Commit Graph

18 Commits

Author SHA1 Message Date
Steven Rostedt
7ee991fbc6 ftrace: print real return in dumpstack for function graph
Impact: better dumpstack output

I noticed in my crash dumps and even in the stack tracer that a
lot of functions listed in the stack trace are simply
return_to_handler which is ftrace graphs way to insert its own
call into the return of a function.

But we lose out where the actually function was called from.

This patch adds in hooks to the dumpstack mechanism that detects
this and finds the real function to print. Both are printed to
let the user know that a hook is still in place.

This does give a funny side effect in the stack tracer output:

        Depth   Size      Location    (80 entries)
        -----   ----      --------
  0)     4144      48   save_stack_trace+0x2f/0x4d
  1)     4096     128   ftrace_call+0x5/0x2b
  2)     3968      16   mempool_alloc_slab+0x16/0x18
  3)     3952     384   return_to_handler+0x0/0x73
  4)     3568    -240   stack_trace_call+0x11d/0x209
  5)     3808     144   return_to_handler+0x0/0x73
  6)     3664    -128   mempool_alloc+0x4d/0xfe
  7)     3792     128   return_to_handler+0x0/0x73
  8)     3664     -32   scsi_sg_alloc+0x48/0x4a [scsi_mod]

As you can see, the real functions are now negative. This is due
to them not being found inside the stack.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-03 08:56:25 +01:00
Neil Horman
878719e831 x86: unify appropriate bits from dumpstack_32 and dumpstack_64
Impact: cleanup

As promised, now that dumpstack_32 and dumpstack_64 have so many bits
in common, we should merge the in-sync bits into a common file, to
prevent them from diverging again.

This patch removes bits which are common between dumpstack_32.c and
dumpstack_64.c and places them in a common dumpstack.c which is built
for both 32 and 64 bit arches.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

 Makefile       |    2
 arch/x86/kernel/Makefile       |    2
 arch/x86/kernel/Makefile       |    2
 arch/x86/kernel/Makefile       |    2
 arch/x86/kernel/Makefile       |    2
 arch/x86/kernel/Makefile       |    2
 arch/x86/kernel/dumpstack.c    |  319 +++++++++++++++++++++++++++++++++++++++++
 arch/x86/kernel/dumpstack.h    |   39 +++++
 arch/x86/kernel/dumpstack_32.c |  294 -------------------------------------
 arch/x86/kernel/dumpstack_64.c |  285 ------------------------------------
 5 files changed, 363 insertions(+), 576 deletions(-)
2008-10-27 19:21:19 +01:00
Alexander van Heukelum
871d3779cb i386, dumpstack: unify die()
Make i386's die() equal to x86_64's version.

Whitespace-only changes on x86_64, to make it equal to i386's
version. (user_mode and user_mode_vm are equal on x86_64.)

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-22 14:00:26 +02:00
Alexander van Heukelum
e06ca430c3 i386, dumpstack: use oops_begin/oops_end in die_nmi
Use oops_begin and oops_end in die_nmi.

Whitespace-only changes on x86_64, to make it equal to i386's
version.

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-22 14:00:26 +02:00
Alexander van Heukelum
e4955cfd2f i386, dumpstack: use x86_64's method to account die_nest_count
oops_begin/oops_end should always be used in pairs. On x86_64
oops_begin increments die_nest_count, and oops_end decrements
die_nest_count. Doing this makes oops_begin and oops_end equal
to the x86_64 versions.

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-22 14:00:25 +02:00
Alexander van Heukelum
10b14cb7eb x86, dumpstack: always call oops_exit from oops_end
Always call oops_exit from oops_end, even if signr==0.

Also, move add_taint(TAINT_DIE) from __die to oops_end
on x86_64 and interchange two lines to make oops_end
more similar to the i386-version.

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-22 14:00:24 +02:00
Alexander van Heukelum
874d93d118 x86, dumpstack: let signr=0 signal no do_exit
Change oops_end such that signr=0 signals that do_exit
is not to be called.

Currently, each use of __die is soon followed by a call
to oops_end and 'regs' is set to NULL if oops_end is expected
not to call do_exit. Change all such pairs to set signr=0
instead. On x86_64 oops_end is used 'bare' in die_nmi; use
signr=0 instead of regs=NULL there, too.

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-22 14:00:23 +02:00
Alexander van Heukelum
b4b8f87bf4 i386, dumpstack: move crash_kexec before bust_spinlocks(0) in oops_end
crash_kexec should not be called with console_sem held. Move
the call before bust_spinlocks(0) in oops_end to avoid the
problem.

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Acked-by: "Neil Horman" <nhorman@tuxdriver.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-22 14:00:22 +02:00
Neil Horman
cf52ebedba x86, kexec: fix hang on i386 when panic occurs while console_sem is held
There's a corner case in 32 bit x86 kdump at the moment.  When the box
panics via nmi, we call bust_spinlocks(1) to disable sensitivity to the
console_sem (allowing us to print to the console in all cases), but we don't
call crash_kexec, until after we call bust_spinlocks(0), which re-enables
console_sem sensitivity.

The result is that, if we get an nmi while the console_sem is held and
kdump is configured, and we try to print something to the console during
kdump shutdown (which we often do) we deadlock the box.  The fix is to
simply do what 64 bit die_nmi does which is to not call bust_spinlocks(0)
until after we call crash_kexec.

Patch below tested successfully by me.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-22 13:59:44 +02:00
Andrew Morton
ae87221d3c sysfs: crash debugging
Print the name of the last-accessed sysfs file when we oops, to help track
down oopses which occur in sysfs store/read handlers.  Because these oopses
tend to not leave any trace of the offending code in the stack traces.

Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-10-16 09:24:41 -07:00
Alexander van Heukelum
8a541665b9 dumpstack: x86: various small unification steps
- define STACKSLOTS_PER_LINE and use it
 - define get_bp macro to hide the %%ebp/%%rbp difference
 - i386: check task==NULL in dump_trace, like x86_64
 - i386: show_trace(NULL, ...) uses current automatically
 - x86_64: use [#%d] for die_counter, like i386
 - whitespace and comments

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-13 10:33:45 +02:00
Alexander van Heukelum
802a67de0c dumpstack: i386: make kstack= an early boot-param and add oops=panic
- make kstack= and early_param
 - add oops=panic, setting panic_on_oops

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-13 10:33:44 +02:00
Alexander van Heukelum
ca0a816403 dumpstack: x86: use log_lvl and unify trace formatting
- x86: Write log_lvl strings if available
 - start raw stack dumps on new line
 - i386: Remove extra indentation for raw stack dumps

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-13 10:33:43 +02:00
Alexander van Heukelum
2ac53721f3 dumptrace: x86: consistently include loglevel, print stack switch
- i386 and x86_64: always printk the 'data' parameter
 - i386: announce stack switch (irq -> normal)
 - i386: check if there is a stack switch before announcing it

There is a warning that 'context' might come out corrupt in early
boot. If this is true it should be fixed, not worked around.

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-13 10:33:42 +02:00
Alexander van Heukelum
3a18512db0 dumpstack: x86: add "end" parameter to valid_stack_ptr and print_context_stack
- Add "end" parameter to valid_stack_ptr and print_context_stack
 - use sizeof(long) as the size of a word on the stack

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-13 10:33:41 +02:00
Alexander van Heukelum
161827903b dumpstack: x86: make printk_address equal
- x86_64: use %p to print an address
 - make i386-version the same as the above

The result should be the same on x86_64; on i386 the
output only changes if CONFIG_KALLSYMS is turned off,
in which case the address is printed twice.

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-13 10:33:40 +02:00
Alexander van Heukelum
dd6e4eba1c dumpstack: x86: move die_nmi to dumpstack_32.c
For some reason die_nmi is still defined in traps.c for
i386, but is found in dumpstack_64.c for x86_64. Move it
to dumpstack_32.c

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-13 10:33:39 +02:00
Alexander van Heukelum
2bc5f927d4 i386: split out dumpstack code from traps_32.c
The dumpstack code is logically quite independent from the
hardware traps. Split it out into its own file.

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-13 10:33:16 +02:00