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2020-09-17kprobes: Fix compiler warning for !CONFIG_KPROBES_ON_FTRACEMuchun Song
commit 10de795a5addd1962406796a6e13ba6cc0fc6bee upstream. Fix compiler warning(as show below) for !CONFIG_KPROBES_ON_FTRACE. kernel/kprobes.c: In function 'kill_kprobe': kernel/kprobes.c:1116:33: warning: statement with no effect [-Wunused-value] 1116 | #define disarm_kprobe_ftrace(p) (-ENODEV) | ^ kernel/kprobes.c:2154:3: note: in expansion of macro 'disarm_kprobe_ftrace' 2154 | disarm_kprobe_ftrace(p); Link: https://lore.kernel.org/r/20200805142136.0331f7ea@canb.auug.org.au Link: https://lkml.kernel.org/r/20200805172046.19066-1-songmuchun@bytedance.com Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Fixes: 0cb2f1372baa ("kprobes: Fix NULL pointer dereference at kprobe_ftrace_handler") Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-09-17kprobes: Fix NULL pointer dereference at kprobe_ftrace_handlerMuchun Song
commit 0cb2f1372baa60af8456388a574af6133edd7d80 upstream. We found a case of kernel panic on our server. The stack trace is as follows(omit some irrelevant information): BUG: kernel NULL pointer dereference, address: 0000000000000080 RIP: 0010:kprobe_ftrace_handler+0x5e/0xe0 RSP: 0018:ffffb512c6550998 EFLAGS: 00010282 RAX: 0000000000000000 RBX: ffff8e9d16eea018 RCX: 0000000000000000 RDX: ffffffffbe1179c0 RSI: ffffffffc0535564 RDI: ffffffffc0534ec0 RBP: ffffffffc0534ec1 R08: ffff8e9d1bbb0f00 R09: 0000000000000004 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: ffff8e9d1f797060 R14: 000000000000bacc R15: ffff8e9ce13eca00 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000080 CR3: 00000008453d0005 CR4: 00000000003606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <IRQ> ftrace_ops_assist_func+0x56/0xe0 ftrace_call+0x5/0x34 tcpa_statistic_send+0x5/0x130 [ttcp_engine] The tcpa_statistic_send is the function being kprobed. After analysis, the root cause is that the fourth parameter regs of kprobe_ftrace_handler is NULL. Why regs is NULL? We use the crash tool to analyze the kdump. crash> dis tcpa_statistic_send -r <tcpa_statistic_send>: callq 0xffffffffbd8018c0 <ftrace_caller> The tcpa_statistic_send calls ftrace_caller instead of ftrace_regs_caller. So it is reasonable that the fourth parameter regs of kprobe_ftrace_handler is NULL. In theory, we should call the ftrace_regs_caller instead of the ftrace_caller. After in-depth analysis, we found a reproducible path. Writing a simple kernel module which starts a periodic timer. The timer's handler is named 'kprobe_test_timer_handler'. The module name is kprobe_test.ko. 1) insmod kprobe_test.ko 2) bpftrace -e 'kretprobe:kprobe_test_timer_handler {}' 3) echo 0 > /proc/sys/kernel/ftrace_enabled 4) rmmod kprobe_test 5) stop step 2) kprobe 6) insmod kprobe_test.ko 7) bpftrace -e 'kretprobe:kprobe_test_timer_handler {}' We mark the kprobe as GONE but not disarm the kprobe in the step 4). The step 5) also do not disarm the kprobe when unregister kprobe. So we do not remove the ip from the filter. In this case, when the module loads again in the step 6), we will replace the code to ftrace_caller via the ftrace_module_enable(). When we register kprobe again, we will not replace ftrace_caller to ftrace_regs_caller because the ftrace is disabled in the step 3). So the step 7) will trigger kernel panic. Fix this problem by disarming the kprobe when the module is going away. Link: https://lkml.kernel.org/r/20200728064536.24405-1-songmuchun@bytedance.com Cc: stable@vger.kernel.org Fixes: ae6aa16fdc16 ("kprobes: introduce ftrace based optimization") Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Muchun Song <songmuchun@bytedance.com> Co-developed-by: Chengming Zhou <zhouchengming@bytedance.com> Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-08-03kprobes: Do not expose probe addresses to non-CAP_SYSLOGKees Cook
commit 60f7bb66b88b649433bf700acfc60c3f24953871 upstream. The kprobe show() functions were using "current"'s creds instead of the file opener's creds for kallsyms visibility. Fix to use seq_file->file->f_cred. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: stable@vger.kernel.org Fixes: 81365a947de4 ("kprobes: Show address of kprobes if kallsyms does") Fixes: ffb9bd68ebdb ("kprobes: Show blacklist addresses as same as kallsyms does") Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-08-03kallsyms: Refactor kallsyms_show_value() to take credKees Cook
commit 160251842cd35a75edfb0a1d76afa3eb674ff40a upstream. In order to perform future tests against the cred saved during open(), switch kallsyms_show_value() to operate on a cred, and have all current callers pass current_cred(). This makes it very obvious where callers are checking the wrong credential in their "read" contexts. These will be fixed in the coming patches. Additionally switch return value to bool, since it is always used as a direct permission check, not a 0-on-success, negative-on-error style function return. Cc: stable@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-07-16kprobes: Suppress the suspicious RCU warning on kprobesMasami Hiramatsu
commit 6743ad432ec92e680cd0d9db86cb17b949cf5a43 upstream. Anders reported that the lockdep warns that suspicious RCU list usage in register_kprobe() (detected by CONFIG_PROVE_RCU_LIST.) This is because get_kprobe() access kprobe_table[] by hlist_for_each_entry_rcu() without rcu_read_lock. If we call get_kprobe() from the breakpoint handler context, it is run with preempt disabled, so this is not a problem. But in other cases, instead of rcu_read_lock(), we locks kprobe_mutex so that the kprobe_table[] is not updated. So, current code is safe, but still not good from the view point of RCU. Joel suggested that we can silent that warning by passing lockdep_is_held() to the last argument of hlist_for_each_entry_rcu(). Add lockdep_is_held(&kprobe_mutex) at the end of the hlist_for_each_entry_rcu() to suppress the warning. Link: http://lkml.kernel.org/r/158927055350.27680.10261450713467997503.stgit@devnote2 Reported-by: Anders Roxell <anders.roxell@linaro.org> Suggested-by: Joel Fernandes <joel@joelfernandes.org> Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-07-13kretprobe: Prevent triggering kretprobe from within kprobe_flush_taskJiri Olsa
commit 9b38cc704e844e41d9cf74e647bff1d249512cb3 upstream. Ziqian reported lockup when adding retprobe on _raw_spin_lock_irqsave. My test was also able to trigger lockdep output: ============================================ WARNING: possible recursive locking detected 5.6.0-rc6+ #6 Not tainted -------------------------------------------- sched-messaging/2767 is trying to acquire lock: ffffffff9a492798 (&(kretprobe_table_locks[i].lock)){-.-.}, at: kretprobe_hash_lock+0x52/0xa0 but task is already holding lock: ffffffff9a491a18 (&(kretprobe_table_locks[i].lock)){-.-.}, at: kretprobe_trampoline+0x0/0x50 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&(kretprobe_table_locks[i].lock)); lock(&(kretprobe_table_locks[i].lock)); *** DEADLOCK *** May be due to missing lock nesting notation 1 lock held by sched-messaging/2767: #0: ffffffff9a491a18 (&(kretprobe_table_locks[i].lock)){-.-.}, at: kretprobe_trampoline+0x0/0x50 stack backtrace: CPU: 3 PID: 2767 Comm: sched-messaging Not tainted 5.6.0-rc6+ #6 Call Trace: dump_stack+0x96/0xe0 __lock_acquire.cold.57+0x173/0x2b7 ? native_queued_spin_lock_slowpath+0x42b/0x9e0 ? lockdep_hardirqs_on+0x590/0x590 ? __lock_acquire+0xf63/0x4030 lock_acquire+0x15a/0x3d0 ? kretprobe_hash_lock+0x52/0xa0 _raw_spin_lock_irqsave+0x36/0x70 ? kretprobe_hash_lock+0x52/0xa0 kretprobe_hash_lock+0x52/0xa0 trampoline_handler+0xf8/0x940 ? kprobe_fault_handler+0x380/0x380 ? find_held_lock+0x3a/0x1c0 kretprobe_trampoline+0x25/0x50 ? lock_acquired+0x392/0xbc0 ? _raw_spin_lock_irqsave+0x50/0x70 ? __get_valid_kprobe+0x1f0/0x1f0 ? _raw_spin_unlock_irqrestore+0x3b/0x40 ? finish_task_switch+0x4b9/0x6d0 ? __switch_to_asm+0x34/0x70 ? __switch_to_asm+0x40/0x70 The code within the kretprobe handler checks for probe reentrancy, so we won't trigger any _raw_spin_lock_irqsave probe in there. The problem is in outside kprobe_flush_task, where we call: kprobe_flush_task kretprobe_table_lock raw_spin_lock_irqsave _raw_spin_lock_irqsave where _raw_spin_lock_irqsave triggers the kretprobe and installs kretprobe_trampoline handler on _raw_spin_lock_irqsave return. The kretprobe_trampoline handler is then executed with already locked kretprobe_table_locks, and first thing it does is to lock kretprobe_table_locks ;-) the whole lockup path like: kprobe_flush_task kretprobe_table_lock raw_spin_lock_irqsave _raw_spin_lock_irqsave ---> probe triggered, kretprobe_trampoline installed ---> kretprobe_table_locks locked kretprobe_trampoline trampoline_handler kretprobe_hash_lock(current, &head, &flags); <--- deadlock Adding kprobe_busy_begin/end helpers that mark code with fake probe installed to prevent triggering of another kprobe within this code. Using these helpers in kprobe_flush_task, so the probe recursion protection check is hit and the probe is never set to prevent above lockup. Link: http://lkml.kernel.org/r/158927059835.27680.7011202830041561604.stgit@devnote2 Fixes: ef53d9c5e4da ("kprobes: improve kretprobe scalability with hashed locking") Cc: Ingo Molnar <mingo@kernel.org> Cc: "Gustavo A . R . Silva" <gustavoars@kernel.org> Cc: Anders Roxell <anders.roxell@linaro.org> Cc: "Naveen N . Rao" <naveen.n.rao@linux.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David Miller <davem@davemloft.net> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: stable@vger.kernel.org Reported-by: "Ziqian SUN (Zamir)" <zsun@redhat.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-07-13kprobes: Fix to protect kick_kprobe_optimizer() by kprobe_mutexMasami Hiramatsu
commit 1a0aa991a6274161c95a844c58cfb801d681eb59 upstream. In kprobe_optimizer() kick_kprobe_optimizer() is called without kprobe_mutex, but this can race with other caller which is protected by kprobe_mutex. To fix that, expand kprobe_mutex protected area to protect kick_kprobe_optimizer() call. Link: http://lkml.kernel.org/r/158927057586.27680.5036330063955940456.stgit@devnote2 Fixes: cd7ebe2298ff ("kprobes: Use text_poke_smp_batch for optimizing") Cc: Ingo Molnar <mingo@kernel.org> Cc: "Gustavo A . R . Silva" <gustavoars@kernel.org> Cc: Anders Roxell <anders.roxell@linaro.org> Cc: "Naveen N . Rao" <naveen.n.rao@linux.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David Miller <davem@davemloft.net> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ziqian SUN <zsun@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-05-15kprobes: Fix optimize_kprobe()/unoptimize_kprobe() cancellation logicMasami Hiramatsu
commit e4add247789e4ba5e08ad8256183ce2e211877d4 upstream. optimize_kprobe() and unoptimize_kprobe() cancels if a given kprobe is on the optimizing_list or unoptimizing_list already. However, since the following commit: f66c0447cca1 ("kprobes: Set unoptimized flag after unoptimizing code") modified the update timing of the KPROBE_FLAG_OPTIMIZED, it doesn't work as expected anymore. The optimized_kprobe could be in the following states: - [optimizing]: Before inserting jump instruction op.kp->flags has KPROBE_FLAG_OPTIMIZED and op->list is not empty. - [optimized]: jump inserted op.kp->flags has KPROBE_FLAG_OPTIMIZED and op->list is empty. - [unoptimizing]: Before removing jump instruction (including unused optprobe) op.kp->flags has KPROBE_FLAG_OPTIMIZED and op->list is not empty. - [unoptimized]: jump removed op.kp->flags doesn't have KPROBE_FLAG_OPTIMIZED and op->list is empty. Current code mis-expects [unoptimizing] state doesn't have KPROBE_FLAG_OPTIMIZED, and that can cause incorrect results. To fix this, introduce optprobe_queued_unopt() to distinguish [optimizing] and [unoptimizing] states and fixes the logic in optimize_kprobe() and unoptimize_kprobe(). [ mingo: Cleaned up the changelog and the code a bit. ] Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: bristot@redhat.com Fixes: f66c0447cca1 ("kprobes: Set unoptimized flag after unoptimizing code") Link: https://lkml.kernel.org/r/157840814418.7181.13478003006386303481.stgit@devnote2 Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-05-15kprobes: Set unoptimized flag after unoptimizing codeMasami Hiramatsu
commit f66c0447cca1281116224d474cdb37d6a18e4b5b upstream. Set the unoptimized flag after confirming the code is completely unoptimized. Without this fix, when a kprobe hits the intermediate modified instruction (the first byte is replaced by an INT3, but later bytes can still be a jump address operand) while unoptimizing, it can return to the middle byte of the modified code, which causes an invalid instruction exception in the kernel. Usually, this is a rare case, but if we put a probe on the function call while text patching, it always causes a kernel panic as below: # echo p text_poke+5 > kprobe_events # echo 1 > events/kprobes/enable # echo 0 > events/kprobes/enable invalid opcode: 0000 [#1] PREEMPT SMP PTI RIP: 0010:text_poke+0x9/0x50 Call Trace: arch_unoptimize_kprobe+0x22/0x28 arch_unoptimize_kprobes+0x39/0x87 kprobe_optimizer+0x6e/0x290 process_one_work+0x2a0/0x610 worker_thread+0x28/0x3d0 ? process_one_work+0x610/0x610 kthread+0x10d/0x130 ? kthread_park+0x80/0x80 ret_from_fork+0x3a/0x50 text_poke() is used for patching the code in optprobes. This can happen even if we blacklist text_poke() and other functions, because there is a small time window during which we show the intermediate code to other CPUs. [ mingo: Edited the changelog. ] Tested-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: bristot@redhat.com Fixes: 6274de4984a6 ("kprobes: Support delayed unoptimizing") Link: https://lkml.kernel.org/r/157483422375.25881.13508326028469515760.stgit@devnote2 Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2019-10-05kprobes: Prohibit probing on BUG() and WARN() addressMasami Hiramatsu
[ 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>
2019-09-10kprobes: Fix potential deadlock in kprobe_optimizer()Andrea Righi
[ 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>
2019-05-30treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156Thomas Gleixner
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 59 temple place suite 330 boston ma 02111 1307 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1334 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Richard Fontana <rfontana@redhat.com> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-04-16kprobes: Fix error check when reusing optimized probesMasami Hiramatsu
The following commit introduced a bug in one of our error paths: 819319fc9346 ("kprobes: Return error if we fail to reuse kprobe instead of BUG_ON()") it missed to handle the return value of kprobe_optready() as error-value. In reality, the kprobe_optready() returns a bool result, so "true" case must be passed instead of 0. This causes some errors on kprobe boot-time selftests on ARM: [ ] Beginning kprobe tests... [ ] Probe ARM code [ ] kprobe [ ] kretprobe [ ] ARM instruction simulation [ ] Check decoding tables [ ] Run test cases [ ] FAIL: test_case_handler not run [ ] FAIL: Test andge r10, r11, r14, asr r7 [ ] FAIL: Scenario 11 ... [ ] FAIL: Scenario 7 [ ] Total instruction simulation tests=1631, pass=1433 fail=198 [ ] kprobe tests failed This can happen if an optimized probe is unregistered and next kprobe is registered on same address until the previous probe is not reclaimed. If this happens, a hidden aggregated probe may be kept in memory, and no new kprobe can probe same address. Also, in that case register_kprobe() will return "1" instead of minus error value, which can mislead caller logic. Signed-off-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.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org # v5.0+ Fixes: 819319fc9346 ("kprobes: Return error if we fail to reuse kprobe instead of BUG_ON()") Link: http://lkml.kernel.org/r/155530808559.32517.539898325433642204.stgit@devnote2 Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-02-13kprobes: Search non-suffixed symbol in blacklistMasami Hiramatsu
Newer GCC versions can generate some different instances of a function with suffixed symbols if the function is optimized and only has a part of that. (e.g. .constprop, .part etc.) In this case, it is not enough to check the entry of kprobe blacklist because it only records non-suffixed symbol address. To fix this issue, search non-suffixed symbol in blacklist if given address is within a symbol which has a suffix. Note that this can cause false positive cases if a kprobe-safe function is optimized to suffixed instance and has same name symbol which is blacklisted. But I would like to chose a fail-safe design for this issue. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andrea Righi <righi.andrea@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/154998799234.31052.6136378903570418008.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-12-26Merge branch 'perf-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf updates from Ingo Molnar: "The main changes in this cycle on the kernel side: - rework kprobes blacklist handling (Masami Hiramatsu) - misc cleanups on the tooling side these areas were the main focus: - 'perf trace' enhancements (Arnaldo Carvalho de Melo) - 'perf bench' enhancements (Davidlohr Bueso) - 'perf record' enhancements (Alexey Budankov) - 'perf annotate' enhancements (Jin Yao) - 'perf top' enhancements (Jiri Olsa) - Intel hw tracing enhancements (Adrian Hunter) - ARM hw tracing enhancements (Leo Yan, Mathieu Poirier) - ... plus lots of other enhancements, cleanups and fixes" * 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (171 commits) tools uapi asm: Update asm-generic/unistd.h copy perf symbols: Relax checks on perf-PID.map ownership perf trace: Wire up the fadvise 'advice' table generator perf beauty: Add generator for fadvise64's 'advice' arg constants tools headers uapi: Grab a copy of fadvise.h perf beauty mmap: Print mmap's 'offset' arg in hexadecimal perf beauty mmap: Print PROT_READ before PROT_EXEC to match strace output perf trace beauty: Beautify arch_prctl()'s arguments perf trace: When showing string prefixes show prefix + ??? for unknown entries perf trace: Move strarrays to beauty.h for further reuse perf beauty: Wire up the x86_arch prctl code table generator perf beauty: Add a string table generator for x86's 'arch_prctl' codes tools include arch: Grab a copy of x86's prctl.h perf trace: Show NULL when syscall pointer args are 0 perf trace: Enclose the errno strings with () perf augmented_raw_syscalls: Copy 'access' arg as well perf trace: Add alignment spaces after the closing parens perf trace beauty: Print O_RDONLY when (flags & O_ACCMODE) == 0 perf trace: Allow asking for not suppressing common string prefixes perf trace: Add a prefix member to the strarray class ...
2018-12-17kprobes: Blacklist symbols in arch-defined prohibited areaMasami Hiramatsu
Blacklist symbols in arch-defined probe-prohibited areas. With this change, user can see all symbols which are prohibited to probe in debugfs. All archtectures which have custom prohibit areas should define its own arch_populate_kprobe_blacklist() function, but unless that, all symbols marked __kprobes are blacklisted. Reported-by: Andrea Righi <righi.andrea@gmail.com> Tested-by: Andrea Righi <righi.andrea@gmail.com> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: David S. Miller <davem@davemloft.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yonghong Song <yhs@fb.com> Link: http://lkml.kernel.org/r/154503485491.26176.15823229545155174796.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-11-27kprobes: Replace synchronize_sched() with synchronize_rcu()Paul E. McKenney
Now that synchronize_rcu() waits for preempt-disable regions of code as well as RCU read-side critical sections, synchronize_sched() can be replaced by synchronize_rcu(). This commit therefore makes this change. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com> 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> Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
2018-09-12kprobes: Don't call BUG_ON() if there is a kprobe in use on free listMasami Hiramatsu
Instead of calling BUG_ON(), if we find a kprobe in use on free kprobe list, just remove it from the list and keep it on kprobe hash list as same as other in-use kprobes. Signed-off-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.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/153666126882.21306.10738207224288507996.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-09-12kprobes: Return error if we fail to reuse kprobe instead of BUG_ON()Masami Hiramatsu
Make reuse_unused_kprobe() to return error code if it fails to reuse unused kprobe for optprobe instead of calling BUG_ON(). Signed-off-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.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/153666124040.21306.14150398706331307654.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-09-12kprobes: Remove pointless BUG_ON() from reuse_unused_kprobe()Masami Hiramatsu
Since reuse_unused_kprobe() is called when the given kprobe is unused, checking it inside again with BUG_ON() is pointless. Remove it. Signed-off-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.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/153666121154.21306.17540752948574483565.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-09-12kprobes: Remove pointless BUG_ON() from add_new_kprobe()Masami Hiramatsu
Before calling add_new_kprobe(), aggr_probe's GONE flag and kprobe GONE flag are cleared. We don't need to worry about that flag at this point. Signed-off-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.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/153666118298.21306.4915366706875652652.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-09-12kprobes: Remove pointless BUG_ON() from disarming processMasami Hiramatsu
All aggr_probes at this line are already disarmed by disable_kprobe() or checked by kprobe_disarmed(). So this BUG_ON() is pointless, remove it. Signed-off-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.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/153666115463.21306.8799008438116029806.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-06-21kprobes: Replace %p with other pointer typesMasami Hiramatsu
Replace %p with %pS or just remove it if unneeded. And use WARN_ONCE() if it is a single bug. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: David Howells <dhowells@redhat.com> Cc: David S . Miller <davem@davemloft.net> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Jon Medhurst <tixy@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Thomas Richter <tmricht@linux.ibm.com> Cc: Tobin C . Harding <me@tobin.cc> Cc: Will Deacon <will.deacon@arm.com> Cc: acme@kernel.org Cc: akpm@linux-foundation.org Cc: brueckner@linux.vnet.ibm.com Cc: linux-arch@vger.kernel.org Cc: rostedt@goodmis.org Cc: schwidefsky@de.ibm.com Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/lkml/152491899284.9916.5350534544808158621.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-06-21kprobes: Show address of kprobes if kallsyms doesMasami Hiramatsu
Show probed address in debugfs kprobe list file as same as kallsyms does. This information is used for checking kprobes are placed in the expected address. So it should be able to compared with address in kallsyms. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: David Howells <dhowells@redhat.com> Cc: David S . Miller <davem@davemloft.net> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Jon Medhurst <tixy@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Thomas Richter <tmricht@linux.ibm.com> Cc: Tobin C . Harding <me@tobin.cc> Cc: Will Deacon <will.deacon@arm.com> Cc: acme@kernel.org Cc: akpm@linux-foundation.org Cc: brueckner@linux.vnet.ibm.com Cc: linux-arch@vger.kernel.org Cc: rostedt@goodmis.org Cc: schwidefsky@de.ibm.com Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/lkml/152491896256.9916.1583733714492565296.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-06-21kprobes: Show blacklist addresses as same as kallsyms doesMasami Hiramatsu
Show kprobes blacklist addresses under same condition of showing kallsyms addresses. Since there are several name conflict for local symbols, kprobe blacklist needs to show each addresses so that user can identify where is on blacklist by comparing with kallsyms. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: David Howells <dhowells@redhat.com> Cc: David S . Miller <davem@davemloft.net> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Jon Medhurst <tixy@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Thomas Richter <tmricht@linux.ibm.com> Cc: Tobin C . Harding <me@tobin.cc> Cc: Will Deacon <will.deacon@arm.com> Cc: acme@kernel.org Cc: akpm@linux-foundation.org Cc: brueckner@linux.vnet.ibm.com Cc: linux-arch@vger.kernel.org Cc: rostedt@goodmis.org Cc: schwidefsky@de.ibm.com Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/lkml/152491893217.9916.14760965896164273464.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-06-21kprobes: Make list and blacklist root user read onlyMasami Hiramatsu
Since the blacklist and list files on debugfs indicates a sensitive address information to reader, it should be restricted to the root user. Suggested-by: Thomas Richter <tmricht@linux.ibm.com> Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: David Howells <dhowells@redhat.com> Cc: David S . Miller <davem@davemloft.net> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Jon Medhurst <tixy@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tobin C . Harding <me@tobin.cc> Cc: Will Deacon <will.deacon@arm.com> Cc: acme@kernel.org Cc: akpm@linux-foundation.org Cc: brueckner@linux.vnet.ibm.com Cc: linux-arch@vger.kernel.org Cc: rostedt@goodmis.org Cc: schwidefsky@de.ibm.com Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/lkml/152491890171.9916.5183693615601334087.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-06-21kprobes: Don't check the ->break_handler() in generic kprobes codeMasami Hiramatsu
Don't check the ->break_handler() from the core kprobes code, because it was only used by jprobes which got removed. ( In followup patches we'll remove the remaining calls in low level arch handlers as well and remove the callback altogether. ) Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: linux-arch@vger.kernel.org Link: https://lore.kernel.org/lkml/152942462686.15209.6324404940493598980.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-06-21kprobes: Remove jprobe API implementationMasami Hiramatsu
Remove functionally empty jprobe API implementations and test cases. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: linux-arch@vger.kernel.org Link: https://lore.kernel.org/lkml/152942430705.15209.2307050500995264322.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-04-25kprobes: Fix random address output of blacklist fileThomas Richter
File /sys/kernel/debug/kprobes/blacklist displays random addresses: [root@s8360046 linux]# cat /sys/kernel/debug/kprobes/blacklist 0x0000000047149a90-0x00000000bfcb099a print_type_x8 .... This breaks 'perf probe' which uses the blacklist file to prohibit probes on certain functions by checking the address range. Fix this by printing the correct (unhashed) address. The file mode is read all but this is not an issue as the file hierarchy points out: # ls -ld /sys/ /sys/kernel/ /sys/kernel/debug/ /sys/kernel/debug/kprobes/ /sys/kernel/debug/kprobes/blacklist dr-xr-xr-x 12 root root 0 Apr 19 07:56 /sys/ drwxr-xr-x 8 root root 0 Apr 19 07:56 /sys/kernel/ drwx------ 16 root root 0 Apr 19 06:56 /sys/kernel/debug/ drwxr-xr-x 2 root root 0 Apr 19 06:56 /sys/kernel/debug/kprobes/ -r--r--r-- 1 root root 0 Apr 19 06:56 /sys/kernel/debug/kprobes/blacklist Everything in and below /sys/kernel/debug is rwx to root only, no group or others have access. Background: Directory /sys/kernel/debug/kprobes is created by debugfs_create_dir() which sets the mode bits to rwxr-xr-x. Maybe change that to use the parent's directory mode bits instead? Link: http://lkml.kernel.org/r/20180419105556.86664-1-tmricht@linux.ibm.com Fixes: ad67b74d2469 ("printk: hash addresses printed with %p") Cc: stable@vger.kernel.org Cc: <stable@vger.kernel.org> # v4.15+ Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David S Miller <davem@davemloft.net> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: acme@kernel.org Signed-off-by: Thomas Richter <tmricht@linux.ibm.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-02-16kprobes: Propagate error from disarm_kprobe_ftrace()Jessica Yu
Improve error handling when disarming ftrace-based kprobes. Like with arm_kprobe_ftrace(), propagate any errors from disarm_kprobe_ftrace() so that we do not disable/unregister kprobes that are still armed. In other words, unregister_kprobe() and disable_kprobe() should not report success if the kprobe could not be disarmed. disarm_all_kprobes() keeps its current behavior and attempts to disarm all kprobes. It returns the last encountered error and gives a warning if not all probes could be disarmed. This patch is based on Petr Mladek's original patchset (patches 2 and 3) back in 2015, which improved kprobes error handling, found here: https://lkml.org/lkml/2015/2/26/452 However, further work on this had been paused since then and the patches were not upstreamed. Based-on-patches-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jessica Yu <jeyu@kernel.org> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David S . Miller <davem@davemloft.net> Cc: Jiri Kosina <jikos@kernel.org> Cc: Joe Lawrence <joe.lawrence@redhat.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Miroslav Benes <mbenes@suse.cz> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: live-patching@vger.kernel.org Link: http://lkml.kernel.org/r/20180109235124.30886-3-jeyu@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-02-16kprobes: Propagate error from arm_kprobe_ftrace()Jessica Yu
Improve error handling when arming ftrace-based kprobes. Specifically, if we fail to arm a ftrace-based kprobe, register_kprobe()/enable_kprobe() should report an error instead of success. Previously, this has lead to confusing situations where register_kprobe() would return 0 indicating success, but the kprobe would not be functional if ftrace registration during the kprobe arming process had failed. We should therefore take any errors returned by ftrace into account and propagate this error so that we do not register/enable kprobes that cannot be armed. This can happen if, for example, register_ftrace_function() finds an IPMODIFY conflict (since kprobe_ftrace_ops has this flag set) and returns an error. Such a conflict is possible since livepatches also set the IPMODIFY flag for their ftrace_ops. arm_all_kprobes() keeps its current behavior and attempts to arm all kprobes. It returns the last encountered error and gives a warning if not all probes could be armed. This patch is based on Petr Mladek's original patchset (patches 2 and 3) back in 2015, which improved kprobes error handling, found here: https://lkml.org/lkml/2015/2/26/452 However, further work on this had been paused since then and the patches were not upstreamed. Based-on-patches-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jessica Yu <jeyu@kernel.org> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David S . Miller <davem@davemloft.net> Cc: Jiri Kosina <jikos@kernel.org> Cc: Joe Lawrence <joe.lawrence@redhat.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Miroslav Benes <mbenes@suse.cz> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: live-patching@vger.kernel.org Link: http://lkml.kernel.org/r/20180109235124.30886-2-jeyu@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-20kprobes: Disable the jprobes APIsMasami Hiramatsu
Disable the jprobes APIs and comment out the jprobes API function code. This is in preparation of removing all jprobes related code (including kprobe's break_handler). Nowadays ftrace and other tracing features are mature enough to replace jprobes use-cases. Users can safely use ftrace and perf probe etc. for their use cases. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David S . Miller <davem@davemloft.net> Cc: Ian McDonald <ian.mcdonald@jandi.co.nz> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlad Yasevich <vyasevich@gmail.com> Link: http://lkml.kernel.org/r/150724527741.5014.15465541485637899227.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-20kprobes: Use synchronize_rcu_tasks() for optprobe with CONFIG_PREEMPT=yMasami Hiramatsu
We want to wait for all potentially preempted kprobes trampoline execution to have completed. This guarantees that any freed trampoline memory is not in use by any task in the system anymore. synchronize_rcu_tasks() gives such a guarantee, so use it. Also, this guarantees to wait for all potentially preempted tasks on the instructions which will be replaced with a jump. Since this becomes a problem only when CONFIG_PREEMPT=y, enable CONFIG_TASKS_RCU=y for synchronize_rcu_tasks() in that case. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Naveen N . Rao <naveen.n.rao@linux.vnet.ibm.com> Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/150845661962.5443.17724352636247312231.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-18Revert "kprobes: Warn if optprobe handler tries to change execution path"Naveen N. Rao
This reverts commit: e863d539614641 ("kprobes: Warn if optprobe handler tries to change execution path") On PowerPC, we place a probe at kretprobe_trampoline to catch function returns and with CONFIG_OPTPROBES=y, this probe gets optimized. This works for us due to the way we handle the optprobe as described in commit: 762df10bad6954 ("powerpc/kprobes: Optimize kprobe in kretprobe_trampoline()") With the above commit, we end up with a warning. As such, revert this change. Reported-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20171017081834.3629-1-naveen.n.rao@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-28kprobes: Warn if optprobe handler tries to change execution pathMasami Hiramatsu
Warn if optprobe handler tries to change execution path. As described in Documentation/kprobes.txt, with optprobe user handler can not change instruction pointer. In that case user must avoid optimizing the kprobes by setting post_handler or break_handler. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Alexei Starovoitov <ast@fb.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/150581521955.32348.3615624715034787365.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-28kprobes/x86: Make insn buffer always ROX and use text_poke()Masami Hiramatsu
Make insn buffer always ROX and use text_poke() to write the copied instructions instead of set_memory_*(). This makes instruction buffer stronger against other kernel subsystems because there is no window time to modify the buffer. Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@in.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: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/150304463032.17009.14195368040691676813.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-07-08kprobes: Ensure that jprobe probepoints are at function entryNaveen N. Rao
Similar to commit 90ec5e89e393c ("kretprobes: Ensure probe location is at function entry"), ensure that the jprobe probepoint is at function entry. Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/a4525af6c5a42df385efa31251246cf7cca73598.1499443367.git.naveen.n.rao@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-07-08kprobes: Simplify register_jprobes()Naveen N. Rao
Re-factor jprobe registration functions as the current version is getting too unwieldy. Move the actual jprobe registration to register_jprobe() and re-organize code accordingly. Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/089cae4bfe73767f765291ee0e6fb0c3d240e5f1.1499443367.git.naveen.n.rao@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-07-08kprobes: Rename [arch_]function_offset_within_entry() to ↵Naveen N. Rao
[arch_]kprobe_on_func_entry() Rename function_offset_within_entry() to scope it to kprobe namespace by using kprobe_ prefix, and to also simplify it. Suggested-by: Ingo Molnar <mingo@kernel.org> Suggested-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> 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/3aa6c7e2e4fb6e00f3c24fa306496a66edb558ea.1499443367.git.naveen.n.rao@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-07-03Merge branch 'smp-hotplug-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull SMP hotplug updates from Thomas Gleixner: "This update is primarily a cleanup of the CPU hotplug locking code. The hotplug locking mechanism is an open coded RWSEM, which allows recursive locking. The main problem with that is the recursive nature as it evades the full lockdep coverage and hides potential deadlocks. The rework replaces the open coded RWSEM with a percpu RWSEM and establishes full lockdep coverage that way. The bulk of the changes fix up recursive locking issues and address the now fully reported potential deadlocks all over the place. Some of these deadlocks have been observed in the RT tree, but on mainline the probability was low enough to hide them away." * 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (37 commits) cpu/hotplug: Constify attribute_group structures powerpc: Only obtain cpu_hotplug_lock if called by rtasd ARM/hw_breakpoint: Fix possible recursive locking for arch_hw_breakpoint_init cpu/hotplug: Remove unused check_for_tasks() function perf/core: Don't release cred_guard_mutex if not taken cpuhotplug: Link lock stacks for hotplug callbacks acpi/processor: Prevent cpu hotplug deadlock sched: Provide is_percpu_thread() helper cpu/hotplug: Convert hotplug locking to percpu rwsem s390: Prevent hotplug rwsem recursion arm: Prevent hotplug rwsem recursion arm64: Prevent cpu hotplug rwsem recursion kprobes: Cure hotplug lock ordering issues jump_label: Reorder hotplug lock and jump_label_lock perf/tracing/cpuhotplug: Fix locking order ACPI/processor: Use cpu_hotplug_disable() instead of get_online_cpus() PCI: Replace the racy recursion prevention PCI: Use cpu_hotplug_disable() instead of get_online_cpus() perf/x86/intel: Drop get_online_cpus() in intel_snb_check_microcode() x86/perf: Drop EXPORT of perf_check_microcode ...
2017-05-26kprobes/x86: Fix to set RWX bits correctly before releasing trampolineMasami Hiramatsu
Fix kprobes to set(recover) RWX bits correctly on trampoline buffer before releasing it. Releasing readonly page to module_memfree() crash the kernel. Without this fix, if kprobes user register a bunch of kprobes in function body (since kprobes on function entry usually use ftrace) and unregister it, kernel hits a BUG and crash. Link: http://lkml.kernel.org/r/149570868652.3518.14120169373590420503.stgit@devbox Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Fixes: d0381c81c2f7 ("kprobes/x86: Set kprobes pages read-only") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2017-05-26kprobes: Cure hotplug lock ordering issuesThomas Gleixner
Converting the cpu hotplug locking to a percpu rwsem unearthed hidden lock ordering problems. There is a wide range of locks involved in this: kprobe_mutex, jump_label_mutex, ftrace_lock, text_mutex, event_mutex, module_mutex, func_hash->regex_lock and a gazillion of lock order permutations with nested get_online_cpus() calls. Some of those permutations are potential deadlocks even with the current nesting hotplug locking scheme, but they can't be discovered by lockdep. The conversion of the hotplug locking to a percpu rwsem requires to prevent nested locking, so it's required to take the hotplug rwsem early in the call chain and establish a proper lock order. After quite some analysis and going down the wrong road severa times the following lock order has been chosen: kprobe_mutex -> cpus_rwsem -> jump_label_mutex -> text_mutex For kprobes which hook on an ftrace function trace point, it's required to drop cpus_rwsem before calling into the ftrace code to avoid a deadlock on the func_hash->regex_lock. [ Steven: Ftrace interaction fixes ] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@kernel.org> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Link: http://lkml.kernel.org/r/20170524081549.104864779@linutronix.de
2017-05-17kprobes: Document how optimized kprobes are removed from module unloadSteven Rostedt (VMware)
Thomas discovered a bug where the kprobe trace tests had a race condition where the kprobe_optimizer called from a delayed work queue that does the optimizing and "unoptimizing" of a kprobe, can try to modify the text after it has been freed by the init code. The kprobe trace selftest is a special case, and Thomas and myself investigated to see if there's a chance that this could also be a bug with module unloading, as the code is not obvious to how it handles this. After adding lots of printks, I figured it out. Thomas suggested that this should be commented so that others will not have to go through this exercise again. Link: http://lkml.kernel.org/r/20170516145835.3827d3aa@gandalf.local.home Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2017-05-17tracing/kprobes: Enforce kprobes teardown after testingThomas Gleixner
Enabling the tracer selftest triggers occasionally the warning in text_poke(), which warns when the to be modified page is not marked reserved. The reason is that the tracer selftest installs kprobes on functions marked __init for testing. These probes are removed after the tests, but that removal schedules the delayed kprobes_optimizer work, which will do the actual text poke. If the work is executed after the init text is freed, then the warning triggers. The bug can be reproduced reliably when the work delay is increased. Flush the optimizer work and wait for the optimizing/unoptimizing lists to become empty before returning from the kprobes tracer selftest. That ensures that all operations which were queued due to the probes removal have completed. Link: http://lkml.kernel.org/r/20170516094802.76a468bb@gandalf.local.home Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: stable@vger.kernel.org Fixes: 6274de498 ("kprobes: Support delayed unoptimizing") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2017-05-05Merge tag 'powerpc-4.12-1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux Pull powerpc updates from Michael Ellerman: "Highlights include: - Larger virtual address space on 64-bit server CPUs. By default we use a 128TB virtual address space, but a process can request access to the full 512TB by passing a hint to mmap(). - Support for the new Power9 "XIVE" interrupt controller. - TLB flushing optimisations for the radix MMU on Power9. - Support for CAPI cards on Power9, using the "Coherent Accelerator Interface Architecture 2.0". - The ability to configure the mmap randomisation limits at build and runtime. - Several small fixes and cleanups to the kprobes code, as well as support for KPROBES_ON_FTRACE. - Major improvements to handling of system reset interrupts, correctly treating them as NMIs, giving them a dedicated stack and using a new hypervisor call to trigger them, all of which should aid debugging and robustness. - Many fixes and other minor enhancements. Thanks to: Alastair D'Silva, Alexey Kardashevskiy, Alistair Popple, Andrew Donnellan, Aneesh Kumar K.V, Anshuman Khandual, Anton Blanchard, Balbir Singh, Ben Hutchings, Benjamin Herrenschmidt, Bhupesh Sharma, Chris Packham, Christian Zigotzky, Christophe Leroy, Christophe Lombard, Daniel Axtens, David Gibson, Gautham R. Shenoy, Gavin Shan, Geert Uytterhoeven, Guilherme G. Piccoli, Hamish Martin, Hari Bathini, Kees Cook, Laurent Dufour, Madhavan Srinivasan, Mahesh J Salgaonkar, Mahesh Salgaonkar, Masami Hiramatsu, Matt Brown, Matthew R. Ochs, Michael Neuling, Naveen N. Rao, Nicholas Piggin, Oliver O'Halloran, Pan Xinhui, Paul Mackerras, Rashmica Gupta, Russell Currey, Sukadev Bhattiprolu, Thadeu Lima de Souza Cascardo, Tobin C. Harding, Tyrel Datwyler, Uma Krishnan, Vaibhav Jain, Vipin K Parashar, Yang Shi" * tag 'powerpc-4.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (214 commits) powerpc/64s: Power9 has no LPCR[VRMASD] field so don't set it powerpc/powernv: Fix TCE kill on NVLink2 powerpc/mm/radix: Drop support for CPUs without lockless tlbie powerpc/book3s/mce: Move add_taint() later in virtual mode powerpc/sysfs: Move #ifdef CONFIG_HOTPLUG_CPU out of the function body powerpc/smp: Document irq enable/disable after migrating IRQs powerpc/mpc52xx: Don't select user-visible RTAS_PROC powerpc/powernv: Document cxl dependency on special case in pnv_eeh_reset() powerpc/eeh: Clean up and document event handling functions powerpc/eeh: Avoid use after free in eeh_handle_special_event() cxl: Mask slice error interrupts after first occurrence cxl: Route eeh events to all drivers in cxl_pci_error_detected() cxl: Force context lock during EEH flow powerpc/64: Allow CONFIG_RELOCATABLE if COMPILE_TEST powerpc/xmon: Teach xmon oops about radix vectors powerpc/mm/hash: Fix off-by-one in comment about kernel contexts ids powerpc/pseries: Enable VFIO powerpc/powernv: Fix iommu table size calculation hook for small tables powerpc/powernv: Check kzalloc() return value in pnv_pci_table_alloc powerpc: Add arch/powerpc/tools directory ...
2017-04-20powerpc/kprobes: Fix handling of function offsets on ABIv2Naveen N. Rao
commit 239aeba76409 ("perf powerpc: Fix kprobe and kretprobe handling with kallsyms on ppc64le") changed how we use the offset field in struct kprobe on ABIv2. perf now offsets from the global entry point if an offset is specified and otherwise chooses the local entry point. Fix the same in kernel for kprobe API users. We do this by extending kprobe_lookup_name() to accept an additional parameter to indicate the offset specified with the kprobe registration. If offset is 0, we return the local function entry and return the global entry point otherwise. With: # cd /sys/kernel/debug/tracing/ # echo "p _do_fork" >> kprobe_events # echo "p _do_fork+0x10" >> kprobe_events before this patch: # cat ../kprobes/list c0000000000d0748 k _do_fork+0x8 [DISABLED] c0000000000d0758 k _do_fork+0x18 [DISABLED] c0000000000412b0 k kretprobe_trampoline+0x0 [OPTIMIZED] and after: # cat ../kprobes/list c0000000000d04c8 k _do_fork+0x8 [DISABLED] c0000000000d04d0 k _do_fork+0x10 [DISABLED] c0000000000412b0 k kretprobe_trampoline+0x0 [OPTIMIZED] Acked-by: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-04-20kprobes: Convert kprobe_lookup_name() to a functionNaveen N. Rao
The macro is now pretty long and ugly on powerpc. In the light of further changes needed here, convert it to a __weak variant to be over-ridden with a nicer looking function. Suggested-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-04-20kprobes: Skip preparing optprobe if the probe is ftrace-basedMasami Hiramatsu
Skip preparing optprobe if the probe is ftrace-based, since anyway, it must not be optimized (or already optimized by ftrace). Tested-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-03-15trace/kprobes: Fix check for kretprobe offset within function entryNaveen N. Rao
perf specifies an offset from _text and since this offset is fed directly into the arch-specific helper, kprobes tracer rejects installation of kretprobes through perf. Fix this by looking up the actual offset from a function for the specified sym+offset. Refactor and reuse existing routines to limit code duplication -- we repurpose kprobe_addr() for determining final kprobe address and we split out the function entry offset determination into a separate generic helper. Before patch: naveen@ubuntu:~/linux/tools/perf$ sudo ./perf probe -v do_open%return probe-definition(0): do_open%return symbol:do_open file:(null) line:0 offset:0 return:1 lazy:(null) 0 arguments Looking at the vmlinux_path (8 entries long) Using /boot/vmlinux for symbols Open Debuginfo file: /boot/vmlinux Try to find probe point from debuginfo. Matched function: do_open [2d0c7ff] Probe point found: do_open+0 Matched function: do_open [35d76dc] found inline addr: 0xc0000000004ba9c4 Failed to find "do_open%return", because do_open is an inlined function and has no return point. An error occurred in debuginfo analysis (-22). Trying to use symbols. Opening /sys/kernel/debug/tracing//README write=0 Opening /sys/kernel/debug/tracing//kprobe_events write=1 Writing event: r:probe/do_open _text+4469776 Failed to write event: Invalid argument Error: Failed to add events. Reason: Invalid argument (Code: -22) naveen@ubuntu:~/linux/tools/perf$ dmesg | tail <snip> [ 33.568656] Given offset is not valid for return probe. After patch: naveen@ubuntu:~/linux/tools/perf$ sudo ./perf probe -v do_open%return probe-definition(0): do_open%return symbol:do_open file:(null) line:0 offset:0 return:1 lazy:(null) 0 arguments Looking at the vmlinux_path (8 entries long) Using /boot/vmlinux for symbols Open Debuginfo file: /boot/vmlinux Try to find probe point from debuginfo. Matched function: do_open [2d0c7d6] Probe point found: do_open+0 Matched function: do_open [35d76b3] found inline addr: 0xc0000000004ba9e4 Failed to find "do_open%return", because do_open is an inlined function and has no return point. An error occurred in debuginfo analysis (-22). Trying to use symbols. Opening /sys/kernel/debug/tracing//README write=0 Opening /sys/kernel/debug/tracing//kprobe_events write=1 Writing event: r:probe/do_open _text+4469808 Writing event: r:probe/do_open_1 _text+4956344 Added new events: probe:do_open (on do_open%return) probe:do_open_1 (on do_open%return) You can now use it in all perf tools, such as: perf record -e probe:do_open_1 -aR sleep 1 naveen@ubuntu:~/linux/tools/perf$ sudo cat /sys/kernel/debug/kprobes/list c000000000041370 k kretprobe_trampoline+0x0 [OPTIMIZED] c0000000004ba0b8 r do_open+0x8 [DISABLED] c000000000443430 r do_open+0x0 [DISABLED] Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/d8cd1ef420ec22e3643ac332fdabcffc77319a42.1488961018.git.naveen.n.rao@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2017-03-14kprobes: Convert kprobe_exceptions_notify to use NOKPROBE_SYMBOLNaveen N. Rao
commit fc62d0207ae0 ("kprobes: Introduce weak variant of kprobe_exceptions_notify()") used the __kprobes annotation to exclude kprobe_exceptions_notify from being probed. Since NOKPROBE_SYMBOL() is a better way to do this enabling the symbol to be discovered as being blacklisted, change over to using NOKPROBE_SYMBOL(). Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/3f25bf400da5c222cd9b10eec6ded2d6b58209f8.1488991670.git.naveen.n.rao@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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