Re: mm: uninterruptable tasks hanged on mmap_sem

[Jiri Kosina]

On Tue, 2 Feb 2016, Dmitry Vyukov wrote:

> 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).

Thanks,

-- 
Jiri Kosina
SUSE Labs