From: Vladislav Bolkhovitin <vst@vlnb.net>
To: linux-kernel@vger.kernel.org
Subject: 2.6.35: suspicious rcu_dereference_check() usage
Date: Wed, 04 Aug 2010 14:56:00 +0400 [thread overview]
Message-ID: <4C594740.1090608@vlnb.net> (raw)
Hello,
Today I gave a first try to 2.6.35 and it immediately produced:
Aug 4 15:12:09 tgt kernel: [ 183.799040] ===================================================
Aug 4 15:12:09 tgt kernel: [ 183.799158] [ INFO: suspicious rcu_dereference_check() usage. ]
Aug 4 15:12:09 tgt kernel: [ 183.799158] ---------------------------------------------------
Aug 4 15:12:09 tgt kernel: [ 183.799158] kernel/exit.c:1387 invoked rcu_dereference_check() without protection!
Aug 4 15:12:09 tgt kernel: [ 183.799158]
Aug 4 15:12:09 tgt kernel: [ 183.799158] other info that might help us debug this:
Aug 4 15:12:09 tgt kernel: [ 183.799158]
Aug 4 15:12:09 tgt kernel: [ 183.799158]
Aug 4 15:12:09 tgt kernel: [ 183.799158] rcu_scheduler_active = 1, debug_locks = 1
Aug 4 15:12:09 tgt kernel: [ 183.799158] 2 locks held by mc/3751:
Aug 4 15:12:09 tgt kernel: [ 183.799158] #0: (tasklist_lock){.+.+..}, at: [<7813d277>] do_wait+0xa1/0x24f
Aug 4 15:12:09 tgt kernel: [ 183.799158] #1: (&(&sighand->siglock)->rlock){-.....}, at: [<7813c6eb>] wait_consider_task+0xdd/0xbc8
Aug 4 15:12:09 tgt kernel: [ 183.799158]
Aug 4 15:12:09 tgt kernel: [ 183.799158] stack backtrace:
Aug 4 15:12:09 tgt kernel: [ 183.799158] Pid: 3751, comm: mc Not tainted 2.6.35-scst-dbg #3
Aug 4 15:12:09 tgt kernel: [ 183.799158] Call Trace:
Aug 4 15:12:09 tgt kernel: [ 183.799158] [<784660a3>] ? printk+0x2d/0x32
Aug 4 15:12:09 tgt kernel: [ 183.799158] [<78165d6e>] lockdep_rcu_dereference+0x8e/0x96
Aug 4 15:12:09 tgt kernel: [ 183.799158] [<7813caa3>] wait_consider_task+0x495/0xbc8
Aug 4 15:12:09 tgt kernel: [ 183.799158] [<7846c809>] ? sub_preempt_count+0x9/0xad
Aug 4 15:12:09 tgt kernel: [ 183.799158] [<78164056>] ? put_lock_stats+0xd/0x28
Aug 4 15:12:09 tgt kernel: [ 183.799158] [<7813d277>] ? do_wait+0xa1/0x24f
Aug 4 15:12:09 tgt kernel: [ 183.799158] [<78469218>] ? _raw_read_lock+0x6b/0x72
Aug 4 15:12:09 tgt kernel: [ 183.799158] [<7813d2ca>] do_wait+0xf4/0x24f
Aug 4 15:12:09 tgt kernel: [ 183.799158] [<7813d48d>] sys_wait4+0x68/0xb2
Aug 4 15:12:09 tgt kernel: [ 183.799158] [<7813afbd>] ? child_wait_callback+0x0/0x73
Aug 4 15:12:09 tgt kernel: [ 183.799158] [<7813d503>] sys_waitpid+0x2c/0x2e
Aug 4 15:12:09 tgt kernel: [ 183.799158] [<78102d13>] sysenter_do_call+0x12/0x32
I guess, it was just after I started mc.
Vlad
next reply other threads:[~2010-08-04 10:56 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-04 10:56 Vladislav Bolkhovitin [this message]
2010-08-09 14:46 ` 2.6.35: suspicious rcu_dereference_check() usage Maciej Rutecki
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=4C594740.1090608@vlnb.net \
--to=vst@vlnb.net \
--cc=linux-kernel@vger.kernel.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox