [ 33.625545] RIP: 0010:__cgroup_bpf_run_filter_skb+0x29f/0x3d0 [ 33.635809] Call Trace: [ 33.636118] ? __cgroup_bpf_run_filter_skb+0x2bf/0x3d0 [ 33.636728] ? __switch_to_asm+0x40/0x70 [ 33.637196] ip_finish_output+0x68/0xa0 [ 33.637654] ip_output+0x76/0xf0 [ 33.638046] ? __ip_finish_output+0x1c0/0x1c0 [ 33.638576] __ip_queue_xmit+0x157/0x410 [ 33.639049] __tcp_transmit_skb+0x535/0xaf0 [ 33.639557] tcp_write_xmit+0x378/0x1190 [ 33.640049] ? _copy_from_iter_full+0x8d/0x260 [ 33.640592] tcp_sendmsg_locked+0x2a2/0xdc0 [ 33.641098] ? sock_has_perm+0x10/0xa0 [ 33.641574] tcp_sendmsg+0x28/0x40 [ 33.641985] sock_sendmsg+0x57/0x60 [ 33.642411] sock_write_iter+0x97/0x100 [ 33.642876] new_sync_write+0x1b6/0x1d0 [ 33.643339] vfs_write+0xb6/0x1a0 [ 33.643752] ksys_write+0xa7/0xe0 [ 33.644156] do_syscall_64+0x5b/0x1b0 [ 33.644605] entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fix this by grabbing a reference to the bpf structure of each ancestor on the initialization of the cgroup bpf structure, and dropping the reference at the end of releasing the cgroup bpf structure. This will restore the hierarchical order of cgroup bpf releasing, without adding any operations on hot paths. Thanks to Josef Bacik for the debugging and the initial analysis of the problem. Fixes: 4bfc0bb2c60e ("bpf: decouple the lifetime of cgroup_bpf from cgroup itself") Reported-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Roman Gushchin <guro@fb.com> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-14clone3: ensure copy_thread_tls is implementedAmanieu d'Antras
commit dd499f7a7e34270208350a849ef103c0b3ae477f upstream. copy_thread implementations handle CLONE_SETTLS by reading the TLS value from the registers containing the syscall arguments for clone. This doesn't work with clone3 since the TLS value is passed in clone_args instead. Signed-off-by: Amanieu d'Antras <amanieu@gmail.com> Cc: <stable@vger.kernel.org> # 5.3.x Link: https://lore.kernel.org/r/20200102172413.654385-8-amanieu@gmail.com Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-14tracing: Have stack tracer compile when MCOUNT_INSN_SIZE is not definedSteven Rostedt (VMware)
commit b8299d362d0837ae39e87e9019ebe6b736e0f035 upstream. On some archs with some configurations, MCOUNT_INSN_SIZE is not defined, and this makes the stack tracer fail to compile. Just define it to zero in this case. Link: https://lore.kernel.org/r/202001020219.zvE3vsty%lkp@intel.com Cc: stable@vger.kernel.org Fixes: 4df297129f622 ("tracing: Remove most or all of stack tracer stack size from stack_max_size") Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-14kernel/trace: Fix do not unregister tracepoints when register ↵Kaitao Cheng
sched_migrate_task fail commit 50f9ad607ea891a9308e67b81f774c71736d1098 upstream. In the function, if register_trace_sched_migrate_task() returns error, sched_switch/sched_wakeup_new/sched_wakeup won't unregister. That is why fail_deprobe_sched_switch was added. Link: http://lkml.kernel.org/r/20191231133530.2794-1-pilgrimtao@gmail.com Cc: stable@vger.kernel.org Fixes: 478142c39c8c2 ("tracing: do not grab lock in wakeup latency function tracing") Signed-off-by: Kaitao Cheng <pilgrimtao@gmail.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-12tracing: Do not create directories if lockdown is in affectSteven Rostedt (VMware)
commit a356646a56857c2e5ad875beec734d7145ecd49a upstream. If lockdown is disabling tracing on boot up, it prevents the tracing files from even bering created. But when that happens, there's several places that will give a warning that the files were not created as that is usually a sign of a bug. Add in strategic locations where a check is made to see if tracing is disabled by lockdown, and if it is, do not go further, and fail silently (but print that tracing is disabled by lockdown, without doing a WARN_ON()). Cc: Matthew Garrett <mjg59@google.com> Fixes: 17911ff38aa5 ("tracing: Add locked_down checks to the open calls of files created for tracefs") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>