Commit Graph

4 Commits

Author SHA1 Message Date
Josh Poimboeuf
53938ee427 scripts/decode_stacktrace.sh: Fix address line detection on x86
Kirill reported that the decode_stacktrace.sh script was broken by the
following commit:

  bb5e5ce545 ("x86/dumpstack: Remove kernel text addresses from stack dump")

Fix it by updating the per-line absolute address check to also check for
function-based address lines like the following:

  write_sysrq_trigger+0x51/0x60

I didn't remove the check for absolute addresses because it's still
needed for ARM.

Reported-by: Kirill A. Shutemov <kirill@shutemov.name>
Tested-by: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sasha Levin <alexander.levin@verizon.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: bb5e5ce545 ("x86/dumpstack: Remove kernel text addresses from stack dump")
Link: http://lkml.kernel.org/r/20161128230635.4n2ofgawltgexgcg@treble
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-11-29 14:19:50 +01:00
Konstantin Khlebnikov
310c6dd06a scripts/decode_stacktrace.sh: handle symbols in modules
scripts/decode_stacktrace.sh presently displays module symbols as

	func+0x0ff/0x5153 [module]

Add a third argument: the pathname of a directory where the script
should look for the file module.ko so that the output appears as

	func (foo/bar.c:123) module

Without the argument or if the module file isn't found the script prints
such symbols as is without decoding.

Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
Robert Jarzmik
e260fe01fa scripts: decode_stacktrace: fix ARM architecture decoding
Fix the stack decoder for the ARM architecture.
An ARM stack is designed as :

[   81.547704] [<c023eb04>] (bucket_find_contain) from [<c023ec88>] (check_sync+0x40/0x4f8)
[   81.559668] [<c023ec88>] (check_sync) from [<c023f8c4>] (debug_dma_sync_sg_for_cpu+0x128/0x194)
[   81.571583] [<c023f8c4>] (debug_dma_sync_sg_for_cpu) from [<c0327dec>] (__videobuf_s

The current script doesn't expect the symbols to be bound by
parenthesis, and triggers the following errors :

  awk: cmd. line:1: error: Unmatched ( or \(: / (check_sync$/
  [   81.547704] (bucket_find_contain) from (check_sync+0x40/0x4f8)

Fix it by chopping starting and ending parenthesis from the each symbol
name.

As a side note, this probably comes from the function
dump_backtrace_entry(), which is implemented differently for each
architecture.  That makes a single decoding script a bit a challenge.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Michal Marek <mmarek@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-04 16:54:41 -07:00
Sasha Levin
dbd1abb209 decode_stacktrace: make stack dump output useful again
Right now when people try to report issues in the kernel they send stack
dumps to eachother, which looks something like this:

  [    6.906437]  [<ffffffff811f0e90>] ? backtrace_test_irq_callback+0x20/0x20
  [    6.907121]  [<ffffffff84388ce8>] dump_stack+0x52/0x7f
  [    6.907640]  [<ffffffff811f0ec8>] backtrace_regression_test+0x38/0x110
  [    6.908281]  [<ffffffff813596a0>] ? proc_create_data+0xa0/0xd0
  [    6.908870]  [<ffffffff870a8040>] ? proc_modules_init+0x22/0x22
  [    6.909480]  [<ffffffff810020c2>] do_one_initcall+0xc2/0x1e0
  [...]

However, most of the text you get is pure garbage.

The only useful thing above is the function name.  Due to the amount of
different kernel code versions and various configurations being used,
the kernel address and the offset into the function are not really
helpful in determining where the problem actually occured.

Too often the result of someone looking at a stack dump is asking the
person who sent it for a translation for one or more 'addr2line'
translations.  Which slows down the entire process of debugging the
issue (and really annoying).

The decode_stacktrace script is an attempt to make the output more
useful and easy to work with by translating all kernel addresses in the
stack dump into line numbers.  Which means that the stack dump would
look like this:

  [  635.148361]  dump_stack (lib/dump_stack.c:52)
  [  635.149127]  warn_slowpath_common (kernel/panic.c:418)
  [  635.150214]  warn_slowpath_null (kernel/panic.c:453)
  [  635.151031]  _oalloc_pages_slowpath+0x6a/0x7d0
  [  635.152171]  ? zone_watermark_ok (mm/page_alloc.c:1728)
  [  635.152988]  ? get_page_from_freelist (mm/page_alloc.c:1939)
  [  635.154766]  __alloc_pages_nodemask (mm/page_alloc.c:2766)

It's pretty obvious why this is better than the previous stack dump
before.

Usage is pretty simple:

        ./decode_stacktrace.sh [vmlinux] [base path]

Where vmlinux is the vmlinux to extract line numbers from and base path
is the path that points to the root of the build tree, for example:

        ./decode_stacktrace.sh vmlinux /home/sasha/linux/ < input.log > output.log

The stack trace should be piped through it (I, for example, just pipe
the output of the serial console of my KVM test box through it).

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-10 15:29:43 -07:00