From: ebiederm@xmission.com (Eric W. Biederman)
To: Fengguang Wu <fengguang.wu@intel.com>
Cc: Serge Hallyn <serge.hallyn@canonical.com>, linux-kernel@vger.kernel.org
Subject: Re: suspicious RCU usage in copy_namespaces()
Date: Sat, 11 Aug 2012 11:02:28 -0700 [thread overview]
Message-ID: <87ehnd1f4b.fsf@xmission.com> (raw)
In-Reply-To: <20120811091920.GA8117@localhost> (Fengguang Wu's message of "Sat, 11 Aug 2012 17:19:20 +0800")
Fengguang Wu <fengguang.wu@intel.com> writes:
> Hi Eric,
>
> The below warning shows up since commit
Thanks. I am believe the usage is actually correct but I will dig some
more and see what it takes to convince the tools of that.
Eric
>
> tree: git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace.git userns-always-map-user-v45
> head: 38a0b1b84f5f613ff4e01fffda27f87d4cb2b649
> commit: 928ccdb582292cec4552bbf5831f7d374ff60269 userns: Allow unprivileged users to create new namespaces
>
> [ 0.053560] ===============================
> [ 0.054000] [ INFO: suspicious RCU usage. ]
> [ 0.055001] 3.6.0-rc1-00116-g48de0c9 #176 Not tainted
> [ 0.055999] -------------------------------
> [ 0.057001] /c/kernel-tests/src/linux/kernel/nsproxy.c:126 suspicious rcu_dereference_check() usage!
> [ 0.057999]
> [ 0.057999] other info that might help us debug this:
> [ 0.057999]
> [ 0.058999]
> [ 0.058999] rcu_scheduler_active = 1, debug_locks = 1
> [ 0.059998] no locks held by swapper/0.
> [ 0.060998]
> [ 0.060998] stack backtrace:
> [ 0.061999] Pid: 0, comm: swapper Not tainted 3.6.0-rc1-00116-g48de0c9 #176
> [ 0.062999] Call Trace:
> [ 0.063532] [<b1047586>] lockdep_rcu_suspicious+0xba/0xc3
> [ 0.064004] [<b103218e>] copy_namespaces+0x59/0x1fd
> [ 0.066002] [<b101792b>] copy_process.part.49+0xec6/0xf02
> [ 0.067002] [<b1011f51>] ? kvm_clock_read+0x18/0x26
> [ 0.068004] [<b1488949>] ? start_kernel+0x304/0x304
> [ 0.069000] [<b1017a49>] do_fork+0xc6/0x23d
> [ 0.070000] [<b104698b>] ? trace_hardirqs_off+0xb/0xd
> [ 0.071001] [<b1037fc0>] ? local_clock+0x36/0x4e
> [ 0.072003] [<b120ab99>] ? _raw_spin_unlock_irqrestore+0x39/0x4f
> [ 0.073053] [<b1488949>] ? start_kernel+0x304/0x304
> [ 0.074002] [<b1006826>] kernel_thread+0x72/0x7a
> [ 0.074999] [<b1488949>] ? start_kernel+0x304/0x304
> [ 0.076001] [<b120fc5c>] ? common_interrupt+0x3c/0x3c
> [ 0.077000] [<b11fc816>] rest_init+0x1a/0x112
> [ 0.077999] [<b1488944>] start_kernel+0x2ff/0x304
> [ 0.079000] [<b14882c2>] i386_start_kernel+0x78/0x7d
> [ 0.080376] Performance Events: unsupported Netburst CPU model 6 no PMU driver, software events only.
> [ 0.086440] device: 'platform': device_add
>
> Thanks,
> Fengguang
prev parent reply other threads:[~2012-08-11 18:02 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-11 9:19 suspicious RCU usage in copy_namespaces() Fengguang Wu
2012-08-11 18:02 ` Eric W. Biederman [this message]
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=87ehnd1f4b.fsf@xmission.com \
--to=ebiederm@xmission.com \
--cc=fengguang.wu@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=serge.hallyn@canonical.com \
/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.