From: Olga Kornievskaia <aglo@umich.edu>
To: Matthew Wilcox <willy@infradead.org>
Cc: linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: is this hang in a rename syscall is known?
Date: Thu, 9 Apr 2020 15:30:02 -0400 [thread overview]
Message-ID: <CAN-5tyE1NGOf_v+HrTdDTYkHeAwUnYpeK0_LDtPMMHpGrCe-5Q@mail.gmail.com> (raw)
In-Reply-To: <20200409185132.GY21484@bombadil.infradead.org>
On Thu, Apr 9, 2020 at 2:51 PM Matthew Wilcox <willy@infradead.org> wrote:
>
> On Thu, Apr 09, 2020 at 12:44:25PM -0400, Olga Kornievskaia wrote:
> > Hi folks,
> >
> > Getting this hang on a 5.5 kernel, is this a known issue? Thank you.
>
> I haven't seen it reported.
>
> > Apr 7 13:34:53 scspr1865142002 kernel: Not tainted 5.5.7 #1
> > Apr 7 13:34:53 scspr1865142002 kernel: "echo 0 >
> > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> > Apr 7 13:34:53 scspr1865142002 kernel: dt D 0 24788
> > 24323 0x00000080
> > Apr 7 13:34:53 scspr1865142002 kernel: Call Trace:
> > Apr 7 13:34:53 scspr1865142002 kernel: ? __schedule+0x2ca/0x6e0
> > Apr 7 13:34:53 scspr1865142002 kernel: schedule+0x4a/0xb0
> > Apr 7 13:34:53 scspr1865142002 kernel: schedule_preempt_disabled+0xa/0x10
> > Apr 7 13:34:53 scspr1865142002 kernel: __mutex_lock.isra.11+0x233/0x4e0
> > Apr 7 13:34:53 scspr1865142002 kernel: ? strncpy_from_user+0x47/0x160
> > Apr 7 13:34:53 scspr1865142002 kernel: lock_rename+0x28/0xd0
>
> This task is doing a cross-directory rename() operation. We only allow
> one of those in progress per filesystem at any given time (because they're
> quite rare and rearranging the tree like that plays merry havoc with the
> locking, which you need to prevent a directory becoming its own ancestor).
>
> So the question is, who else is in the middle of a rename operation and
> has blocked for a long time while holding the s_vfs_rename_mutex?
>
> As I recall, you work on NFS, so has something weird been going on with
> your network?
Yes indeed the renames were on NFS. I'll take a look at the network
trace (it didn't look like there was an unanswered renamed that would
have been holding a VFS lock). Thanks for reply so far.
prev parent reply other threads:[~2020-04-09 19:30 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-09 16:44 is this hang in a rename syscall is known? Olga Kornievskaia
2020-04-09 18:51 ` Matthew Wilcox
2020-04-09 19:30 ` Olga Kornievskaia [this message]
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