From e1e23bb0513520035ec934fa3483507cb6648b7c Mon Sep 17 00:00:00 2001 From: David Rientjes Date: Tue, 7 Oct 2008 14:15:11 -0700 Subject: [PATCH] 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 --- arch/x86/kernel/process_64.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 2a8ccb9238b4..b6b508ea7110 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)) -- 2.20.1