From: David Rientjes Date: Sun, 26 Oct 2008 22:13:59 +0000 (-0400) Subject: x86: avoid dereferencing beyond stack + THREAD_SIZE X-Git-Tag: v2.6.27.5~18 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=df211d2ac9df176d9b9b4b0984f9dcb50ece39fc;p=thirdparty%2Fkernel%2Fstable.git x86: avoid dereferencing beyond stack + THREAD_SIZE commit e1e23bb0513520035ec934fa3483507cb6648b7c upstream 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 Cc: Chuck Ebbert Signed-off-by: Greg Kroah-Hartman --- diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index e12e0e4dd2566..5a7c539226619 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -729,12 +729,12 @@ 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))