linux.git/arch/x86/kernel/dumpstack_32.c, branch v2.6.28

x86, kexec: fix hang on i386 when panic occurs while console_sem is held

2008-10-22T11:59:44+00:00

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 
Signed-off-by: Ingo Molnar

sysfs: crash debugging

2008-10-16T16:24:41+00:00

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 
Cc: Mathieu Desnoyers 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

dumpstack: x86: various small unification steps

2008-10-13T08:33:45+00:00

- 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 
Signed-off-by: Ingo Molnar

dumpstack: i386: make kstack= an early boot-param and add oops=panic

2008-10-13T08:33:44+00:00

- make kstack= and early_param
 - add oops=panic, setting panic_on_oops

Signed-off-by: Alexander van Heukelum 
Signed-off-by: Ingo Molnar

dumpstack: x86: use log_lvl and unify trace formatting

2008-10-13T08:33:43+00:00

- 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 
Signed-off-by: Ingo Molnar

dumptrace: x86: consistently include loglevel, print stack switch

2008-10-13T08:33:42+00:00

- 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 
Signed-off-by: Ingo Molnar

dumpstack: x86: add "end" parameter to valid_stack_ptr and print_context_stack

2008-10-13T08:33:41+00:00

- 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 
Signed-off-by: Ingo Molnar

dumpstack: x86: make printk_address equal

2008-10-13T08:33:40+00:00

- 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 
Signed-off-by: Ingo Molnar

dumpstack: x86: move die_nmi to dumpstack_32.c

2008-10-13T08:33:39+00:00

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 
Signed-off-by: Ingo Molnar

i386: split out dumpstack code from traps_32.c

2008-10-13T08:33:16+00:00

The dumpstack code is logically quite independent from the
hardware traps. Split it out into its own file.

Signed-off-by: Alexander van Heukelum 
Signed-off-by: Ingo Molnar