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authorDavid Rientjes <rientjes@google.com>2008-10-07 14:15:11 -0700
committerIngo Molnar <mingo@elte.hu>2008-10-12 11:18:59 +0200
commite1e23bb0513520035ec934fa3483507cb6648b7c (patch)
treea05f96cf556599a3a0dbc0de852c57921ae6051f
parentfd048088306656824958e7783ffcee27e241b361 (diff)
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 <rientjes@google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--arch/x86/kernel/process_64.c4
1 files changed, 2 insertions, 2 deletions
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))