From: valdis.kletnieks@vt.edu
To: "Theodore Y. Ts'o" <tytso@mit.edu>,
Dennis Zhou <dennisszhou@gmail.com>, Jens Axboe <axboe@kernel.dk>,
Tejun Heo <tj@kernel.org>
Cc: linux-kernel@vger.kernel.org, linux-block@vger.kernel.org
Subject: Re: [BUG] ext4/block null pointer crashes in linux-next
Date: Tue, 16 Oct 2018 12:12:13 -0400 [thread overview]
Message-ID: <12638.1539706333@turing-police.cc.vt.edu> (raw)
In-Reply-To: <66480.1539693734@turing-police.cc.vt.edu>
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On Tue, 16 Oct 2018 08:42:14 -0400, valdis.kletnieks@vt.edu said:
> [~] zgrep CGROUP /proc/config.gz
> CONFIG_CGROUPS=y
> CONFIG_BLK_CGROUP=y
> # CONFIG_DEBUG_BLK_CGROUP is not set
> (...)
> Looks like I should enable DEBUG_BLK_CGROUP and see what that says.
Built next-20181016 with that enabled - and the exact same kablam.
Started looking at the code, and I noticed that if the .config has
CONFIG_IOSCHED_CFQ=y
# CONFIG_CFQ_GROUP_IOSCHED is not set
CONFIG_BLK_CGROUP=y
then the 'struct cfqg_stats' at line 185 of block/cfq-iosched.c ends up being
zero length (which hints that combo of config variables is a pathological
case). I haven't delved through all the #ifdef'ery, but I wonder if there
may be other corner-case issues with that combo....
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next prev parent reply other threads:[~2018-10-16 16:12 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-15 23:28 [BUG] ext4/block null pointer crashes in linux-next valdis.kletnieks
2018-10-16 1:52 ` Theodore Y. Ts'o
2018-10-16 12:42 ` valdis.kletnieks
2018-10-16 16:12 ` valdis.kletnieks [this message]
2018-10-16 16:02 ` Dennis Zhou
2018-10-16 18:25 ` Dennis Zhou
2018-10-17 15:47 ` valdis.kletnieks
2018-10-17 21:20 ` Dennis Zhou
2018-10-19 15:52 ` valdis.kletnieks
2018-10-19 22:21 ` Dennis Zhou
2018-10-20 2:47 ` valdis.kletnieks
2018-10-20 4:04 ` Dennis Zhou
2018-10-19 23:50 ` valdis.kletnieks
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