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ARM64: check stack pointer in get_wchan

Browse source 
get_wchan() is lockless. Task may wakeup at any time and change its own stack,
thus each next stack frame may be overwritten and filled with random stuff.

Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Konstantin Khlebnikov 2013-12-05 13:30:10 +00:00 committed by Catalin Marinas
parent 50afc33a90
commit 408c3658b0
1 changed files with 5 additions and 2 deletions
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7
arch/arm64/kernel/process.c
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@ -308,6 +308,7 @@ struct task_struct *__switch_to(struct task_struct *prev,
unsigned long get_wchan(struct task_struct *p)
{
struct stackframe frame;
unsigned long stack_page;
int count = 0;
if (!p || p == current || p->state == TASK_RUNNING)
return 0;
@ -315,9 +316,11 @@ unsigned long get_wchan(struct task_struct *p)
frame.fp = thread_saved_fp(p);
frame.sp = thread_saved_sp(p);
frame.pc = thread_saved_pc(p);
stack_page = (unsigned long)task_stack_page(p);
do {
int ret = unwind_frame(&frame);
if (ret < 0)
if (frame.sp < stack_page ||
frame.sp >= stack_page + THREAD_SIZE ||
unwind_frame(&frame))
return 0;
if (!in_sched_functions(frame.pc))
return frame.pc;