From: Tejun Heo <tj@kernel.org>
To: "Richard W.M. Jones" <rjones@redhat.com>
Cc: Josh Boyer <jwboyer@fedoraproject.org>,
Jeff Moyer <jmoyer@redhat.com>,
msnitzer@redhat.com, Li Zefan <lizefan@huawei.com>,
Johannes Weiner <hannes@cmpxchg.org>,
cgroups@vger.kernel.org,
"Linux-Kernel@Vger. Kernel. Org" <linux-kernel@vger.kernel.org>
Subject: Re: __blkg_lookup oops with 4.2-rcX
Date: Sat, 5 Sep 2015 14:38:01 -0400 [thread overview]
Message-ID: <20150905183801.GA8231@mtj.duckdns.org> (raw)
In-Reply-To: <20150905154840.GA19460@redhat.com>
On Sat, Sep 05, 2015 at 04:48:40PM +0100, Richard W.M. Jones wrote:
> On Sat, Sep 05, 2015 at 04:34:39PM +0100, Richard W.M. Jones wrote:
> > [ 52.259269] BUG: unable to handle kernel NULL pointer dereference at 00000000000009c8
> > [ 52.259269] IP: [<ffffffff813f8b10>] __blkg_lookup+0x40/0xe0
>
> And also:
>
> $ addr2line -e /usr/lib/debug/lib/modules/4.3.0-0.rc0.git7.1.rwmj3.fc24.x86_64/vmlinux ffffffff813f8b10
> /usr/src/debug/kernel-4.2.fc24/linux-4.3.0-0.rc0.git7.1.rwmj3.fc24.x86_64/block/blk-cgroup.c:158
>
> 152 /*
> 153 * Hint didn't match. Look up from the radix tree. Note that the
> 154 * hint can only be updated under queue_lock as otherwise @blkg
> 155 * could have already been removed from blkg_tree. The caller is
> 156 * responsible for grabbing queue_lock if @update_hint.
> 157 */
> 158 blkg = radix_tree_lookup(&blkcg->blkg_tree, q->id);
Okay, found the bug. It was an existing problem which got exposed by
the recent bypass change. Will soon post a patch.
Thanks a lot!
--
tejun
next prev parent reply other threads:[~2015-09-05 18:38 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-30 12:30 __blkg_lookup oops with 4.2-rcX Josh Boyer
2015-08-30 18:04 ` Richard W.M. Jones
2015-09-02 14:53 ` Tejun Heo
2015-09-02 15:32 ` Tejun Heo
2015-09-04 10:46 ` Richard W.M. Jones
2015-09-04 17:13 ` Tejun Heo
2015-09-04 18:17 ` Richard W.M. Jones
2015-09-04 20:42 ` Richard W.M. Jones
2015-09-05 15:34 ` Richard W.M. Jones
2015-09-05 15:48 ` Richard W.M. Jones
2015-09-05 18:38 ` Tejun Heo [this message]
2015-09-05 19:47 ` [PATCH block/for-linus] block: blkg_destroy_all() should clear q->root_blkg and ->root_rl.blkg Tejun Heo
2015-09-06 8:30 ` Richard W.M. Jones
2015-09-08 15:31 ` Tejun Heo
2015-09-08 15:35 ` Jens Axboe
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