Re: fs: NULL deref in atime_needs_update

From: Dmitry Vyukov
Date: Fri Feb 26 2016 - 16:25:49 EST

On Fri, Feb 26, 2016 at 10:21 PM, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote:
> On Thu, Feb 25, 2016 at 04:39:27PM +0000, Al Viro wrote:
>> Hrm... OK, seeing that you still seem to trigger those within an hour or
>> two (and *any* of remaining WARN_ON() are serious bugs - none of the
>> "mitigation had been triggered" remained, sorry for not making it clear),
>> let's try this. Again, any WARN_ON triggered means that we'd caught something,
>> whether it progresses into oops or not.
> Any news on that one? I'm going to carve fixes for understood bugs out of
> that one and put those into tonight push, but it would be nice to sort out
> all remaining crap lurking in that area...
> Another question: what about the very first trace you'd posted, with apparent
> GPF at 00000050? Have you seen anything like that afterwards?

No, I did not have time to retest.

GPF at 00000050 was not mine, it was MickaÃl's.

I did not try to reproduce mine first. But most likely it is the same
as the one I reproduced lately (GPF at NULL in atime_needs_update).