From: Jiri Slaby <jslaby-AlSwsSmVLrQ@public.gmane.org>
To: aris-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org
Cc: Andrew Morton
<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
Linux kernel mailing list
<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org,
containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Jiri Slaby <jirislaby-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Subject: include/linux/cgroup.h:553 suspicious rcu_dereference_check() usage!
Date: Fri, 14 Sep 2012 11:23:22 +0200 [thread overview]
Message-ID: <5052F78A.7010007@suse.cz> (raw)
Hi,
with current -next trees and LDEP enabled, I'm getting:
===============================
[ INFO: suspicious RCU usage. ]
3.6.0-rc5-next-20120913+ #42 Not tainted
-------------------------------
/home/latest/linux/include/linux/cgroup.h:553 suspicious
rcu_dereference_check() usage!
other info that might help us debug this:
rcu_scheduler_active = 1, debug_locks = 0
2 locks held by kdevtmpfs/23:
#0: (sb_writers){.+.+.+}, at: [<ffffffff8116873f>]
mnt_want_write+0x1f/0x50
#1: (&sb->s_type->i_mutex_key#3/1){+.+.+.}, at: [<ffffffff811558af>]
kern_path_create+0x7f/0x170
stack backtrace:
Pid: 23, comm: kdevtmpfs Not tainted 3.6.0-rc5-next-20120913+ #42
Call Trace:
[<ffffffff810c638d>] lockdep_rcu_suspicious+0xfd/0x130
[<ffffffff8121541d>] devcgroup_inode_mknod+0x19d/0x240
[<ffffffff8107bf54>] ? ns_capable+0x44/0x80
[<ffffffff81156b21>] vfs_mknod+0x71/0xf0
[<ffffffff813a8332>] handle_create.isra.2+0x72/0x200
[<ffffffff813a85d4>] devtmpfsd+0x114/0x140
[<ffffffff813a84c0>] ? handle_create.isra.2+0x200/0x200
[<ffffffff81093ad6>] kthread+0xd6/0xe0
[<ffffffff81654f24>] kernel_thread_helper+0x4/0x10
[<ffffffff8165369d>] ? retint_restore_args+0xe/0xe
[<ffffffff81093a00>] ? kthread_create_on_node+0x140/0x140
[<ffffffff81654f20>] ? gs_change+0xb/0xb
It's due to the commit "device_cgroup: convert device_cgroup internally
to policy + exceptions". It removed rcu locks which are needed in
task_devcgroup called in this chain: devcgroup_inode_mknod OR
__devcgroup_inode_permission -> __devcgroup_inode_permission ->
task_devcgroup -> task_subsys_state -> task_subsys_state_check.
regards,
--
js
suse labs
WARNING: multiple messages have this Message-ID (diff)
From: Jiri Slaby <jslaby@suse.cz>
To: aris@redhat.com
Cc: Andrew Morton <akpm@linux-foundation.org>,
Linux kernel mailing list <linux-kernel@vger.kernel.org>,
Tejun Heo <tj@kernel.org>,
lizefan@huawei.com, containers@lists.linux-foundation.org,
cgroups@vger.kernel.org, Jiri Slaby <jirislaby@gmail.com>
Subject: include/linux/cgroup.h:553 suspicious rcu_dereference_check() usage!
Date: Fri, 14 Sep 2012 11:23:22 +0200 [thread overview]
Message-ID: <5052F78A.7010007@suse.cz> (raw)
Hi,
with current -next trees and LDEP enabled, I'm getting:
===============================
[ INFO: suspicious RCU usage. ]
3.6.0-rc5-next-20120913+ #42 Not tainted
-------------------------------
/home/latest/linux/include/linux/cgroup.h:553 suspicious
rcu_dereference_check() usage!
other info that might help us debug this:
rcu_scheduler_active = 1, debug_locks = 0
2 locks held by kdevtmpfs/23:
#0: (sb_writers){.+.+.+}, at: [<ffffffff8116873f>]
mnt_want_write+0x1f/0x50
#1: (&sb->s_type->i_mutex_key#3/1){+.+.+.}, at: [<ffffffff811558af>]
kern_path_create+0x7f/0x170
stack backtrace:
Pid: 23, comm: kdevtmpfs Not tainted 3.6.0-rc5-next-20120913+ #42
Call Trace:
[<ffffffff810c638d>] lockdep_rcu_suspicious+0xfd/0x130
[<ffffffff8121541d>] devcgroup_inode_mknod+0x19d/0x240
[<ffffffff8107bf54>] ? ns_capable+0x44/0x80
[<ffffffff81156b21>] vfs_mknod+0x71/0xf0
[<ffffffff813a8332>] handle_create.isra.2+0x72/0x200
[<ffffffff813a85d4>] devtmpfsd+0x114/0x140
[<ffffffff813a84c0>] ? handle_create.isra.2+0x200/0x200
[<ffffffff81093ad6>] kthread+0xd6/0xe0
[<ffffffff81654f24>] kernel_thread_helper+0x4/0x10
[<ffffffff8165369d>] ? retint_restore_args+0xe/0xe
[<ffffffff81093a00>] ? kthread_create_on_node+0x140/0x140
[<ffffffff81654f20>] ? gs_change+0xb/0xb
It's due to the commit "device_cgroup: convert device_cgroup internally
to policy + exceptions". It removed rcu locks which are needed in
task_devcgroup called in this chain: devcgroup_inode_mknod OR
__devcgroup_inode_permission -> __devcgroup_inode_permission ->
task_devcgroup -> task_subsys_state -> task_subsys_state_check.
regards,
--
js
suse labs
next reply other threads:[~2012-09-14 9:23 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-14 9:23 Jiri Slaby [this message]
2012-09-14 9:23 ` include/linux/cgroup.h:553 suspicious rcu_dereference_check() usage! Jiri Slaby
2012-09-14 9:40 ` [PATCH] cgroup: fix invalid rcu dereference Jiri Slaby
2012-09-14 13:27 ` Aristeu Rozanski
2012-09-14 17:01 ` Tejun Heo
2012-09-17 1:09 ` Li Zefan
-- strict thread matches above, loose matches on Subject: below --
2012-09-14 9:23 include/linux/cgroup.h:553 suspicious rcu_dereference_check() usage! Jiri Slaby
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5052F78A.7010007@suse.cz \
--to=jslaby-alswssmvlrq@public.gmane.org \
--cc=akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org \
--cc=aris-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org \
--cc=cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
--cc=containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org \
--cc=jirislaby-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org \
--cc=linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
--cc=lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org \
--cc=tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.