On Tue, Feb 2, 2016 at 10:24 PM, Jiri Kosina [off-list ref] wrote:

On Tue, 2 Feb 2016, Dmitry Vyukov wrote:

quoted

Original log from fuzzer contained the following WARNING in
mm/rmap.c:412. But when I tried to reproduce it, I hit these hanged
processes instead. I can't reliably detect what program triggered
what. So it may be related, or maybe a separate issue.

------------[ cut here ]------------
kernel BUG at mm/rmap.c:412!

Are you by any chance in this test sending signals to the fuzzer?

If so, the bug I just fixed in floppy driver can cause all kinds of memory
corruptions in case you're running multithreaded accessess to /dev/fd0 and
sending singals to the threads that are trying to access /dev/fd0 at the
same time.

Could you please double check that the other floppy fix I've sent you a
couple days ago doesn't fix this as well? (this test makes sense only if
signals are involved though).

I have "floppy: fix lock_fdc() signal handling" applied (the final,
second version).
The process is multithreaded and it can well receive SIGKILLs.

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