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Commit 75e9de18 authored by Christian Borntraeger's avatar Christian Borntraeger Committed by Martin Schwidefsky
Browse files

[S390] stacktrace bug. 



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: default avatarChristian Borntraeger <cborntra@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 12975aef

arch/s390/kernel/stacktrace.c

+8 −9
Original line number Diff line number Diff line
@@ -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)

{

	register unsigned long sp asm ("15");

	unsigned long orig_sp;

	unsigned long orig_sp, new_sp;



	sp &= PSW_ADDR_INSN;

	orig_sp = sp;

	orig_sp = sp & PSW_ADDR_INSN;



	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);

	if ((sp != orig_sp) && !trace->all_contexts)

	if ((new_sp != orig_sp) && !trace->all_contexts)

		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);

	if ((sp != orig_sp) && !trace->all_contexts)

	if ((new_sp != orig_sp) && !trace->all_contexts)

		return;

	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) + THREAD_SIZE);

	else

		save_context_stack(trace, &trace->skip, sp,

		save_context_stack(trace, &trace->skip, new_sp,

				   S390_lowcore.thread_info,

				   S390_lowcore.thread_info + THREAD_SIZE);

	return;