From: Mike Snitzer <snitzer@redhat.com>
To: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: device-mapper development <dm-devel@redhat.com>
Subject: Re: [PATCH 2/7] dm: Simplify dm_table_determine_type()
Date: Wed, 16 Nov 2016 18:09:34 -0500 [thread overview]
Message-ID: <20161116230934.GA25435@redhat.com> (raw)
In-Reply-To: <5b14e4ad-3ce3-2deb-f120-946c756b2930@sandisk.com>
On Wed, Nov 16 2016 at 4:53pm -0500,
Bart Van Assche <bart.vanassche@sandisk.com> wrote:
> On 11/16/2016 01:11 PM, Mike Snitzer wrote:
> >On Wed, Nov 16 2016 at 3:14pm -0500,
> >Bart Van Assche <bart.vanassche@sandisk.com> wrote:
> >>After having added WARN_ON_ONCE(sq_count == 0 && mq_count == 0)
> >>close to the end of dm_table_determine_type() the following output
> >>appeared:
> >>
> >>WARNING: CPU: 0 PID: 2458 at drivers/md/dm-table.c:966
> >>dm_table_complete+0x60e/0x6b0 [dm_mod]
> >>[ ... ]
> >>Call Trace:
> >> [<ffffffff81329b45>] dump_stack+0x68/0x93
> >> [<ffffffff810650e6>] __warn+0xc6/0xe0
> >> [<ffffffff810651b8>] warn_slowpath_null+0x18/0x20
> >> [<ffffffffa0021c8e>] dm_table_complete+0x60e/0x6b0 [dm_mod]
> >> [<ffffffffa00245cd>] table_load+0x13d/0x330 [dm_mod]
> >> [<ffffffffa0024490>] ? retrieve_status+0x1b0/0x1b0 [dm_mod]
> >> [<ffffffffa0025145>] ctl_ioctl+0x1f5/0x520 [dm_mod]
> >> [<ffffffffa002547e>] dm_ctl_ioctl+0xe/0x20 [dm_mod]
> >> [<ffffffff811f26cf>] do_vfs_ioctl+0x8f/0x6b0
> >> [<ffffffff811ff41c>] ? __fget+0x10c/0x200
> >> [<ffffffff811ff310>] ? expand_files+0x2a0/0x2a0
> >> [<ffffffff811f2d2c>] SyS_ioctl+0x3c/0x70
> >> [<ffffffff8163f9aa>] entry_SYSCALL_64_fastpath+0x18/0xad
> >>
> >>Is it intentional that dm_table_determine_type() can get called for
> >>a dm device with an empty table?
> >
> >What table were you trying to load when this occurred?
> >
> >Targets like the 'error' target don't have any devices.
>
> Hello Mike,
>
> This was the result of a table load issued by multipathd. Do you
> want me to add more debug code such that the details of the table
> load request are logged?
No, I think it's fine. You likely have 'queue_if_no_path' configured
and multipathd is loading a 'multipath' table that doesn't have any
paths.
next prev parent reply other threads:[~2016-11-16 23:09 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-15 23:31 [PATCH 0/7] dm-mpath: Fix a race condition in the blk-mq path Bart Van Assche
2016-11-15 23:32 ` [PATCH 1/7] dm: Fix a (theoretical?) race condition in rq_completed() Bart Van Assche
2016-11-16 0:46 ` Mike Snitzer
2016-11-15 23:33 ` [PATCH 2/7] dm: Simplify dm_table_determine_type() Bart Van Assche
2016-11-16 14:54 ` Mike Snitzer
2016-11-16 20:14 ` Bart Van Assche
2016-11-16 21:11 ` Mike Snitzer
2016-11-16 21:53 ` Bart Van Assche
2016-11-16 23:09 ` Mike Snitzer [this message]
2016-11-15 23:33 ` [PATCH 3/7] dm-mpath: Document a locking assumption Bart Van Assche
2016-11-18 0:07 ` Mike Snitzer
2016-11-15 23:34 ` [PATCH 4/7] dm-mpath: Change return type of pg_init_all_paths() from int into void Bart Van Assche
2016-11-15 23:34 ` [PATCH 5/7] dm-mpath: Do not touch *__clone if request allocation fails Bart Van Assche
2016-11-15 23:34 ` [PATCH 6/7] dm-mpath: Avoid code duplication in __multipath_map() Bart Van Assche
2016-11-16 0:39 ` Mike Snitzer
2016-11-15 23:35 ` [PATCH 7/7] dm-mpath: Fix a race condition " Bart Van Assche
2016-11-16 0:37 ` Mike Snitzer
2016-11-16 0:40 ` Bart Van Assche
2016-11-16 1:01 ` Mike Snitzer
2016-11-16 1:08 ` Bart Van Assche
2016-11-16 1:50 ` Mike Snitzer
2016-11-21 21:44 ` Bart Van Assche
2016-11-21 23:43 ` Mike Snitzer
2016-11-21 23:57 ` Bart Van Assche
2016-11-22 0:34 ` Mike Snitzer
2016-11-22 23:47 ` Bart Van Assche
2016-11-23 0:48 ` Mike Snitzer
2016-11-23 3:16 ` Mike Snitzer
2016-11-23 18:28 ` Bart Van Assche
2016-11-23 18:50 ` Mike Snitzer
2016-11-16 0:47 ` [PATCH 0/7] dm-mpath: Fix a race condition in the blk-mq path Mike Snitzer
2016-11-16 0:57 ` Bart Van Assche
2016-11-16 1:08 ` Mike Snitzer
2016-11-16 1:10 ` Bart Van Assche
2016-11-16 1:53 ` Mike Snitzer
2016-11-16 7:39 ` Hannes Reinecke
2016-11-16 14:56 ` Mike Snitzer
2016-11-16 18:22 ` Bart Van Assche
2016-11-16 19:32 ` Mike Snitzer
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