From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
To: syzbot <syzbot+10007d66ca02b08f0e60@syzkaller.appspotmail.com>,
syzkaller-bugs@googlegroups.com
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
viro@zeniv.linux.org.uk
Subject: Re: INFO: task hung in __get_super
Date: Tue, 19 Jun 2018 20:44:57 +0900 [thread overview]
Message-ID: <a274f8ff-989a-ccb8-3cc1-78fbdec0604a@I-love.SAKURA.ne.jp> (raw)
In-Reply-To: <001a113ed5540f411c0568cc8418@google.com>
This bug report is getting no feedback, but I guess that this bug is in
block or mm or locking layer rather than fs layer.
NMI backtrace for this bug tends to report that sb_bread() from fill_super()
from mount_bdev() is stalling is the cause of keep holding s_umount_key for
more than 120 seconds. What is strange is that NMI backtrace for this bug tends
to point at rcu_read_lock()/pagecache_get_page()/radix_tree_deref_slot()/
rcu_read_unlock() which is expected not to stall.
Since CONFIG_RCU_CPU_STALL_TIMEOUT is set to 120 (and actually +5 due to
CONFIG_PROVE_RCU=y) which is longer than CONFIG_DEFAULT_HUNG_TASK_TIMEOUT,
maybe setting CONFIG_RCU_CPU_STALL_TIMEOUT to smaller values (e.g. 25) can
give us some hints...
next prev parent reply other threads:[~2018-06-19 11:45 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-01 17:08 INFO: task hung in __get_super syzbot
2018-06-19 11:44 ` Tetsuo Handa [this message]
2018-06-19 11:53 ` Dmitry Vyukov
2018-06-19 14:10 ` Tetsuo Handa
2018-06-19 14:15 ` Dmitry Vyukov
2018-06-20 1:15 ` Tetsuo Handa
2019-04-28 18:14 ` syzbot
2019-04-28 18:51 ` Al Viro
2019-04-29 1:38 ` Tetsuo Handa
2019-04-29 5:30 ` Dmitry Vyukov
2019-04-30 2:55 ` Jan Kara
2019-04-30 3:11 ` Al Viro
2019-04-30 13:07 ` Jan Kara
2019-04-30 13:18 ` Al Viro
2019-04-30 15:07 ` Jan Kara
2019-04-30 15:34 ` Tetsuo Handa
2019-05-03 10:29 ` Tetsuo Handa
2019-05-14 5:15 ` Tetsuo Handa
2019-05-15 1:02 ` Tetsuo Handa
2019-05-15 10:21 ` Jan Kara
2019-05-15 11:32 ` Tetsuo Handa
2019-05-15 13:07 ` Jan Kara
2019-05-16 11:48 ` Jan Kara
2019-05-16 12:17 ` Tetsuo Handa
2019-05-16 12:32 ` Jan Kara
2019-05-16 12:50 ` Tetsuo Handa
2019-05-16 12:33 ` syzbot
2019-05-15 11:59 ` syzbot
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