Re: perf: use after free in perf_remove_from_context

[Sasha Levin]

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On 05/14/2014 12:29 PM, Peter Zijlstra wrote:
> On Mon, May 12, 2014 at 11:42:33AM -0400, Sasha Levin wrote:
>> Hi all,
>> 
>> While fuzzing with trinity inside a KVM tools guest running the latest -next kernel I've stumbled on the following spew. Maybe related to the very recent change in freeing on task exit?
>> 
>> [ 2509.827261] general protection fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC [ 2509.830379] Dumping ftrace buffer: [ 2509.830379]    (ftrace buffer empty) [ 2509.830379] Modules linked in: [ 2509.830379] CPU: 47 PID: 43306 Comm: trinity-c126 Tainted: G        W     3.15.0-rc5-next-20140512-sasha-00019-ga20bc00-dirty #456
> 
> Any particular trinity setup? And would you happen to have the seed of that run?

Nothing special about trinity options. 400 threads and blacklisting some of the
destructive syscalls (umount, reboot, etc).

I don't have the seed, but that problem did reproduce again tonight so I can test
out debug code if you have something in mind.


Thanks,
Sasha

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