From: David Rientjes Date: Tue, 7 Oct 2008 21:15:11 +0000 (-0700) Subject: x86: avoid dereferencing beyond stack + THREAD_SIZE X-Git-Tag: v2.6.28-rc1~703^2~2 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=e1e23bb0513520035ec934fa3483507cb6648b7c;p=linux-2.6-omap-h63xx.git x86: avoid dereferencing beyond stack + THREAD_SIZE It's possible for get_wchan() to dereference past task->stack + THREAD_SIZE while iterating through instruction pointers if fp equals the upper boundary, causing a kernel panic. Signed-off-by: David Rientjes Signed-off-by: Ingo Molnar --- diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 2a8ccb9238b..b6b508ea711 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -754,12 +754,12 @@ unsigned long get_wchan(struct task_struct *p) if (!p || p == current || p->state == TASK_RUNNING) return 0; stack = (unsigned long)task_stack_page(p); - if (p->thread.sp < stack || p->thread.sp > stack+THREAD_SIZE) + if (p->thread.sp < stack || p->thread.sp >= stack+THREAD_SIZE) return 0; fp = *(u64 *)(p->thread.sp); do { if (fp < (unsigned long)stack || - fp > (unsigned long)stack+THREAD_SIZE) + fp >= (unsigned long)stack+THREAD_SIZE) return 0; ip = *(u64 *)(fp+8); if (!in_sched_functions(ip))