user/sven/linux.git/kernel/trace/trace_stack.c, branch v4.1.15

tracing: remove use of seq_printf return value

2015-04-15T23:35:25Z

The seq_printf return value, because it's frequently misused, will eventually be converted to void. See: commit 1f33c41c03da ("seq_file: Rename seq_overflow() to seq_has_overflowed() and make public") Miscellanea: o Remove unused return value from trace_lookup_stack Signed-off-by: Joe Perches Acked-by: Steven Rostedt Cc: Al Viro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

tracing: Use IS_ERR() check for return value of tracing_init_dentry()

2015-01-22T16:19:49Z

tracing_init_dentry() will soon return NULL as a valid pointer for the top level tracing directroy. NULL can not be used as an error value. Instead, switch to ERR_PTR() and check the return status with IS_ERR(). Signed-off-by: Steven Rostedt

tracing: Remove unneeded includes of debugfs.h and fs.h

2015-01-22T16:19:48Z

The creation of tracing files and directories is for the most part encapsulated in helper functions in trace.c. Other files do not need to include debugfs.h or fs.h, as they may have needed to in the past. Remove them from the files that do not need them. Signed-off-by: Steven Rostedt

sched: Add helper for task stack page overrun checking

2014-09-19T10:35:23Z

This facility is used in a few places so let's introduce a helper function to improve code readability. Signed-off-by: Aaron Tomlin Signed-off-by: Peter Zijlstra (Intel) Cc: aneesh.kumar@linux.vnet.ibm.com Cc: dzickus@redhat.com Cc: bmr@redhat.com Cc: jcastillo@redhat.com Cc: oleg@redhat.com Cc: riel@redhat.com Cc: prarit@redhat.com Cc: jgh@redhat.com Cc: minchan@kernel.org Cc: mpe@ellerman.id.au Cc: tglx@linutronix.de Cc: hannes@cmpxchg.org Cc: Andrew Morton Cc: Benjamin Herrenschmidt Cc: Jiri Olsa Cc: Linus Torvalds Cc: Masami Hiramatsu Cc: Michael Ellerman Cc: Paul Mackerras Cc: Seiji Aguchi Cc: Steven Rostedt Cc: Yasuaki Ishimatsu Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/1410527779-8133-3-git-send-email-atomlin@redhat.com Signed-off-by: Ingo Molnar

init/main.c: Give init_task a canary

2014-09-19T10:35:22Z

Tasks get their end of stack set to STACK_END_MAGIC with the aim to catch stack overruns. Currently this feature does not apply to init_task. This patch removes this restriction. Note that a similar patch was posted by Prarit Bhargava some time ago but was never merged: http://marc.info/?l=linux-kernel&m=127144305403241&w=2 Signed-off-by: Aaron Tomlin Signed-off-by: Peter Zijlstra (Intel) Acked-by: Oleg Nesterov Acked-by: Michael Ellerman Cc: aneesh.kumar@linux.vnet.ibm.com Cc: dzickus@redhat.com Cc: bmr@redhat.com Cc: jcastillo@redhat.com Cc: jgh@redhat.com Cc: minchan@kernel.org Cc: tglx@linutronix.de Cc: hannes@cmpxchg.org Cc: Alex Thorlton Cc: Andrew Morton Cc: Benjamin Herrenschmidt Cc: Daeseok Youn Cc: David Rientjes Cc: Fabian Frederick Cc: Geert Uytterhoeven Cc: Jiri Olsa Cc: Kees Cook Cc: Kirill A. Shutemov Cc: Linus Torvalds Cc: Masami Hiramatsu Cc: Michael Opdenacker Cc: Paul Mackerras Cc: Prarit Bhargava Cc: Rik van Riel Cc: Rusty Russell Cc: Seiji Aguchi Cc: Steven Rostedt Cc: Vladimir Davydov Cc: Yasuaki Ishimatsu Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/1410527779-8133-2-git-send-email-atomlin@redhat.com Signed-off-by: Ingo Molnar

tracing: Print max callstack on stacktrace bug

2014-06-02T20:43:49Z

While I played with my own feature(ex, something on the way to reclaim), the kernel would easily oops. I guessed that the reason had to do with stack overflow and wanted to prove it. I discovered the stack tracer which proved to be very useful for me but the kernel would oops before my user program gather the information via "watch cat /sys/kernel/debug/tracing/stack_trace" so I couldn't get any message from that. What I needed was to have the stack tracer emit the kernel stack usage before it does the oops so I could find what was hogging the stack. This patch shows the callstack of max stack usage right before an oops so we can find a culprit. So, the result is as follows. [ 1116.522206] init: lightdm main process (1246) terminated with status 1 [ 1119.922916] init: failsafe-x main process (1272) terminated with status 1 [ 3887.728131] kworker/u24:1 (6637) used greatest stack depth: 256 bytes left [ 6397.629227] cc1 (9554) used greatest stack depth: 128 bytes left [ 7174.467392] Depth Size Location (47 entries) [ 7174.467392] ----- ---- -------- [ 7174.467785] 0) 7248 256 get_page_from_freelist+0xa7/0x920 [ 7174.468506] 1) 6992 352 __alloc_pages_nodemask+0x1cd/0xb20 [ 7174.469224] 2) 6640 8 alloc_pages_current+0x10f/0x1f0 [ 7174.469413] 3) 6632 168 new_slab+0x2c5/0x370 [ 7174.469413] 4) 6464 8 __slab_alloc+0x3a9/0x501 [ 7174.469413] 5) 6456 80 __kmalloc+0x1cb/0x200 [ 7174.469413] 6) 6376 376 vring_add_indirect+0x36/0x200 [ 7174.469413] 7) 6000 144 virtqueue_add_sgs+0x2e2/0x320 [ 7174.469413] 8) 5856 288 __virtblk_add_req+0xda/0x1b0 [ 7174.469413] 9) 5568 96 virtio_queue_rq+0xd3/0x1d0 [ 7174.469413] 10) 5472 128 __blk_mq_run_hw_queue+0x1ef/0x440 [ 7174.469413] 11) 5344 16 blk_mq_run_hw_queue+0x35/0x40 [ 7174.469413] 12) 5328 96 blk_mq_insert_requests+0xdb/0x160 [ 7174.469413] 13) 5232 112 blk_mq_flush_plug_list+0x12b/0x140 [ 7174.469413] 14) 5120 112 blk_flush_plug_list+0xc7/0x220 [ 7174.469413] 15) 5008 64 io_schedule_timeout+0x88/0x100 [ 7174.469413] 16) 4944 128 mempool_alloc+0x145/0x170 [ 7174.469413] 17) 4816 96 bio_alloc_bioset+0x10b/0x1d0 [ 7174.469413] 18) 4720 48 get_swap_bio+0x30/0x90 [ 7174.469413] 19) 4672 160 __swap_writepage+0x150/0x230 [ 7174.469413] 20) 4512 32 swap_writepage+0x42/0x90 [ 7174.469413] 21) 4480 320 shrink_page_list+0x676/0xa80 [ 7174.469413] 22) 4160 208 shrink_inactive_list+0x262/0x4e0 [ 7174.469413] 23) 3952 304 shrink_lruvec+0x3e1/0x6a0 [ 7174.469413] 24) 3648 80 shrink_zone+0x3f/0x110 [ 7174.469413] 25) 3568 128 do_try_to_free_pages+0x156/0x4c0 [ 7174.469413] 26) 3440 208 try_to_free_pages+0xf7/0x1e0 [ 7174.469413] 27) 3232 352 __alloc_pages_nodemask+0x783/0xb20 [ 7174.469413] 28) 2880 8 alloc_pages_current+0x10f/0x1f0 [ 7174.469413] 29) 2872 200 __page_cache_alloc+0x13f/0x160 [ 7174.469413] 30) 2672 80 find_or_create_page+0x4c/0xb0 [ 7174.469413] 31) 2592 80 ext4_mb_load_buddy+0x1e9/0x370 [ 7174.469413] 32) 2512 176 ext4_mb_regular_allocator+0x1b7/0x460 [ 7174.469413] 33) 2336 128 ext4_mb_new_blocks+0x458/0x5f0 [ 7174.469413] 34) 2208 256 ext4_ext_map_blocks+0x70b/0x1010 [ 7174.469413] 35) 1952 160 ext4_map_blocks+0x325/0x530 [ 7174.469413] 36) 1792 384 ext4_writepages+0x6d1/0xce0 [ 7174.469413] 37) 1408 16 do_writepages+0x23/0x40 [ 7174.469413] 38) 1392 96 __writeback_single_inode+0x45/0x2e0 [ 7174.469413] 39) 1296 176 writeback_sb_inodes+0x2ad/0x500 [ 7174.469413] 40) 1120 80 __writeback_inodes_wb+0x9e/0xd0 [ 7174.469413] 41) 1040 160 wb_writeback+0x29b/0x350 [ 7174.469413] 42) 880 208 bdi_writeback_workfn+0x11c/0x480 [ 7174.469413] 43) 672 144 process_one_work+0x1d2/0x570 [ 7174.469413] 44) 528 112 worker_thread+0x116/0x370 [ 7174.469413] 45) 416 240 kthread+0xf3/0x110 [ 7174.469413] 46) 176 176 ret_from_fork+0x7c/0xb0 [ 7174.469413] ------------[ cut here ]------------ [ 7174.469413] kernel BUG at kernel/trace/trace_stack.c:174! [ 7174.469413] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC [ 7174.469413] Dumping ftrace buffer: [ 7174.469413] (ftrace buffer empty) [ 7174.469413] Modules linked in: [ 7174.469413] CPU: 0 PID: 440 Comm: kworker/u24:0 Not tainted 3.14.0+ #212 [ 7174.469413] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 7174.469413] Workqueue: writeback bdi_writeback_workfn (flush-253:0) [ 7174.469413] task: ffff880034170000 ti: ffff880029518000 task.ti: ffff880029518000 [ 7174.469413] RIP: 0010:[] [] stack_trace_call+0x2de/0x340 [ 7174.469413] RSP: 0000:ffff880029518290 EFLAGS: 00010046 [ 7174.469413] RAX: 0000000000000030 RBX: 000000000000002f RCX: 0000000000000000 [ 7174.469413] RDX: 0000000000000000 RSI: 000000000000002f RDI: ffffffff810b7159 [ 7174.469413] RBP: ffff8800295182f0 R08: ffffffffffffffff R09: 0000000000000000 [ 7174.469413] R10: 0000000000000001 R11: 0000000000000001 R12: ffffffff82768dfc [ 7174.469413] R13: 000000000000f2e8 R14: ffff8800295182b8 R15: 00000000000000f8 [ 7174.469413] FS: 0000000000000000(0000) GS:ffff880037c00000(0000) knlGS:0000000000000000 [ 7174.469413] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 7174.469413] CR2: 00002acd0b994000 CR3: 0000000001c0b000 CR4: 00000000000006f0 [ 7174.469413] Stack: [ 7174.469413] 0000000000000000 ffffffff8114fdb7 0000000000000087 0000000000001c50 [ 7174.469413] 0000000000000000 0000000000000000 0000000000000000 0000000000000000 [ 7174.469413] 0000000000000002 ffff880034170000 ffff880034171028 0000000000000000 [ 7174.469413] Call Trace: [ 7174.469413] [] ? get_page_from_freelist+0xa7/0x920 [ 7174.469413] [] ftrace_call+0x5/0x2f [ 7174.469413] [] ? next_zones_zonelist+0x5/0x70 [ 7174.469413] [] ? __bfs+0x11a/0x270 [ 7174.469413] [] ? next_zones_zonelist+0x5/0x70 [ 7174.469413] [] ? get_page_from_freelist+0xa7/0x920 [ 7174.469413] [] ? alloc_pages_current+0x10f/0x1f0 [ 7174.469413] [] __alloc_pages_nodemask+0x1cd/0xb20 [ 7174.469413] [] ? check_irq_usage+0x96/0xe0 [ 7174.469413] [] ? ftrace_call+0x5/0x2f [ 7174.469413] [] alloc_pages_current+0x10f/0x1f0 [ 7174.469413] [] ? new_slab+0x2c5/0x370 [ 7174.469413] [] new_slab+0x2c5/0x370 [ 7174.469413] [] ? ftrace_call+0x5/0x2f [ 7174.469413] [] __slab_alloc+0x3a9/0x501 [ 7174.469413] [] ? __kmalloc+0x1cb/0x200 [ 7174.469413] [] ? vring_add_indirect+0x36/0x200 [ 7174.469413] [] ? vring_add_indirect+0x36/0x200 [ 7174.469413] [] ? vring_add_indirect+0x36/0x200 [ 7174.469413] [] __kmalloc+0x1cb/0x200 [ 7174.469413] [] ? vring_add_indirect+0x200/0x200 [ 7174.469413] [] vring_add_indirect+0x36/0x200 [ 7174.469413] [] virtqueue_add_sgs+0x2e2/0x320 [ 7174.469413] [] __virtblk_add_req+0xda/0x1b0 [ 7174.469413] [] virtio_queue_rq+0xd3/0x1d0 [ 7174.469413] [] __blk_mq_run_hw_queue+0x1ef/0x440 [ 7174.469413] [] blk_mq_run_hw_queue+0x35/0x40 [ 7174.469413] [] blk_mq_insert_requests+0xdb/0x160 [ 7174.469413] [] blk_mq_flush_plug_list+0x12b/0x140 [ 7174.469413] [] blk_flush_plug_list+0xc7/0x220 [ 7174.469413] [] ? _raw_spin_unlock_irqrestore+0x3f/0x70 [ 7174.469413] [] io_schedule_timeout+0x88/0x100 [ 7174.469413] [] ? io_schedule_timeout+0x5/0x100 [ 7174.469413] [] mempool_alloc+0x145/0x170 [ 7174.469413] [] ? __init_waitqueue_head+0x60/0x60 [ 7174.469413] [] bio_alloc_bioset+0x10b/0x1d0 [ 7174.469413] [] ? end_swap_bio_read+0xc0/0xc0 [ 7174.469413] [] ? end_swap_bio_read+0xc0/0xc0 [ 7174.469413] [] get_swap_bio+0x30/0x90 [ 7174.469413] [] ? end_swap_bio_read+0xc0/0xc0 [ 7174.469413] [] __swap_writepage+0x150/0x230 [ 7174.469413] [] ? do_raw_spin_unlock+0x5/0xa0 [ 7174.469413] [] ? end_swap_bio_read+0xc0/0xc0 [ 7174.469413] [] ? __swap_writepage+0x5/0x230 [ 7174.469413] [] swap_writepage+0x42/0x90 [ 7174.469413] [] shrink_page_list+0x676/0xa80 [ 7174.469413] [] ? ftrace_call+0x5/0x2f [ 7174.469413] [] shrink_inactive_list+0x262/0x4e0 [ 7174.469413] [] shrink_lruvec+0x3e1/0x6a0 [ 7174.469413] [] shrink_zone+0x3f/0x110 [ 7174.469413] [] ? ftrace_call+0x5/0x2f [ 7174.469413] [] do_try_to_free_pages+0x156/0x4c0 [ 7174.469413] [] try_to_free_pages+0xf7/0x1e0 [ 7174.469413] [] __alloc_pages_nodemask+0x783/0xb20 [ 7174.469413] [] alloc_pages_current+0x10f/0x1f0 [ 7174.469413] [] ? __page_cache_alloc+0x13f/0x160 [ 7174.469413] [] __page_cache_alloc+0x13f/0x160 [ 7174.469413] [] find_or_create_page+0x4c/0xb0 [ 7174.469413] [] ? find_get_page+0x5/0x130 [ 7174.469413] [] ext4_mb_load_buddy+0x1e9/0x370 [ 7174.469413] [] ext4_mb_regular_allocator+0x1b7/0x460 [ 7174.469413] [] ? ext4_mb_use_preallocated+0x40/0x360 [ 7174.469413] [] ? ftrace_call+0x5/0x2f [ 7174.469413] [] ext4_mb_new_blocks+0x458/0x5f0 [ 7174.469413] [] ext4_ext_map_blocks+0x70b/0x1010 [ 7174.469413] [] ext4_map_blocks+0x325/0x530 [ 7174.469413] [] ext4_writepages+0x6d1/0xce0 [ 7174.469413] [] ? ext4_journalled_write_end+0x330/0x330 [ 7174.469413] [] do_writepages+0x23/0x40 [ 7174.469413] [] __writeback_single_inode+0x45/0x2e0 [ 7174.469413] [] writeback_sb_inodes+0x2ad/0x500 [ 7174.469413] [] __writeback_inodes_wb+0x9e/0xd0 [ 7174.469413] [] wb_writeback+0x29b/0x350 [ 7174.469413] [] ? __local_bh_enable_ip+0x6d/0xd0 [ 7174.469413] [] bdi_writeback_workfn+0x11c/0x480 [ 7174.469413] [] ? process_one_work+0x170/0x570 [ 7174.469413] [] process_one_work+0x1d2/0x570 [ 7174.469413] [] ? process_one_work+0x170/0x570 [ 7174.469413] [] worker_thread+0x116/0x370 [ 7174.469413] [] ? manage_workers.isra.19+0x2e0/0x2e0 [ 7174.469413] [] kthread+0xf3/0x110 [ 7174.469413] [] ? flush_kthread_worker+0x150/0x150 [ 7174.469413] [] ret_from_fork+0x7c/0xb0 [ 7174.469413] [] ? flush_kthread_worker+0x150/0x150 [ 7174.469413] Code: c0 49 bc fc 8d 76 82 ff ff ff ff e8 44 5a 5b 00 31 f6 8b 05 95 2b b3 00 48 39 c6 7d 0e 4c 8b 04 f5 20 5f c5 81 49 83 f8 ff 75 11 <0f> 0b 48 63 05 71 5a 64 01 48 29 c3 e9 d0 fd ff ff 48 8d 5e 01 [ 7174.469413] RIP [] stack_trace_call+0x2de/0x340 [ 7174.469413] RSP [ 7174.469413] ---[ end trace c97d325b36b718f3 ]--- Link: http://lkml.kernel.org/p/1401683592-1651-1-git-send-email-minchan@kernel.org Signed-off-by: Minchan Kim Signed-off-by: Steven Rostedt

tracing/stack_trace: Skip 4 instead of 3 when using ftrace_ops_list_func

2014-04-24T17:36:03Z

When using ftrace_ops_list_func, we should skip 4 instead of 3, to avoid ftrace_call+0x5/0xb appearing in the stack trace: Depth Size Location (110 entries) ----- ---- -------- 0) 2956 0 update_curr+0xe/0x1e0 1) 2956 68 ftrace_call+0x5/0xb 2) 2888 92 enqueue_entity+0x53/0xe80 3) 2796 80 enqueue_task_fair+0x47/0x7e0 4) 2716 28 enqueue_task+0x45/0x70 5) 2688 12 activate_task+0x22/0x30 Add a function using_ftrace_ops_list_func() to test for this while keeping ftrace_ops_list_func to remain static. Link: http://lkml.kernel.org/p/1398006644-5935-2-git-send-email-wangjiaxing@insigma.com.cn Signed-off-by: Jiaxing Wang Signed-off-by: Steven Rostedt

tracing: Add BUG_ON when stack end location is over written

2014-03-24T14:39:11Z

It is difficult to detect a stack overrun when it actually occurs. We have observed that this type of corruption is often silent and can go unnoticed. Once the corrupted region is examined, the outcome is undefined and often results in sporadic system crashes. When the stack tracing feature is enabled, let's check for this condition and take appropriate action. Note: init_task doesn't get its stack end location set to STACK_END_MAGIC. Link: http://lkml.kernel.org/r/1395669837-30209-1-git-send-email-atomlin@redhat.com Signed-off-by: Aaron Tomlin Signed-off-by: Steven Rostedt

tracing: Add generic tracing_lseek() function

2014-01-02T21:17:12Z

Trace event triggers added a lseek that uses the ftrace_filter_lseek() function. Unfortunately, when function tracing is not configured in that function is not defined and the kernel fails to build. This is the second time that function was added to a file ops and it broke the build due to requiring special config dependencies. Make a generic tracing_lseek() that all the tracing utilities may use. Also, modify the old ftrace_filter_lseek() to return 0 instead of 1 on WRONLY. Not sure why it was a 1 as that does not make sense. This also changes the old tracing_seek() to modify the file pos pointer on WRONLY as well. Reported-by: kbuild test robot Tested-by: Tom Zanussi Acked-by: Tom Zanussi Signed-off-by: Steven Rostedt

Merge tag 'trace-3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2013-04-29T20:55:38Z

Pull tracing updates from Steven Rostedt: "Along with the usual minor fixes and clean ups there are a few major changes with this pull request. 1) Multiple buffers for the ftrace facility This feature has been requested by many people over the last few years. I even heard that Google was about to implement it themselves. I finally had time and cleaned up the code such that you can now create multiple instances of the ftrace buffer and have different events go to different buffers. This way, a low frequency event will not be lost in the noise of a high frequency event. Note, currently only events can go to different buffers, the tracers (ie function, function_graph and the latency tracers) still can only be written to the main buffer. 2) The function tracer triggers have now been extended. The function tracer had two triggers. One to enable tracing when a function is hit, and one to disable tracing. Now you can record a stack trace on a single (or many) function(s), take a snapshot of the buffer (copy it to the snapshot buffer), and you can enable or disable an event to be traced when a function is hit. 3) A perf clock has been added. A "perf" clock can be chosen to be used when tracing. This will cause ftrace to use the same clock as perf uses, and hopefully this will make it easier to interleave the perf and ftrace data for analysis." * tag 'trace-3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (82 commits) tracepoints: Prevent null probe from being added tracing: Compare to 1 instead of zero for is_signed_type() tracing: Remove obsolete macro guard _TRACE_PROFILE_INIT ftrace: Get rid of ftrace_profile_bits tracing: Check return value of tracing_init_dentry() tracing: Get rid of unneeded key calculation in ftrace_hash_move() tracing: Reset ftrace_graph_filter_enabled if count is zero tracing: Fix off-by-one on allocating stat->pages kernel: tracing: Use strlcpy instead of strncpy tracing: Update debugfs README file tracing: Fix ftrace_dump() tracing: Rename trace_event_mutex to trace_event_sem tracing: Fix comment about prefix in arch_syscall_match_sym_name() tracing: Convert trace_destroy_fields() to static tracing: Move find_event_field() into trace_events.c tracing: Use TRACE_MAX_PRINT instead of constant tracing: Use pr_warn_once instead of open coded implementation ring-buffer: Add ring buffer startup selftest tracing: Bring Documentation/trace/ftrace.txt up to date tracing: Add "perf" trace_clock ... Conflicts: kernel/trace/ftrace.c kernel/trace/trace.c