summaryrefslogtreecommitdiff
path: root/kernel/trace
AgeCommit message (Collapse)Author
2018-12-21tracing: Fix memory leak of instance function hash filtersSteven Rostedt (VMware)
commit 2840f84f74035e5a535959d5f17269c69fa6edc5 upstream. The following commands will cause a memory leak: # cd /sys/kernel/tracing # mkdir instances/foo # echo schedule > instance/foo/set_ftrace_filter # rmdir instances/foo The reason is that the hashes that hold the filters to set_ftrace_filter and set_ftrace_notrace are not freed if they contain any data on the instance and the instance is removed. Found by kmemleak detector. Cc: stable@vger.kernel.org Fixes: 591dffdade9f ("ftrace: Allow for function tracing instance to filter functions") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-12-21tracing: Fix memory leak in set_trigger_filter()Steven Rostedt (VMware)
commit 3cec638b3d793b7cacdec5b8072364b41caeb0e1 upstream. When create_event_filter() fails in set_trigger_filter(), the filter may still be allocated and needs to be freed. The caller expects the data->filter to be updated with the new filter, even if the new filter failed (we could add an error message by setting set_str parameter of create_event_filter(), but that's another update). But because the error would just exit, filter was left hanging and nothing could free it. Found by kmemleak detector. Cc: stable@vger.kernel.org Fixes: bac5fb97a173a ("tracing: Add and use generic set_trigger_filter() implementation") Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-11-10tracing: Fix enabling of syscall events on the command lineSteven Rostedt (Red Hat)
[ Upstream commit ce1039bd3a89e99e4f624e75fb1777fc92d76eb3 ] Commit 5f893b2639b2 "tracing: Move enabling tracepoints to just after rcu_init()" broke the enabling of system call events from the command line. The reason was that the enabling of command line trace events was moved before PID 1 started, and the syscall tracepoints require that all tasks have the TIF_SYSCALL_TRACEPOINT flag set. But the swapper task (pid 0) is not part of that. Since the swapper task is the only task that is running at this early in boot, no task gets the flag set, and the tracepoint never gets reached. Instead of setting the swapper task flag (there should be no reason to do that), re-enabled trace events again after the init thread (PID 1) has been started. It requires disabling all command line events and re-enabling them, as just enabling them again will not reset the logic to set the TIF_SYSCALL_TRACEPOINT flag, as the syscall tracepoint will be fooled into thinking that it was already set, and wont try setting it again. For this reason, we must first disable it and re-enable it. Link: http://lkml.kernel.org/r/1421188517-18312-1-git-send-email-mpe@ellerman.id.au Link: http://lkml.kernel.org/r/20150115040506.216066449@goodmis.org Reported-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2018-10-13ring-buffer: Allow for rescheduling when removing pagesVaibhav Nagarnaik
commit 83f365554e47997ec68dc4eca3f5dce525cd15c3 upstream. When reducing ring buffer size, pages are removed by scheduling a work item on each CPU for the corresponding CPU ring buffer. After the pages are removed from ring buffer linked list, the pages are free()d in a tight loop. The loop does not give up CPU until all pages are removed. In a worst case behavior, when lot of pages are to be freed, it can cause system stall. After the pages are removed from the list, the free() can happen while the work is rescheduled. Call cond_resched() in the loop to prevent the system hangup. Link: http://lkml.kernel.org/r/20180907223129.71994-1-vnagarnaik@google.com Cc: stable@vger.kernel.org Fixes: 83f40318dab00 ("ring-buffer: Make removal of ring buffer pages atomic") Reported-by: Jason Behmer <jbehmer@google.com> Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-09uprobes: Use synchronize_rcu() not synchronize_sched()Steven Rostedt (VMware)
commit 016f8ffc48cb01d1e7701649c728c5d2e737d295 upstream. While debugging another bug, I was looking at all the synchronize*() functions being used in kernel/trace, and noticed that trace_uprobes was using synchronize_sched(), with a comment to synchronize with {u,ret}_probe_trace_func(). When looking at those functions, the data is protected with "rcu_read_lock()" and not with "rcu_read_lock_sched()". This is using the wrong synchronize_*() function. Link: http://lkml.kernel.org/r/20180809160553.469e1e32@gandalf.local.home Cc: stable@vger.kernel.org Fixes: 70ed91c6ec7f8 ("tracing/uprobes: Support ftrace_event_file base multibuffer") Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-09tracing/blktrace: Fix to allow setting same valueSteven Rostedt (VMware)
commit 757d9140072054528b13bbe291583d9823cde195 upstream. Masami Hiramatsu reported: Current trace-enable attribute in sysfs returns an error if user writes the same setting value as current one, e.g. # cat /sys/block/sda/trace/enable 0 # echo 0 > /sys/block/sda/trace/enable bash: echo: write error: Invalid argument # echo 1 > /sys/block/sda/trace/enable # echo 1 > /sys/block/sda/trace/enable bash: echo: write error: Device or resource busy But this is not a preferred behavior, it should ignore if new setting is same as current one. This fixes the problem as below. # cat /sys/block/sda/trace/enable 0 # echo 0 > /sys/block/sda/trace/enable # echo 1 > /sys/block/sda/trace/enable # echo 1 > /sys/block/sda/trace/enable Link: http://lkml.kernel.org/r/20180816103802.08678002@gandalf.local.home Cc: Ingo Molnar <mingo@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: linux-block@vger.kernel.org Cc: stable@vger.kernel.org Fixes: cd649b8bb830d ("blktrace: remove sysfs_blk_trace_enable_show/store()") Reported-by: Masami Hiramatsu <mhiramat@kernel.org> Tested-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-09tracing: Do not call start/stop() functions when tracing_on does not changeSteven Rostedt (VMware)
commit f143641bfef9a4a60c57af30de26c63057e7e695 upstream. Currently, when one echo's in 1 into tracing_on, the current tracer's "start()" function is executed, even if tracing_on was already one. This can lead to strange side effects. One being that if the hwlat tracer is enabled, and someone does "echo 1 > tracing_on" into tracing_on, the hwlat tracer's start() function is called again which will recreate another kernel thread, and make it unable to remove the old one. Link: http://lkml.kernel.org/r/1533120354-22923-1-git-send-email-erica.bugden@linutronix.de Cc: stable@vger.kernel.org Fixes: 2df8f8a6a897e ("tracing: Fix regression with irqsoff tracer and tracing_on file") Reported-by: Erica Bugden <erica.bugden@linutronix.de> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-08-28tracing: Use __printf markup to silence compilerMathieu Malaterre
[ Upstream commit 26b68dd2f48fe7699a89f0cfbb9f4a650dc1c837 ] Silence warnings (triggered at W=1) by adding relevant __printf attributes. CC kernel/trace/trace.o kernel/trace/trace.c: In function ‘__trace_array_vprintk’: kernel/trace/trace.c:2979:2: warning: function might be possible candidate for ‘gnu_printf’ format attribute [-Wsuggest-attribute=format] len = vscnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args); ^~~ AR kernel/trace/built-in.o Link: http://lkml.kernel.org/r/20180308205843.27447-1-malat@debian.org Signed-off-by: Mathieu Malaterre <malat@debian.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-08-09ring_buffer: tracing: Inherit the tracing setting to next ring bufferMasami Hiramatsu
commit 73c8d8945505acdcbae137c2e00a1232e0be709f upstream. Maintain the tracing on/off setting of the ring_buffer when switching to the trace buffer snapshot. Taking a snapshot is done by swapping the backup ring buffer (max_tr_buffer). But since the tracing on/off setting is defined by the ring buffer, when swapping it, the tracing on/off setting can also be changed. This causes a strange result like below: /sys/kernel/debug/tracing # cat tracing_on 1 /sys/kernel/debug/tracing # echo 0 > tracing_on /sys/kernel/debug/tracing # cat tracing_on 0 /sys/kernel/debug/tracing # echo 1 > snapshot /sys/kernel/debug/tracing # cat tracing_on 1 /sys/kernel/debug/tracing # echo 1 > snapshot /sys/kernel/debug/tracing # cat tracing_on 0 We don't touch tracing_on, but snapshot changes tracing_on setting each time. This is an anomaly, because user doesn't know that each "ring_buffer" stores its own tracing-enable state and the snapshot is done by swapping ring buffers. Link: http://lkml.kernel.org/r/153149929558.11274.11730609978254724394.stgit@devbox Cc: Ingo Molnar <mingo@redhat.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Tom Zanussi <tom.zanussi@linux.intel.com> Cc: Hiraku Toyooka <hiraku.toyooka@cybertrust.co.jp> Cc: stable@vger.kernel.org Fixes: debdd57f5145 ("tracing: Make a snapshot feature available from userspace") Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> [ Updated commit log and comment in the code ] Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-08-09tracing: Quiet gcc warning about maybe unused link variableSteven Rostedt (VMware)
commit 2519c1bbe38d7acacc9aacba303ca6f97482ed53 upstream. Commit 57ea2a34adf4 ("tracing/kprobes: Fix trace_probe flags on enable_trace_kprobe() failure") added an if statement that depends on another if statement that gcc doesn't see will initialize the "link" variable and gives the warning: "warning: 'link' may be used uninitialized in this function" It is really a false positive, but to quiet the warning, and also to make sure that it never actually is used uninitialized, initialize the "link" variable to NULL and add an if (!WARN_ON_ONCE(!link)) where the compiler thinks it could be used uninitialized. Cc: stable@vger.kernel.org Fixes: 57ea2a34adf4 ("tracing/kprobes: Fix trace_probe flags on enable_trace_kprobe() failure") 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>
2018-08-09tracing/kprobes: Fix trace_probe flags on enable_trace_kprobe() failureArtem Savkov
commit 57ea2a34adf40f3a6e88409aafcf803b8945619a upstream. If enable_trace_kprobe fails to enable the probe in enable_k(ret)probe it returns an error, but does not unset the tp flags it set previously. This results in a probe being considered enabled and failures like being unable to remove the probe through kprobe_events file since probes_open() expects every probe to be disabled. Link: http://lkml.kernel.org/r/20180725102826.8300-1-asavkov@redhat.com Link: http://lkml.kernel.org/r/20180725142038.4765-1-asavkov@redhat.com Cc: Ingo Molnar <mingo@redhat.com> Cc: stable@vger.kernel.org Fixes: 41a7dd420c57 ("tracing/kprobes: Support ftrace_event_file base multibuffer") Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Artem Savkov <asavkov@redhat.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-08-09tracing: Fix possible double free in event_enable_trigger_func()Steven Rostedt (VMware)
commit 15cc78644d0075e76d59476a4467e7143860f660 upstream. There was a case that triggered a double free in event_trigger_callback() due to the called reg() function freeing the trigger_data and then it getting freed again by the error return by the caller. The solution there was to up the trigger_data ref count. Code inspection found that event_enable_trigger_func() has the same issue, but is not as easy to trigger (requires harder to trigger failures). It needs to be solved slightly different as it needs more to clean up when the reg() function fails. Link: http://lkml.kernel.org/r/20180725124008.7008e586@gandalf.local.home Cc: stable@vger.kernel.org Fixes: 7862ad1846e99 ("tracing: Add 'enable_event' and 'disable_event' event trigger commands") Reivewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-08-09tracing: Fix double free of event_trigger_dataSteven Rostedt (VMware)
commit 1863c387259b629e4ebfb255495f67cd06aa229b upstream. Running the following: # cd /sys/kernel/debug/tracing # echo 500000 > buffer_size_kb [ Or some other number that takes up most of memory ] # echo snapshot > events/sched/sched_switch/trigger Triggers the following bug: ------------[ cut here ]------------ kernel BUG at mm/slub.c:296! invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC PTI CPU: 6 PID: 6878 Comm: bash Not tainted 4.18.0-rc6-test+ #1066 Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01 v03.03 07/14/2016 RIP: 0010:kfree+0x16c/0x180 Code: 05 41 0f b6 72 51 5b 5d 41 5c 4c 89 d7 e9 ac b3 f8 ff 48 89 d9 48 89 da 41 b8 01 00 00 00 5b 5d 41 5c 4c 89 d6 e9 f4 f3 ff ff <0f> 0b 0f 0b 48 8b 3d d9 d8 f9 00 e9 c1 fe ff ff 0f 1f 40 00 0f 1f RSP: 0018:ffffb654436d3d88 EFLAGS: 00010246 RAX: ffff91a9d50f3d80 RBX: ffff91a9d50f3d80 RCX: ffff91a9d50f3d80 RDX: 00000000000006a4 RSI: ffff91a9de5a60e0 RDI: ffff91a9d9803500 RBP: ffffffff8d267c80 R08: 00000000000260e0 R09: ffffffff8c1a56be R10: fffff0d404543cc0 R11: 0000000000000389 R12: ffffffff8c1a56be R13: ffff91a9d9930e18 R14: ffff91a98c0c2890 R15: ffffffff8d267d00 FS: 00007f363ea64700(0000) GS:ffff91a9de580000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055c1cacc8e10 CR3: 00000000d9b46003 CR4: 00000000001606e0 Call Trace: event_trigger_callback+0xee/0x1d0 event_trigger_write+0xfc/0x1a0 __vfs_write+0x33/0x190 ? handle_mm_fault+0x115/0x230 ? _cond_resched+0x16/0x40 vfs_write+0xb0/0x190 ksys_write+0x52/0xc0 do_syscall_64+0x5a/0x160 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f363e16ab50 Code: 73 01 c3 48 8b 0d 38 83 2c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d 79 db 2c 00 00 75 10 b8 01 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 1e e3 01 00 48 89 04 24 RSP: 002b:00007fff9a4c6378 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000009 RCX: 00007f363e16ab50 RDX: 0000000000000009 RSI: 000055c1cacc8e10 RDI: 0000000000000001 RBP: 000055c1cacc8e10 R08: 00007f363e435740 R09: 00007f363ea64700 R10: 0000000000000073 R11: 0000000000000246 R12: 0000000000000009 R13: 0000000000000001 R14: 00007f363e4345e0 R15: 00007f363e4303c0 Modules linked in: ip6table_filter ip6_tables snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic snd_hda_intel snd_hda_codec snd_hwdep snd_hda_core snd_seq snd_seq_device i915 snd_pcm snd_timer i2c_i801 snd soundcore i2c_algo_bit drm_kms_helper 86_pkg_temp_thermal video kvm_intel kvm irqbypass wmi e1000e ---[ end trace d301afa879ddfa25 ]--- The cause is because the register_snapshot_trigger() call failed to allocate the snapshot buffer, and then called unregister_trigger() which freed the data that was passed to it. Then on return to the function that called register_snapshot_trigger(), as it sees it failed to register, it frees the trigger_data again and causes a double free. By calling event_trigger_init() on the trigger_data (which only ups the reference counter for it), and then event_trigger_free() afterward, the trigger_data would not get freed by the registering trigger function as it would only up and lower the ref count for it. If the register trigger function fails, then the event_trigger_free() called after it will free the trigger data normally. Link: http://lkml.kernel.org/r/20180724191331.738eb819@gandalf.local.home Cc: stable@vger.kerne.org Fixes: 93e31ffbf417 ("tracing: Add 'snapshot' event trigger command") Reported-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-06-13tracing: Fix crash when freeing instances with event triggersSteven Rostedt (VMware)
commit 86b389ff22bd6ad8fd3cb98e41cd271886c6d023 upstream. If a instance has an event trigger enabled when it is freed, it could cause an access of free memory. Here's the case that crashes: # cd /sys/kernel/tracing # mkdir instances/foo # echo snapshot > instances/foo/events/initcall/initcall_start/trigger # rmdir instances/foo Would produce: general protection fault: 0000 [#1] PREEMPT SMP PTI Modules linked in: tun bridge ... CPU: 5 PID: 6203 Comm: rmdir Tainted: G W 4.17.0-rc4-test+ #933 Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01 v03.03 07/14/2016 RIP: 0010:clear_event_triggers+0x3b/0x70 RSP: 0018:ffffc90003783de0 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 6b6b6b6b6b6b6b2b RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8800c7130ba0 RBP: ffffc90003783e00 R08: ffff8801131993f8 R09: 0000000100230016 R10: ffffc90003783d80 R11: 0000000000000000 R12: ffff8800c7130ba0 R13: ffff8800c7130bd8 R14: ffff8800cc093768 R15: 00000000ffffff9c FS: 00007f6f4aa86700(0000) GS:ffff88011eb40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6f4a5aed60 CR3: 00000000cd552001 CR4: 00000000001606e0 Call Trace: event_trace_del_tracer+0x2a/0xc5 instance_rmdir+0x15c/0x200 tracefs_syscall_rmdir+0x52/0x90 vfs_rmdir+0xdb/0x160 do_rmdir+0x16d/0x1c0 __x64_sys_rmdir+0x17/0x20 do_syscall_64+0x55/0x1a0 entry_SYSCALL_64_after_hwframe+0x49/0xbe This was due to the call the clears out the triggers when an instance is being deleted not removing the trigger from the link list. Cc: stable@vger.kernel.org Fixes: 85f2b08268c01 ("tracing: Add basic event trigger framework") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-16tracing/uprobe_event: Fix strncpy corner caseMasami Hiramatsu
commit 50268a3d266ecfdd6c5873d62b2758d9732fc598 upstream. Fix string fetch function to terminate with NUL. It is OK to drop the rest of string. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Song Liu <songliubraving@fb.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: security@kernel.org Cc: 范龙飞 <long7573@126.com> Fixes: 5baaa59ef09e ("tracing/probes: Implement 'memory' fetch method for uprobes") Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-16tracing: Fix regex_match_front() to not over compare the test stringSteven Rostedt (VMware)
commit dc432c3d7f9bceb3de6f5b44fb9c657c9810ed6d upstream. The regex match function regex_match_front() in the tracing filter logic, was fixed to test just the pattern length from testing the entire test string. That is, it went from strncmp(str, r->pattern, len) to strcmp(str, r->pattern, r->len). The issue is that str is not guaranteed to be nul terminated, and if r->len is greater than the length of str, it can access more memory than is allocated. The solution is to add a simple test if (len < r->len) return 0. Cc: stable@vger.kernel.org Fixes: 285caad415f45 ("tracing/filters: Fix MATCH_FRONT_ONLY filter matching") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-08tracing: probeevent: Fix to support minus offset from symbolMasami Hiramatsu
commit c5d343b6b7badd1f5fe0873eff2e8d63a193e732 upstream. In Documentation/trace/kprobetrace.txt, it says @SYM[+|-offs] : Fetch memory at SYM +|- offs (SYM should be a data symbol) However, the parser doesn't parse minus offset correctly, since commit 2fba0c8867af ("tracing/kprobes: Fix probe offset to be unsigned") drops minus ("-") offset support for kprobe probe address usage. This fixes the traceprobe_split_symbol_offset() to parse minus offset again with checking the offset range, and add a minus offset check in kprobe probe address usage. Link: http://lkml.kernel.org/r/152129028983.31874.13419301530285775521.stgit@devbox Cc: Ingo Molnar <mingo@redhat.com> Cc: Tom Zanussi <tom.zanussi@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com> Cc: stable@vger.kernel.org Fixes: 2fba0c8867af ("tracing/kprobes: Fix probe offset to be unsigned") Acked-by: Namhyung Kim <namhyung@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>
2018-01-02ring-buffer: Mask out the info bits when returning buffer page lengthSteven Rostedt (VMware)
commit 45d8b80c2ac5d21cd1e2954431fb676bc2b1e099 upstream. Two info bits were added to the "commit" part of the ring buffer data page when returned to be consumed. This was to inform the user space readers that events have been missed, and that the count may be stored at the end of the page. What wasn't handled, was the splice code that actually called a function to return the length of the data in order to zero out the rest of the page before sending it up to user space. These data bits were returned with the length making the value negative, and that negative value was not checked. It was compared to PAGE_SIZE, and only used if the size was less than PAGE_SIZE. Luckily PAGE_SIZE is unsigned long which made the compare an unsigned compare, meaning the negative size value did not end up causing a large portion of memory to be randomly zeroed out. Fixes: 66a8cb95ed040 ("ring-buffer: Add place holder recording of dropped events") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-02tracing: Fix crash when it fails to alloc ring bufferJing Xia
commit 24f2aaf952ee0b59f31c3a18b8b36c9e3d3c2cf5 upstream. Double free of the ring buffer happens when it fails to alloc new ring buffer instance for max_buffer if TRACER_MAX_TRACE is configured. The root cause is that the pointer is not set to NULL after the buffer is freed in allocate_trace_buffers(), and the freeing of the ring buffer is invoked again later if the pointer is not equal to Null, as: instance_mkdir() |-allocate_trace_buffers() |-allocate_trace_buffer(tr, &tr->trace_buffer...) |-allocate_trace_buffer(tr, &tr->max_buffer...) // allocate fail(-ENOMEM),first free // and the buffer pointer is not set to null |-ring_buffer_free(tr->trace_buffer.buffer) // out_free_tr |-free_trace_buffers() |-free_trace_buffer(&tr->trace_buffer); //if trace_buffer is not null, free again |-ring_buffer_free(buf->buffer) |-rb_free_cpu_buffer(buffer->buffers[cpu]) // ring_buffer_per_cpu is null, and // crash in ring_buffer_per_cpu->pages Link: http://lkml.kernel.org/r/20171226071253.8968-1-chunyan.zhang@spreadtrum.com Fixes: 737223fbca3b1 ("tracing: Consolidate buffer allocation code") Signed-off-by: Jing Xia <jing.xia@spreadtrum.com> Signed-off-by: Chunyan Zhang <chunyan.zhang@spreadtrum.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-02tracing: Fix possible double free on failure of allocating trace bufferSteven Rostedt (VMware)
commit 4397f04575c44e1440ec2e49b6302785c95fd2f8 upstream. Jing Xia and Chunyan Zhang reported that on failing to allocate part of the tracing buffer, memory is freed, but the pointers that point to them are not initialized back to NULL, and later paths may try to free the freed memory again. Jing and Chunyan fixed one of the locations that does this, but missed a spot. Link: http://lkml.kernel.org/r/20171226071253.8968-1-chunyan.zhang@spreadtrum.com Fixes: 737223fbca3b1 ("tracing: Consolidate buffer allocation code") Reported-by: Jing Xia <jing.xia@spreadtrum.com> Reported-by: Chunyan Zhang <chunyan.zhang@spreadtrum.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-02tracing: Remove extra zeroing out of the ring buffer pageSteven Rostedt (VMware)
commit 6b7e633fe9c24682df550e5311f47fb524701586 upstream. The ring_buffer_read_page() takes care of zeroing out any extra data in the page that it returns. There's no need to zero it out again from the consumer. It was removed from one consumer of this function, but read_buffers_splice_read() did not remove it, and worse, it contained a nasty bug because of it. Fixes: 2711ca237a084 ("ring-buffer: Move zeroing out excess in page to ring buffer code") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-10-05tracing: Erase irqsoff trace with empty writeBo Yan
commit 8dd33bcb7050dd6f8c1432732f930932c9d3a33e upstream. One convenient way to erase trace is "echo > trace". However, this is currently broken if the current tracer is irqsoff tracer. This is because irqsoff tracer use max_buffer as the default trace buffer. Set the max_buffer as the one to be cleared when it's the trace buffer currently in use. Link: http://lkml.kernel.org/r/1505754215-29411-1-git-send-email-byan@nvidia.com Cc: <mingo@redhat.com> Fixes: 4acd4d00f ("tracing: give easy way to clear trace buffer") Signed-off-by: Bo Yan <byan@nvidia.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-10-05tracing: Fix trace_pipe behavior for instance tracesTahsin Erdogan
commit 75df6e688ccd517e339a7c422ef7ad73045b18a2 upstream. When reading data from trace_pipe, tracing_wait_pipe() performs a check to see if tracing has been turned off after some data was read. Currently, this check always looks at global trace state, but it should be checking the trace instance where trace_pipe is located at. Because of this bug, cat instances/i1/trace_pipe in the following script will immediately exit instead of waiting for data: cd /sys/kernel/debug/tracing echo 0 > tracing_on mkdir -p instances/i1 echo 1 > instances/i1/tracing_on echo 1 > instances/i1/events/sched/sched_process_exec/enable cat instances/i1/trace_pipe Link: http://lkml.kernel.org/r/20170917102348.1615-1-tahsin@google.com Fixes: 10246fa35d4f ("tracing: give easy way to clear trace buffer") Signed-off-by: Tahsin Erdogan <tahsin@google.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-09-27tracing: Apply trace_clock changes to instance max bufferBaohong Liu
commit 170b3b1050e28d1ba0700e262f0899ffa4fccc52 upstream. Currently trace_clock timestamps are applied to both regular and max buffers only for global trace. For instance trace, trace_clock timestamps are applied only to regular buffer. But, regular and max buffers can be swapped, for example, following a snapshot. So, for instance trace, bad timestamps can be seen following a snapshot. Let's apply trace_clock timestamps to instance max buffer as well. Link: http://lkml.kernel.org/r/ebdb168d0be042dcdf51f81e696b17fabe3609c1.1504642143.git.tom.zanussi@linux.intel.com Fixes: 277ba0446 ("tracing: Add interface to allow multiple trace buffers") Signed-off-by: Baohong Liu <baohong.liu@intel.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-09-27ftrace: Fix selftest goto location on errorSteven Rostedt (VMware)
commit 46320a6acc4fb58f04bcf78c4c942cc43b20f986 upstream. In the second iteration of trace_selftest_ops(), the error goto label is wrong in the case where trace_selftest_test_global_cnt is off. In the case of error, it leaks the dynamic ops that was allocated. Fixes: 95950c2e ("ftrace: Add self-tests for multiple function trace users") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-08-30tracing: Fix freeing of filter in create_filter() when set_str is falseSteven Rostedt (VMware)
commit 8b0db1a5bdfcee0dbfa89607672598ae203c9045 upstream. Performing the following task with kmemleak enabled: # cd /sys/kernel/tracing/events/irq/irq_handler_entry/ # echo 'enable_event:kmem:kmalloc:3 if irq >' > trigger # echo 'enable_event:kmem:kmalloc:3 if irq > 31' > trigger # echo scan > /sys/kernel/debug/kmemleak # cat /sys/kernel/debug/kmemleak unreferenced object 0xffff8800b9290308 (size 32): comm "bash", pid 1114, jiffies 4294848451 (age 141.139s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffff81cef5aa>] kmemleak_alloc+0x4a/0xa0 [<ffffffff81357938>] kmem_cache_alloc_trace+0x158/0x290 [<ffffffff81261c09>] create_filter_start.constprop.28+0x99/0x940 [<ffffffff812639c9>] create_filter+0xa9/0x160 [<ffffffff81263bdc>] create_event_filter+0xc/0x10 [<ffffffff812655e5>] set_trigger_filter+0xe5/0x210 [<ffffffff812660c4>] event_enable_trigger_func+0x324/0x490 [<ffffffff812652e2>] event_trigger_write+0x1a2/0x260 [<ffffffff8138cf87>] __vfs_write+0xd7/0x380 [<ffffffff8138f421>] vfs_write+0x101/0x260 [<ffffffff8139187b>] SyS_write+0xab/0x130 [<ffffffff81cfd501>] entry_SYSCALL_64_fastpath+0x1f/0xbe [<ffffffffffffffff>] 0xffffffffffffffff The function create_filter() is passed a 'filterp' pointer that gets allocated, and if "set_str" is true, it is up to the caller to free it, even on error. The problem is that the pointer is not freed by create_filter() when set_str is false. This is a bug, and it is not up to the caller to free the filter on error if it doesn't care about the string. Link: http://lkml.kernel.org/r/1502705898-27571-2-git-send-email-chuhu@redhat.com Fixes: 38b78eb85 ("tracing: Factorize filter creation") Reported-by: Chunyu Hu <chuhu@redhat.com> Tested-by: Chunyu Hu <chuhu@redhat.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-07-27tracing: Fix kmemleak in instance_rmdirChunyu Hu
commit db9108e054700c96322b0f0028546aa4e643cf0b upstream. Hit the kmemleak when executing instance_rmdir, it forgot releasing mem of tracing_cpumask. With this fix, the warn does not appear any more. unreferenced object 0xffff93a8dfaa7c18 (size 8): comm "mkdir", pid 1436, jiffies 4294763622 (age 9134.308s) hex dump (first 8 bytes): ff ff ff ff ff ff ff ff ........ backtrace: [<ffffffff88b6567a>] kmemleak_alloc+0x4a/0xa0 [<ffffffff8861ea41>] __kmalloc_node+0xf1/0x280 [<ffffffff88b505d3>] alloc_cpumask_var_node+0x23/0x30 [<ffffffff88b5060e>] alloc_cpumask_var+0xe/0x10 [<ffffffff88571ab0>] instance_mkdir+0x90/0x240 [<ffffffff886e5100>] tracefs_syscall_mkdir+0x40/0x70 [<ffffffff886565c9>] vfs_mkdir+0x109/0x1b0 [<ffffffff8865b1d0>] SyS_mkdir+0xd0/0x100 [<ffffffff88403857>] do_syscall_64+0x67/0x150 [<ffffffff88b710e7>] return_from_SYSCALL_64+0x0/0x6a [<ffffffffffffffff>] 0xffffffffffffffff Link: http://lkml.kernel.org/r/1500546969-12594-1-git-send-email-chuhu@redhat.com Fixes: ccfe9e42e451 ("tracing: Make tracing_cpumask available for all instances") Signed-off-by: Chunyu Hu <chuhu@redhat.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-07-21tracing: Use SOFTIRQ_OFFSET for softirq dectection for more accurate resultsPavankumar Kondeti
commit c59f29cb144a6a0dfac16ede9dc8eafc02dc56ca upstream. The 's' flag is supposed to indicate that a softirq is running. This can be detected by testing the preempt_count with SOFTIRQ_OFFSET. The current code tests the preempt_count with SOFTIRQ_MASK, which would be true even when softirqs are disabled but not serving a softirq. Link: http://lkml.kernel.org/r/1481300417-3564-1-git-send-email-pkondeti@codeaurora.org Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Amit Pundir <amit.pundir@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-07-15tracing/kprobes: Allow to create probe with a module name starting with a digitSabrina Dubroca
commit 9e52b32567126fe146f198971364f68d3bc5233f upstream. Always try to parse an address, since kstrtoul() will safely fail when given a symbol as input. If that fails (which will be the case for a symbol), try to parse a symbol instead. This allows creating a probe such as: p:probe/vlan_gro_receive 8021q:vlan_gro_receive+0 Which is necessary for this command to work: perf probe -m 8021q -a vlan_gro_receive Link: http://lkml.kernel.org/r/fd72d666f45b114e2c5b9cf7e27b91de1ec966f1.1498122881.git.sd@queasysnail.net Fixes: 413d37d1e ("tracing: Add kprobe-based event tracer") Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Sabrina Dubroca <sd@queasysnail.net> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-05-25tracing/kprobes: Enforce kprobes teardown after testingThomas Gleixner
commit 30e7d894c1478c88d50ce94ddcdbd7f9763d9cdd upstream. 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> Fixes: 6274de498 ("kprobes: Support delayed unoptimizing") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-30perf: Avoid horrible stack usagePeter Zijlstra (Intel)
commit 86038c5ea81b519a8a1fcfcd5e4599aab0cdd119 upstream. Both Linus (most recent) and Steve (a while ago) reported that perf related callbacks have massive stack bloat. The problem is that software events need a pt_regs in order to properly report the event location and unwind stack. And because we could not assume one was present we allocated one on stack and filled it with minimal bits required for operation. Now, pt_regs is quite large, so this is undesirable. Furthermore it turns out that most sites actually have a pt_regs pointer available, making this even more onerous, as the stack space is pointless waste. This patch addresses the problem by observing that software events have well defined nesting semantics, therefore we can use static per-cpu storage instead of on-stack. Linus made the further observation that all but the scheduler callers of perf_sw_event() have a pt_regs available, so we change the regular perf_sw_event() to require a valid pt_regs (where it used to be optional) and add perf_sw_event_sched() for the scheduler. We have a scheduler specific call instead of a more generic _noregs() like construct because we can assume non-recursion from the scheduler and thereby simplify the code further (_noregs would have to put the recursion context call inline in order to assertain which __perf_regs element to use). One last note on the implementation of perf_trace_buf_prepare(); we allow .regs = NULL for those cases where we already have a pt_regs pointer available and do not need another. Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Reported-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Javi Merino <javi.merino@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Petr Mladek <pmladek@suse.cz> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tom Zanussi <tom.zanussi@linux.intel.com> Cc: Vaibhav Nagarnaik <vnagarnaik@google.com> Link: http://lkml.kernel.org/r/20141216115041.GW3337@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-30ring-buffer: Have ring_buffer_iter_empty() return true when emptySteven Rostedt (VMware)
commit 78f7a45dac2a2d2002f98a3a95f7979867868d73 upstream. I noticed that reading the snapshot file when it is empty no longer gives a status. It suppose to show the status of the snapshot buffer as well as how to allocate and use it. For example: ># cat snapshot # tracer: nop # # # * Snapshot is allocated * # # Snapshot commands: # echo 0 > snapshot : Clears and frees snapshot buffer # echo 1 > snapshot : Allocates snapshot buffer, if not already allocated. # Takes a snapshot of the main buffer. # echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free) # (Doesn't have to be '2' works with any number that # is not a '0' or '1') But instead it just showed an empty buffer: ># cat snapshot # tracer: nop # # entries-in-buffer/entries-written: 0/0 #P:4 # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / delay # TASK-PID CPU# |||| TIMESTAMP FUNCTION # | | | |||| | | What happened was that it was using the ring_buffer_iter_empty() function to see if it was empty, and if it was, it showed the status. But that function was returning false when it was empty. The reason was that the iter header page was on the reader page, and the reader page was empty, but so was the buffer itself. The check only tested to see if the iter was on the commit page, but the commit page was no longer pointing to the reader page, but as all pages were empty, the buffer is also. Fixes: 651e22f2701b ("ring-buffer: Always reset iterator to reader page") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-30tracing: Allocate the snapshot buffer before enabling probeSteven Rostedt (VMware)
commit df62db5be2e5f070ecd1a5ece5945b590ee112e0 upstream. Currently the snapshot trigger enables the probe and then allocates the snapshot. If the probe triggers before the allocation, it could cause the snapshot to fail and turn tracing off. It's best to allocate the snapshot buffer first, and then enable the trigger. If something goes wrong in the enabling of the trigger, the snapshot buffer is still allocated, but it can also be freed by the user by writting zero into the snapshot buffer file. Also add a check of the return status of alloc_snapshot(). Fixes: 77fd5c15e3 ("tracing: Add snapshot trigger to function probes") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-22ring-buffer: Fix return value check in test_ringbuffer()Wei Yongjun
commit 62277de758b155dc04b78f195a1cb5208c37b2df upstream. In case of error, the function kthread_run() returns ERR_PTR() and never returns NULL. The NULL test in the return value check should be replaced with IS_ERR(). Link: http://lkml.kernel.org/r/1466184839-14927-1-git-send-email-weiyj_lk@163.com Fixes: 6c43e554a ("ring-buffer: Add ring buffer startup selftest") Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-22ftrace: Fix removing of second function probeSteven Rostedt (VMware)
commit 82cc4fc2e70ec5baeff8f776f2773abc8b2cc0ae upstream. When two function probes are added to set_ftrace_filter, and then one of them is removed, the update to the function locations is not performed, and the record keeping of the function states are corrupted, and causes an ftrace_bug() to occur. This is easily reproducable by adding two probes, removing one, and then adding it back again. # cd /sys/kernel/debug/tracing # echo schedule:traceoff > set_ftrace_filter # echo do_IRQ:traceoff > set_ftrace_filter # echo \!do_IRQ:traceoff > /debug/tracing/set_ftrace_filter # echo do_IRQ:traceoff > set_ftrace_filter Causes: ------------[ cut here ]------------ WARNING: CPU: 2 PID: 1098 at kernel/trace/ftrace.c:2369 ftrace_get_addr_curr+0x143/0x220 Modules linked in: [...] CPU: 2 PID: 1098 Comm: bash Not tainted 4.10.0-test+ #405 Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01 v02.05 05/07/2012 Call Trace: dump_stack+0x68/0x9f __warn+0x111/0x130 ? trace_irq_work_interrupt+0xa0/0xa0 warn_slowpath_null+0x1d/0x20 ftrace_get_addr_curr+0x143/0x220 ? __fentry__+0x10/0x10 ftrace_replace_code+0xe3/0x4f0 ? ftrace_int3_handler+0x90/0x90 ? printk+0x99/0xb5 ? 0xffffffff81000000 ftrace_modify_all_code+0x97/0x110 arch_ftrace_update_code+0x10/0x20 ftrace_run_update_code+0x1c/0x60 ftrace_run_modify_code.isra.48.constprop.62+0x8e/0xd0 register_ftrace_function_probe+0x4b6/0x590 ? ftrace_startup+0x310/0x310 ? debug_lockdep_rcu_enabled.part.4+0x1a/0x30 ? update_stack_state+0x88/0x110 ? ftrace_regex_write.isra.43.part.44+0x1d3/0x320 ? preempt_count_sub+0x18/0xd0 ? mutex_lock_nested+0x104/0x800 ? ftrace_regex_write.isra.43.part.44+0x1d3/0x320 ? __unwind_start+0x1c0/0x1c0 ? _mutex_lock_nest_lock+0x800/0x800 ftrace_trace_probe_callback.isra.3+0xc0/0x130 ? func_set_flag+0xe0/0xe0 ? __lock_acquire+0x642/0x1790 ? __might_fault+0x1e/0x20 ? trace_get_user+0x398/0x470 ? strcmp+0x35/0x60 ftrace_trace_onoff_callback+0x48/0x70 ftrace_regex_write.isra.43.part.44+0x251/0x320 ? match_records+0x420/0x420 ftrace_filter_write+0x2b/0x30 __vfs_write+0xd7/0x330 ? do_loop_readv_writev+0x120/0x120 ? locks_remove_posix+0x90/0x2f0 ? do_lock_file_wait+0x160/0x160 ? __lock_is_held+0x93/0x100 ? rcu_read_lock_sched_held+0x5c/0xb0 ? preempt_count_sub+0x18/0xd0 ? __sb_start_write+0x10a/0x230 ? vfs_write+0x222/0x240 vfs_write+0xef/0x240 SyS_write+0xab/0x130 ? SyS_read+0x130/0x130 ? trace_hardirqs_on_caller+0x182/0x280 ? trace_hardirqs_on_thunk+0x1a/0x1c entry_SYSCALL_64_fastpath+0x18/0xad RIP: 0033:0x7fe61c157c30 RSP: 002b:00007ffe87890258 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: ffffffff8114a410 RCX: 00007fe61c157c30 RDX: 0000000000000010 RSI: 000055814798f5e0 RDI: 0000000000000001 RBP: ffff8800c9027f98 R08: 00007fe61c422740 R09: 00007fe61ca53700 R10: 0000000000000073 R11: 0000000000000246 R12: 0000558147a36400 R13: 00007ffe8788f160 R14: 0000000000000024 R15: 00007ffe8788f15c ? trace_hardirqs_off_caller+0xc0/0x110 ---[ end trace 99fa09b3d9869c2c ]--- Bad trampoline accounting at: ffffffff81cc3b00 (do_IRQ+0x0/0x150) Fixes: 59df055f1991 ("ftrace: trace different functions with a different tracer") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-15fgraph: Handle a case where a tracer ignores set_graph_notraceSteven Rostedt (Red Hat)
[ Upstream commit 794de08a16cf1fc1bf785dc48f66d36218cf6d88 ] Both the wakeup and irqsoff tracers can use the function graph tracer when the display-graph option is set. The problem is that they ignore the notrace file, and record the entry of functions that would be ignored by the function_graph tracer. This causes the trace->depth to be recorded into the ring buffer. The set_graph_notrace uses a trick by adding a large negative number to the trace->depth when a graph function is to be ignored. On trace output, the graph function uses the depth to record a stack of functions. But since the depth is negative, it accesses the array with a negative number and causes an out of bounds access that can cause a kernel oops or corrupt data. Have the print functions handle cases where a tracer still records functions even when they are in set_graph_notrace. Also add warnings if the depth is below zero before accessing the array. Note, the function graph logic will still prevent the return of these functions from being recorded, which means that they will be left hanging without a return. For example: # echo '*spin*' > set_graph_notrace # echo 1 > options/display-graph # echo wakeup > current_tracer # cat trace [...] _raw_spin_lock() { preempt_count_add() { do_raw_spin_lock() { update_rq_clock(); Where it should look like: _raw_spin_lock() { preempt_count_add(); do_raw_spin_lock(); } update_rq_clock(); Cc: stable@vger.kernel.org Cc: Namhyung Kim <namhyung.kim@lge.com> Fixes: 29ad23b00474 ("ftrace: Add set_graph_notrace filter") Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
2016-07-12tracing: Handle NULL formats in hold_module_trace_bprintk_format()Steven Rostedt (Red Hat)
[ Upstream commit 70c8217acd4383e069fe1898bbad36ea4fcdbdcc ] If a task uses a non constant string for the format parameter in trace_printk(), then the trace_printk_fmt variable is set to NULL. This variable is then saved in the __trace_printk_fmt section. The function hold_module_trace_bprintk_format() checks to see if duplicate formats are used by modules, and reuses them if so (saves them to the list if it is new). But this function calls lookup_format() that does a strcmp() to the value (which is now NULL) and can cause a kernel oops. This wasn't an issue till 3debb0a9ddb ("tracing: Fix trace_printk() to print when not using bprintk()") which added "__used" to the trace_printk_fmt variable, and before that, the kernel simply optimized it out (no NULL value was saved). The fix is simply to handle the NULL pointer in lookup_format() and have the caller ignore the value if it was NULL. Link: http://lkml.kernel.org/r/1464769870-18344-1-git-send-email-zhengjun.xing@intel.com Reported-by: xingzhen <zhengjun.xing@intel.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Fixes: 3debb0a9ddb ("tracing: Fix trace_printk() to print when not using bprintk()") Cc: stable@vger.kernel.org # v3.5+ Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
2016-06-06ring-buffer: Prevent overflow of size in ring_buffer_resize()Steven Rostedt (Red Hat)
[ Upstream commit 59643d1535eb220668692a5359de22545af579f6 ] If the size passed to ring_buffer_resize() is greater than MAX_LONG - BUF_PAGE_SIZE then the DIV_ROUND_UP() will return zero. Here's the details: # echo 18014398509481980 > /sys/kernel/debug/tracing/buffer_size_kb tracing_entries_write() processes this and converts kb to bytes. 18014398509481980 << 10 = 18446744073709547520 and this is passed to ring_buffer_resize() as unsigned long size. size = DIV_ROUND_UP(size, BUF_PAGE_SIZE); Where DIV_ROUND_UP(a, b) is (a + b - 1)/b BUF_PAGE_SIZE is 4080 and here 18446744073709547520 + 4080 - 1 = 18446744073709551599 where 18446744073709551599 is still smaller than 2^64 2^64 - 18446744073709551599 = 17 But now 18446744073709551599 / 4080 = 4521260802379792 and size = size * 4080 = 18446744073709551360 This is checked to make sure its still greater than 2 * 4080, which it is. Then we convert to the number of buffer pages needed. nr_page = DIV_ROUND_UP(size, BUF_PAGE_SIZE) but this time size is 18446744073709551360 and 2^64 - (18446744073709551360 + 4080 - 1) = -3823 Thus it overflows and the resulting number is less than 4080, which makes 3823 / 4080 = 0 an nr_pages is set to this. As we already checked against the minimum that nr_pages may be, this causes the logic to fail as well, and we crash the kernel. There's no reason to have the two DIV_ROUND_UP() (that's just result of historical code changes), clean up the code and fix this bug. Cc: stable@vger.kernel.org # 3.5+ Fixes: 83f40318dab00 ("ring-buffer: Make removal of ring buffer pages atomic") Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
2016-06-06ring-buffer: Use long for nr_pages to avoid overflow failuresSteven Rostedt (Red Hat)
[ Upstream commit 9b94a8fba501f38368aef6ac1b30e7335252a220 ] The size variable to change the ring buffer in ftrace is a long. The nr_pages used to update the ring buffer based on the size is int. On 64 bit machines this can cause an overflow problem. For example, the following will cause the ring buffer to crash: # cd /sys/kernel/debug/tracing # echo 10 > buffer_size_kb # echo 8556384240 > buffer_size_kb Then you get the warning of: WARNING: CPU: 1 PID: 318 at kernel/trace/ring_buffer.c:1527 rb_update_pages+0x22f/0x260 Which is: RB_WARN_ON(cpu_buffer, nr_removed); Note each ring buffer page holds 4080 bytes. This is because: 1) 10 causes the ring buffer to have 3 pages. (10kb requires 3 * 4080 pages to hold) 2) (2^31 / 2^10 + 1) * 4080 = 8556384240 The value written into buffer_size_kb is shifted by 10 and then passed to ring_buffer_resize(). 8556384240 * 2^10 = 8761737461760 3) The size passed to ring_buffer_resize() is then divided by BUF_PAGE_SIZE which is 4080. 8761737461760 / 4080 = 2147484672 4) nr_pages is subtracted from the current nr_pages (3) and we get: 2147484669. This value is saved in a signed integer nr_pages_to_update 5) 2147484669 is greater than 2^31 but smaller than 2^32, a signed int turns into the value of -2147482627 6) As the value is a negative number, in update_pages_handler() it is negated and passed to rb_remove_pages() and 2147482627 pages will be removed, which is much larger than 3 and it causes the warning because not all the pages asked to be removed were removed. Link: https://bugzilla.kernel.org/show_bug.cgi?id=118001 Cc: stable@vger.kernel.org # 2.6.28+ Fixes: 7a8e76a3829f1 ("tracing: unified trace buffer") Reported-by: Hao Qin <QEver.cn@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
2016-06-06ring-buffer: Move recursive check to per_cpu descriptorSteven Rostedt (Red Hat)
[ Upstream commit 58a09ec6e3ec88c9c7e061479f1ef7fe93324a87 ] Instead of using a global per_cpu variable to perform the recursive checks into the ring buffer, use the already existing per_cpu descriptor that is part of the ring buffer itself. Not only does this simplify the code, it also allows for one ring buffer to be used within the guts of the use of another ring buffer. For example trace_printk() can now be used within the ring buffer to record changes done by an instance into the main ring buffer. The recursion checks will prevent the trace_printk() itself from causing recursive issues with the main ring buffer (it is just ignored), but the recursive checks wont prevent the trace_printk() from recording other ring buffers. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
2016-06-06ring-buffer: Remove duplicate use of '&' in recursive codeSteven Rostedt (Red Hat)
[ Upstream commit d631c8cceb1d1d06f372878935949d421585186b ] A clean up of the recursive protection code changed val = this_cpu_read(current_context); val--; val &= this_cpu_read(current_context); to val = this_cpu_read(current_context); val &= val & (val - 1); Which has a duplicate use of '&' as the above is the same as val = val & (val - 1); Actually, it would be best to remove that line altogether and just add it to where it is used. And Christoph even mentioned that it can be further compacted to just a single line: __this_cpu_and(current_context, __this_cpu_read(current_context) - 1); Link: http://lkml.kernel.org/alpine.DEB.2.11.1503271423580.23114@gentwo.org Suggested-by: Christoph Lameter <cl@linux.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
2016-06-06ring-buffer: Add unlikelys to make fast path the defaultSteven Rostedt (Red Hat)
[ Upstream commit 3205f8063b6cc54b20d5080fb79dfcbd9c39e93d ] I was running the trace_event benchmark and noticed that the times to record a trace_event was all over the place. I looked at the assembly of the ring_buffer_lock_reserver() and saw this: <ring_buffer_lock_reserve>: 31 c0 xor %eax,%eax 48 83 3d 76 47 bd 00 cmpq $0x1,0xbd4776(%rip) # ffffffff81d10d60 <ring_buffer_flags> 01 55 push %rbp 48 89 e5 mov %rsp,%rbp 75 1d jne ffffffff8113c60d <ring_buffer_lock_reserve+0x2d> 65 ff 05 69 e3 ec 7e incl %gs:0x7eece369(%rip) # a960 <__preempt_count> 8b 47 08 mov 0x8(%rdi),%eax 85 c0 test %eax,%eax +---- 74 12 je ffffffff8113c610 <ring_buffer_lock_reserve+0x30> | 65 ff 0d 5b e3 ec 7e decl %gs:0x7eece35b(%rip) # a960 <__preempt_count> | 0f 84 85 00 00 00 je ffffffff8113c690 <ring_buffer_lock_reserve+0xb0> | 31 c0 xor %eax,%eax | 5d pop %rbp | c3 retq | 90 nop +---> 65 44 8b 05 48 e3 ec mov %gs:0x7eece348(%rip),%r8d # a960 <__preempt_count> 7e 41 81 e0 ff ff ff 7f and $0x7fffffff,%r8d b0 08 mov $0x8,%al 65 8b 0d 58 36 ed 7e mov %gs:0x7eed3658(%rip),%ecx # fc80 <current_context> 41 f7 c0 00 ff 1f 00 test $0x1fff00,%r8d 74 1e je ffffffff8113c64f <ring_buffer_lock_reserve+0x6f> 41 f7 c0 00 00 10 00 test $0x100000,%r8d b0 01 mov $0x1,%al 75 13 jne ffffffff8113c64f <ring_buffer_lock_reserve+0x6f> 41 81 e0 00 00 0f 00 and $0xf0000,%r8d 49 83 f8 01 cmp $0x1,%r8 19 c0 sbb %eax,%eax 83 e0 02 and $0x2,%eax 83 c0 02 add $0x2,%eax 85 c8 test %ecx,%eax 75 ab jne ffffffff8113c5fe <ring_buffer_lock_reserve+0x1e> 09 c8 or %ecx,%eax 65 89 05 24 36 ed 7e mov %eax,%gs:0x7eed3624(%rip) # fc80 <current_context> The arrow is the fast path. After adding the unlikely's, the fast path looks a bit better: <ring_buffer_lock_reserve>: 31 c0 xor %eax,%eax 48 83 3d 76 47 bd 00 cmpq $0x1,0xbd4776(%rip) # ffffffff81d10d60 <ring_buffer_flags> 01 55 push %rbp 48 89 e5 mov %rsp,%rbp 75 7b jne ffffffff8113c66b <ring_buffer_lock_reserve+0x8b> 65 ff 05 69 e3 ec 7e incl %gs:0x7eece369(%rip) # a960 <__preempt_count> 8b 47 08 mov 0x8(%rdi),%eax 85 c0 test %eax,%eax 0f 85 9f 00 00 00 jne ffffffff8113c6a1 <ring_buffer_lock_reserve+0xc1> 65 8b 0d 57 e3 ec 7e mov %gs:0x7eece357(%rip),%ecx # a960 <__preempt_count> 81 e1 ff ff ff 7f and $0x7fffffff,%ecx b0 08 mov $0x8,%al 65 8b 15 68 36 ed 7e mov %gs:0x7eed3668(%rip),%edx # fc80 <current_context> f7 c1 00 ff 1f 00 test $0x1fff00,%ecx 75 50 jne ffffffff8113c670 <ring_buffer_lock_reserve+0x90> 85 d0 test %edx,%eax 75 7d jne ffffffff8113c6a1 <ring_buffer_lock_reserve+0xc1> 09 d0 or %edx,%eax 65 89 05 53 36 ed 7e mov %eax,%gs:0x7eed3653(%rip) # fc80 <current_context> 65 8b 05 fc da ec 7e mov %gs:0x7eecdafc(%rip),%eax # a130 <cpu_number> 89 c2 mov %eax,%edx Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
2016-05-17tracing: Don't display trigger file for events that can't be enabledChunyu Hu
[ Upstream commit 854145e0a8e9a05f7366d240e2f99d9c1ca6d6dd ] Currently register functions for events will be called through the 'reg' field of event class directly without any check when seting up triggers. Triggers for events that don't support register through debug fs (events under events/ftrace are for trace-cmd to read event format, and most of them don't have a register function except events/ftrace/functionx) can't be enabled at all, and an oops will be hit when setting up trigger for those events, so just not creating them is an easy way to avoid the oops. Link: http://lkml.kernel.org/r/1462275274-3911-1-git-send-email-chuhu@redhat.com Cc: stable@vger.kernel.org # 3.14+ Fixes: 85f2b08268c01 ("tracing: Add basic event trigger framework") Signed-off-by: Chunyu Hu <chuhu@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
2016-04-18tracing: Fix trace_printk() to print when not using bprintk()Steven Rostedt (Red Hat)
[ Upstream commit 3debb0a9ddb16526de8b456491b7db60114f7b5e ] The trace_printk() code will allocate extra buffers if the compile detects that a trace_printk() is used. To do this, the format of the trace_printk() is saved to the __trace_printk_fmt section, and if that section is bigger than zero, the buffers are allocated (along with a message that this has happened). If trace_printk() uses a format that is not a constant, and thus something not guaranteed to be around when the print happens, the compiler optimizes the fmt out, as it is not used, and the __trace_printk_fmt section is not filled. This means the kernel will not allocate the special buffers needed for the trace_printk() and the trace_printk() will not write anything to the tracing buffer. Adding a "__used" to the variable in the __trace_printk_fmt section will keep it around, even though it is set to NULL. This will keep the string from being printed in the debugfs/tracing/printk_formats section as it is not needed. Reported-by: Vlastimil Babka <vbabka@suse.cz> Fixes: 07d777fe8c398 "tracing: Add percpu buffers for trace_printk()" Cc: stable@vger.kernel.org # v3.5+ Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
2016-04-18tracing: Fix crash from reading trace_pipe with sendfileSteven Rostedt (Red Hat)
[ Upstream commit a29054d9478d0435ab01b7544da4f674ab13f533 ] If tracing contains data and the trace_pipe file is read with sendfile(), then it can trigger a NULL pointer dereference and various BUG_ON within the VM code. There's a patch to fix this in the splice_to_pipe() code, but it's also a good idea to not let that happen from trace_pipe either. Link: http://lkml.kernel.org/r/1457641146-9068-1-git-send-email-rabin@rab.in Cc: stable@vger.kernel.org # 2.6.30+ Reported-by: Rabin Vincent <rabin.vincent@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
2016-03-10tracing: Fix showing function event in available_eventsSteven Rostedt (Red Hat)
[ Upstream commit d045437a169f899dfb0f6f7ede24cc042543ced9 ] The ftrace:function event is only displayed for parsing the function tracer data. It is not used to enable function tracing, and does not include an "enable" file in its event directory. Originally, this event was kept separate from other events because it did not have a ->reg parameter. But perf added a "reg" parameter for its use which caused issues, because it made the event available to functions where it was not compatible for. Commit 9b63776fa3ca9 "tracing: Do not enable function event with enable" added a TRACE_EVENT_FL_IGNORE_ENABLE flag that prevented the function event from being enabled by normal trace events. But this commit missed keeping the function event from being displayed by the "available_events" directory, which is used to show what events can be enabled by set_event. One documented way to enable all events is to: cat available_events > set_event But because the function event is displayed in the available_events, this now causes an INVALID error: cat: write error: Invalid argument Reported-by: Chunyu Hu <chuhu@redhat.com> Fixes: 9b63776fa3ca9 "tracing: Do not enable function event with enable" Cc: stable@vger.kernel.org # 3.4+ Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
2015-08-04tracing: Have branch tracer use recursive field of task structSteven Rostedt (Red Hat)
[ Upstream commit 6224beb12e190ff11f3c7d4bf50cb2922878f600 ] Fengguang Wu's tests triggered a bug in the branch tracer's start up test when CONFIG_DEBUG_PREEMPT set. This was because that config adds some debug logic in the per cpu field, which calls back into the branch tracer. The branch tracer has its own recursive checks, but uses a per cpu variable to implement it. If retrieving the per cpu variable calls back into the branch tracer, you can see how things will break. Instead of using a per cpu variable, use the trace_recursion field of the current task struct. Simply set a bit when entering the branch tracing and clear it when leaving. If the bit is set on entry, just don't do the tracing. There's also the case with lockdep, as the local_irq_save() called before the recursion can also trigger code that can call back into the function. Changing that to a raw_local_irq_save() will protect that as well. This prevents the recursion and the inevitable crash that follows. Link: http://lkml.kernel.org/r/20150630141803.GA28071@wfg-t540p.sh.intel.com Cc: stable@vger.kernel.org # 3.10+ Reported-by: Fengguang Wu <fengguang.wu@intel.com> Tested-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
2015-08-04tracing/filter: Do not WARN on operand count going below zeroSteven Rostedt (Red Hat)
[ Upstream commit b4875bbe7e68f139bd3383828ae8e994a0df6d28 ] When testing the fix for the trace filter, I could not come up with a scenario where the operand count goes below zero, so I added a WARN_ON_ONCE(cnt < 0) to the logic. But there is legitimate case that it can happen (although the filter would be wrong). # echo '>' > /sys/kernel/debug/events/ext4/ext4_truncate_exit/filter That is, a single operation without any operands will hit the path where the WARN_ON_ONCE() can trigger. Although this is harmless, and the filter is reported as a error. But instead of spitting out a warning to the kernel dmesg, just fail nicely and report it via the proper channels. Link: http://lkml.kernel.org/r/558C6082.90608@oracle.com Reported-by: Vince Weaver <vincent.weaver@maine.edu> Reported-by: Sasha Levin <sasha.levin@oracle.com> Cc: stable@vger.kernel.org # 2.6.33+ Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
2015-07-13tracing: Have filter check for balanced opsSteven Rostedt
[ Upstream commit 2cf30dc180cea808077f003c5116388183e54f9e ] When the following filter is used it causes a warning to trigger: # cd /sys/kernel/debug/tracing # echo "((dev==1)blocks==2)" > events/ext4/ext4_truncate_exit/filter -bash: echo: write error: Invalid argument # cat events/ext4/ext4_truncate_exit/filter ((dev==1)blocks==2) ^ parse_error: No error ------------[ cut here ]------------ WARNING: CPU: 2 PID: 1223 at kernel/trace/trace_events_filter.c:1640 replace_preds+0x3c5/0x990() Modules linked in: bnep lockd grace bluetooth ... CPU: 3 PID: 1223 Comm: bash Tainted: G W 4.1.0-rc3-test+ #450 Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01 v02.05 05/07/2012 0000000000000668 ffff8800c106bc98 ffffffff816ed4f9 ffff88011ead0cf0 0000000000000000 ffff8800c106bcd8 ffffffff8107fb07 ffffffff8136b46c ffff8800c7d81d48 ffff8800d4c2bc00 ffff8800d4d4f920 00000000ffffffea Call Trace: [<ffffffff816ed4f9>] dump_stack+0x4c/0x6e [<ffffffff8107fb07>] warn_slowpath_common+0x97/0xe0 [<ffffffff8136b46c>] ? _kstrtoull+0x2c/0x80 [<ffffffff8107fb6a>] warn_slowpath_null+0x1a/0x20 [<ffffffff81159065>] replace_preds+0x3c5/0x990 [<ffffffff811596b2>] create_filter+0x82/0xb0 [<ffffffff81159944>] apply_event_filter+0xd4/0x180 [<ffffffff81152bbf>] event_filter_write+0x8f/0x120 [<ffffffff811db2a8>] __vfs_write+0x28/0xe0 [<ffffffff811dda43>] ? __sb_start_write+0x53/0xf0 [<ffffffff812e51e0>] ? security_file_permission+0x30/0xc0 [<ffffffff811dc408>] vfs_write+0xb8/0x1b0 [<ffffffff811dc72f>] SyS_write+0x4f/0xb0 [<ffffffff816f5217>] system_call_fastpath+0x12/0x6a ---[ end trace e11028bd95818dcd ]--- Worse yet, reading the error message (the filter again) it says that there was no error, when there clearly was. The issue is that the code that checks the input does not check for balanced ops. That is, having an op between a closed parenthesis and the next token. This would only cause a warning, and fail out before doing any real harm, but it should still not caues a warning, and the error reported should work: # cd /sys/kernel/debug/tracing # echo "((dev==1)blocks==2)" > events/ext4/ext4_truncate_exit/filter -bash: echo: write error: Invalid argument # cat events/ext4/ext4_truncate_exit/filter ((dev==1)blocks==2) ^ parse_error: Meaningless filter expression And give no kernel warning. Link: http://lkml.kernel.org/r/20150615175025.7e809215@gandalf.local.home Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: stable@vger.kernel.org # 2.6.31+ Reported-by: Vince Weaver <vincent.weaver@maine.edu> Tested-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
2015-07-05tracing/filter: Do not allow infix to exceed end of stringSteven Rostedt (Red Hat)
[ Upstream commit 6b88f44e161b9ee2a803e5b2b1fbcf4e20e8b980 ] While debugging a WARN_ON() for filtering, I found that it is possible for the filter string to be referenced after its end. With the filter: # echo '>' > /sys/kernel/debug/events/ext4/ext4_truncate_exit/filter The filter_parse() function can call infix_get_op() which calls infix_advance() that updates the infix filter pointers for the cnt and tail without checking if the filter is already at the end, which will put the cnt to zero and the tail beyond the end. The loop then calls infix_next() that has ps->infix.cnt--; return ps->infix.string[ps->infix.tail++]; The cnt will now be below zero, and the tail that is returned is already passed the end of the filter string. So far the allocation of the filter string usually has some buffer that is zeroed out, but if the filter string is of the exact size of the allocated buffer there's no guarantee that the charater after the nul terminating character will be zero. Luckily, only root can write to the filter. Cc: stable@vger.kernel.org # 2.6.33+ Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
generated by cgit v1.2.3 (git 2.46.0) at 2026-01-06 11:22:15 +0000