From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: Andrew Morton <akpm@linux-foundation.org>,
Dave Chinner <david@fromorbit.com>
Cc: linux-mm@kvack.org, linux-xfs@vger.kernel.org,
bugzilla-daemon@bugzilla.kernel.org, goodmirek@goodmirek.com,
Hillf Danton <hillf.zj@alibaba-inc.com>,
Dmitry Vyukov <dvyukov@gmail.com>,
Joel Fernandes <joel@joelfernandes.org>,
Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Subject: Re: [Bug 205135] System hang up when memory swapping (kswapd deadlock)
Date: Tue, 22 Oct 2019 18:22:28 -0700 [thread overview]
Message-ID: <20191023012228.GP913374@magnolia> (raw)
In-Reply-To: <20191022152422.e47fda82879dc7cd1f3cf5e5@linux-foundation.org>
On Tue, Oct 22, 2019 at 03:24:22PM -0700, Andrew Morton wrote:
>
> (switched to email. Please respond via emailed reply-to-all, not via the
> bugzilla web interface).
>
> On Tue, 22 Oct 2019 09:02:22 +0000 bugzilla-daemon@bugzilla.kernel.org wrote:
>
> > https://bugzilla.kernel.org/show_bug.cgi?id=205135
> >
> > --- Comment #7 from goodmirek@goodmirek.com ---
> > Everyone who uses a swapfile on XFS filesystem seem affected by this hang up.
> > Not sure about other filesystems, I did not have a chance to test it elsewhere.
> >
> > This unreproduced bot crash could be related:
> > https://lore.kernel.org/linux-mm/20190910071804.2944-1-hdanton@sina.com/
>
> Thanks. Might be core MM, might be XFS, might be Fedora.
>
> Hilf, does your patch look related? That seems to have gone quiet?
>
> Should we progress Tetsuo's patch?
Hmm...
Oct 09 15:44:52 kernel: Linux version 5.4.0-0.rc1.git1.1.fc32.x86_64 (mockbuild@bkernel03.phx2.fedoraproject.org) (gcc version 9.2.1 20190827 (Red Hat 9.2.1-1) (GCC)) #1 SMP Fri Oct 4 14:57:23 UTC 2019
...istr 5.4-rc1 had some writeback bugs in it...
-> #1 (fs_reclaim){+.+.}:
Oct 09 13:47:08 kernel: fs_reclaim_acquire.part.0+0x25/0x30
Oct 09 13:47:08 kernel: __kmalloc+0x4f/0x330
Oct 09 13:47:08 kernel: kmem_alloc+0x83/0x1a0 [xfs]
Oct 09 13:47:08 kernel: kmem_alloc_large+0x3c/0x100 [xfs]
Oct 09 13:47:08 kernel: xfs_attr_copy_value+0x5d/0xa0 [xfs]
Oct 09 13:47:08 kernel: xfs_attr_get+0xe7/0x1d0 [xfs]
Oct 09 13:47:08 kernel: xfs_get_acl+0xad/0x1e0 [xfs]
Oct 09 13:47:08 kernel: get_acl+0x81/0x110
Oct 09 13:47:08 kernel: posix_acl_create+0x58/0x160
Oct 09 13:47:08 kernel: xfs_generic_create+0x7e/0x2f0 [xfs]
Oct 09 13:47:08 kernel: lookup_open+0x5bd/0x820
Oct 09 13:47:08 kernel: path_openat+0x340/0xcb0
Oct 09 13:47:08 kernel: do_filp_open+0x91/0x100
Oct 09 13:47:08 kernel: do_sys_open+0x184/0x220
Oct 09 13:47:08 kernel: do_syscall_64+0x5c/0xa0
Oct 09 13:47:08 kernel: entry_SYSCALL_64_after_hwframe+0x49/0xbe
That's XFS trying to allocate memory to load an acl off disk, only it
looks this thread does a MAYFAIL allocation. It's a GFP_FS (since we
don't set KM_NOFS) allocation so we recurse into fs reclaim, and the
ACL-getter has locked the inode (which is probably why lockdep
triggers). I wonder if that's really a deadlock vs. just super-slow
behavior, but otoh I don't think we're supposed to allow reclaim to jump
into the filesystems when the fs has locks held.
That kmem_alloc_large should probably be changed to KM_NOFS. Dave?
--D
next prev parent reply other threads:[~2019-10-23 1:22 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <bug-205135-27@https.bugzilla.kernel.org/>
[not found] ` <bug-205135-27-vbbrgnF9A3@https.bugzilla.kernel.org/>
2019-10-22 22:24 ` [Bug 205135] System hang up when memory swapping (kswapd deadlock) Andrew Morton
2019-10-23 1:22 ` Darrick J. Wong [this message]
2019-10-23 2:37 ` Su Yue
2019-10-23 6:49 ` Dave Chinner
2019-10-23 7:12 ` Dave Chinner
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