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[S390] stacktrace bug.

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The latest kernel 2.6.19-rc1 triggers a bug in the s390 specific stack
trace code when compiled with gcc 3.4.
This patch fixes the latest lock dependency validator code (2.6.19-rc1)
on s390 gcc 3.4. The variable sp was fixed to r15 (which is the stack
pointer in the s390 abi) and assigned new values to r15. Therefore,
gcc 3.4 assigns a new value to r15 and does not restore it on exit (r15
is supposed to be call save) - the kernel stack is broken. Avoid trouble
by not assigning any new value to sp (r15).

Signed-off-by: Christian Borntraeger <cborntra@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Christian Borntraeger 2006-10-11 15:31:52 +02:00 committed by Martin Schwidefsky
parent 12975aef62
commit 75e9de18f0
1 changed files with 8 additions and 9 deletions
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17
arch/s390/kernel/stacktrace.c
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@ -62,27 +62,26 @@ static inline unsigned long save_context_stack(struct stack_trace *trace,
void save_stack_trace(struct stack_trace *trace, struct task_struct *task) void save_stack_trace(struct stack_trace *trace, struct task_struct *task)
{ {
register unsigned long sp asm ("15"); register unsigned long sp asm ("15");
unsigned long orig_sp; unsigned long orig_sp, new_sp;
sp &= PSW_ADDR_INSN; orig_sp = sp & PSW_ADDR_INSN;
orig_sp = sp;
sp = save_context_stack(trace, &trace->skip, sp, new_sp = save_context_stack(trace, &trace->skip, orig_sp,
S390_lowcore.panic_stack - PAGE_SIZE, S390_lowcore.panic_stack - PAGE_SIZE,
S390_lowcore.panic_stack); S390_lowcore.panic_stack);
if ((sp != orig_sp) && !trace->all_contexts) if ((new_sp != orig_sp) && !trace->all_contexts)
return; return;
sp = save_context_stack(trace, &trace->skip, sp, new_sp = save_context_stack(trace, &trace->skip, new_sp,
S390_lowcore.async_stack - ASYNC_SIZE, S390_lowcore.async_stack - ASYNC_SIZE,
S390_lowcore.async_stack); S390_lowcore.async_stack);
if ((sp != orig_sp) && !trace->all_contexts) if ((new_sp != orig_sp) && !trace->all_contexts)
return; return;
if (task) if (task)
save_context_stack(trace, &trace->skip, sp, save_context_stack(trace, &trace->skip, new_sp,
(unsigned long) task_stack_page(task), (unsigned long) task_stack_page(task),
(unsigned long) task_stack_page(task) + THREAD_SIZE); (unsigned long) task_stack_page(task) + THREAD_SIZE);
else else
save_context_stack(trace, &trace->skip, sp, save_context_stack(trace, &trace->skip, new_sp,
S390_lowcore.thread_info, S390_lowcore.thread_info,
S390_lowcore.thread_info + THREAD_SIZE); S390_lowcore.thread_info + THREAD_SIZE);
return; return;