Re: perf_fuzzer: BUG in kfree() in ftrace_graph_exit_task

[Thomas Gleixner]

On Mon, 31 Mar 2014, Vince Weaver wrote:
> 
> This turned up with the perf_fuzzer, haswell, 3.14.
> 
> I'm not sure if this is related to the other object corruption bug I am 
> seeing.  The sympstoms are similar (BUG when dereferencing low invalid
> kernel address) but this time the hrtimer code is not involved at all.
> 
> This isn't reproducible, that is if I re-run the fuzzer with the same 
> random seed after reboot the bug doesn't trigger.
> 
> 
> [ 5498.573458] BUG: unable to handle kernel NULL pointer dereference at 000000000000006c
> [ 5498.585181] IP: [<ffffffff81189111>] kfree+0x91/0x220
> [ 5498.593887] PGD 0 
> [ 5498.599365] Oops: 0000 [#1] SMP 
> [ 5498.606127] Dumping ftrace buffer:
> [ 5498.612973]    (ftrace buffer empty)
> [ 5498.619868] Modules linked in: nfsd auth_rpcgss  .....
> [ 5498.720303] CPU: 1 PID: 13 Comm: ksoftirqd/1 Tainted: G        W    3.14.0+ #14

It's already tainted with W, so there was a warning before that
crash. It would be interesting to see that as well.

Thanks,

	tglx


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