diff options
author | Jesper Juhl <jj@chaosbits.net> | 2011-01-24 22:41:11 +0100 |
---|---|---|
committer | H. Peter Anvin <hpa@linux.intel.com> | 2011-01-24 13:46:15 -0800 |
commit | 2e5aa6824d9e0248d734573dad8858a2cc279cfe (patch) | |
tree | 535b372f88eee1ac3e56eda16c8618499f34fbaa /arch/x86 | |
parent | ec30f343d61391ab23705e50a525da1d55395780 (diff) |
x86-64: Don't use pointer to out-of-scope variable in dump_trace()
In arch/x86/kernel/dumpstack_64.c::dump_trace() we have this code:
...
if (!stack) {
unsigned long dummy;
stack = &dummy;
if (task && task != current)
stack = (unsigned long *)task->thread.sp;
}
bp = stack_frame(task, regs);
/*
* Print function call entries in all stacks, starting at the
* current stack address. If the stacks consist of nested
* exceptions
*/
tinfo = task_thread_info(task);
for (;;) {
char *id;
unsigned long *estack_end;
estack_end = in_exception_stack(cpu, (unsigned long)stack,
&used, &id);
...
You'll notice that we assign to 'stack' the address of the variable
'dummy' which is only in-scope inside the 'if (!stack)'. So when we later
access stack (at the end of the above, and assuming we did not take the
'if (task && task != current)' branch) we'll be using the address of a
variable that is no longer in scope. I believe this patch is the proper
fix, but I freely admit that I'm not 100% certain.
Signed-off-by: Jesper Juhl <jj@chaosbits.net>
LKML-Reference: <alpine.LNX.2.00.1101242232590.10252@swampdragon.chaosbits.net>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'arch/x86')
-rw-r--r-- | arch/x86/kernel/dumpstack_64.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c index 64101335de19..a6b6fcf7f0ae 100644 --- a/arch/x86/kernel/dumpstack_64.c +++ b/arch/x86/kernel/dumpstack_64.c @@ -149,13 +149,13 @@ void dump_trace(struct task_struct *task, unsigned used = 0; struct thread_info *tinfo; int graph = 0; + unsigned long dummy; unsigned long bp; if (!task) task = current; if (!stack) { - unsigned long dummy; stack = &dummy; if (task && task != current) stack = (unsigned long *)task->thread.sp; |