From: David Rientjes Date: Mon, 13 Oct 2008 23:42:12 +0000 (-0400) Subject: x86: avoid dereferencing beyond stack + THREAD_SIZE X-Git-Tag: v2.6.26.7~7 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=76d8cb9a1e102231935e586e888b10ea6ca41101;p=thirdparty%2Fkernel%2Fstable.git x86: avoid dereferencing beyond stack + THREAD_SIZE commit 60e6258cd43f9b06884f04f0f7cefb9c40f17a32 upstream 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 c6eb5c91e5f60..a803de31600e2 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -740,12 +740,12 @@ 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))