From: Davidlohr Bueso <davidlohr@hp.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>,
Linux MM <linux-mm@kvack.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Rik van Riel <riel@redhat.com>,
Michel Lespinasse <walken@google.com>,
Hugh Dickins <hughd@google.com>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
Oleg Nesterov <oleg@redhat.com>
Subject: Re: [BUG] kernel BUG at mm/vmacache.c:85!
Date: Mon, 28 Apr 2014 15:39:14 -0700 [thread overview]
Message-ID: <1398724754.25549.35.camel@buesod1.americas.hpqcorp.net> (raw)
In-Reply-To: <CA+55aFzXAnTzfNL-bfUFnu15=4Z9HNigoo-XyjmwRvAWX_xz0A@mail.gmail.com>
Adding Oleg.
On Mon, 2014-04-28 at 14:55 -0700, Linus Torvalds wrote:
> On Mon, Apr 28, 2014 at 2:20 PM, Linus Torvalds
> <torvalds@linux-foundation.org> wrote:
> >
> > That said, the bug does seem to be that some path doesn't invalidate
> > the vmacache sufficiently, or something inserts a vmacache entry into
> > the current process when looking up a remote process or whatever.
> > Davidlohr, ideas?
>
> Maybe we missed some use_mm() call. That will change the current mm
> without flushing the vma cache. The code considers kernel threads to
> be bad targets for vma caching for this reason (and perhaps others),
> but maybe we missed something.
>
> I wonder if we should just invalidate the vma cache in use_mm(), and
> remote the "kernel tasks are special" check.
>
> Srivatsa, are you doing something peculiar on that system that would
> trigger this? I see some kdump failures in the log, anything else?
Is this perhaps a KVM guest? fwiw I see CONFIG_KVM_ASYNC_PF=y which is a
user of use_mm().
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next prev parent reply other threads:[~2014-04-28 22:39 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-28 19:18 Srivatsa S. Bhat
2014-04-28 19:20 ` Srivatsa S. Bhat
2014-04-28 21:20 ` Linus Torvalds
2014-04-28 21:55 ` Linus Torvalds
2014-04-28 22:05 ` Hugh Dickins
2014-04-28 22:14 ` Davidlohr Bueso
2014-04-28 22:25 ` Linus Torvalds
2014-04-29 9:59 ` Srivatsa S. Bhat
2014-04-30 19:16 ` Srivatsa S. Bhat
2014-04-30 19:18 ` Srivatsa S. Bhat
2014-04-30 19:20 ` Srivatsa S. Bhat
2014-04-30 20:26 ` Linus Torvalds
2014-05-01 3:56 ` Hugh Dickins
2014-04-28 22:39 ` Davidlohr Bueso [this message]
2014-04-28 22:58 ` Linus Torvalds
2014-04-28 23:11 ` Andrew Morton
2014-04-28 23:57 ` Linus Torvalds
2014-04-29 0:11 ` Davidlohr Bueso
2014-04-29 10:02 ` Srivatsa S. Bhat
2014-04-29 12:52 ` [PATCH] vmacache: change vmacache_find() to always check ->vm_mm Oleg Nesterov
2014-04-29 13:09 ` Srivatsa S. Bhat
2014-04-29 14:02 ` Oleg Nesterov
2014-04-29 12:40 ` [BUG] kernel BUG at mm/vmacache.c:85! Oleg Nesterov
2014-04-29 8:02 ` Srivatsa S. Bhat
2014-04-29 7:59 ` Srivatsa S. Bhat
2014-04-29 0:00 ` Dave Jones
2014-04-29 8:21 ` Srivatsa S. Bhat
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