From 75e9de18f079a51fa987ef0703112d5bc125fdb7 Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Wed, 11 Oct 2006 15:31:52 +0200 Subject: [PATCH] [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: Christian Borntraeger Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/stacktrace.c | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-) diff --git a/arch/s390/kernel/stacktrace.c b/arch/s390/kernel/stacktrace.c index d9428a0fc8fb..0d14a4789bf2 100644 --- a/arch/s390/kernel/stacktrace.c +++ b/arch/s390/kernel/stacktrace.c @@ -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; -- 2.39.2