From: Oleg Nesterov <oleg@redhat.com>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Greg Thelen <gthelen@google.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Jens Axboe <jens.axboe@oracle.com>
Subject: Re: INFO: suspicious rcu_dereference_check() usage - kernel/pid.c:419 invoked rcu_dereference_check() without protection!
Date: Wed, 10 Nov 2010 16:55:30 +0100 [thread overview]
Message-ID: <20101110155530.GA1905@redhat.com> (raw)
In-Reply-To: <20101109202900.GV4032@linux.vnet.ibm.com>
On 11/09, Paul E. McKenney wrote:
>
> Thank you, Oleg! Greg, would you be willing to update your patch
> to remove the comment? (Perhaps tasklist_lock as well...)
Agreed, I think tasklock should be killed.
But wait. Whatever we do, isn't this code racy? I do not see why, say,
sys_ioprio_set(IOPRIO_WHO_PROCESS) can't install ->io_context after
this task has already passed exit_io_context().
Jens, am I missed something?
Oleg.
WARNING: multiple messages have this Message-ID (diff)
From: Oleg Nesterov <oleg@redhat.com>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Greg Thelen <gthelen@google.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Jens Axboe <jens.axboe@oracle.com>
Subject: Re: INFO: suspicious rcu_dereference_check() usage - kernel/pid.c:419 invoked rcu_dereference_check() without protection!
Date: Wed, 10 Nov 2010 16:55:30 +0100 [thread overview]
Message-ID: <20101110155530.GA1905@redhat.com> (raw)
In-Reply-To: <20101109202900.GV4032@linux.vnet.ibm.com>
On 11/09, Paul E. McKenney wrote:
>
> Thank you, Oleg! Greg, would you be willing to update your patch
> to remove the comment? (Perhaps tasklist_lock as well...)
Agreed, I think tasklock should be killed.
But wait. Whatever we do, isn't this code racy? I do not see why, say,
sys_ioprio_set(IOPRIO_WHO_PROCESS) can't install ->io_context after
this task has already passed exit_io_context().
Jens, am I missed something?
Oleg.
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next prev parent reply other threads:[~2010-11-10 16:01 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-12 7:08 INFO: suspicious rcu_dereference_check() usage - kernel/pid.c:419 invoked rcu_dereference_check() without protection! Greg Thelen
2010-10-12 7:08 ` Greg Thelen
2010-11-07 18:20 ` Paul E. McKenney
2010-11-07 18:20 ` Paul E. McKenney
2010-11-08 15:15 ` Oleg Nesterov
2010-11-08 15:15 ` Oleg Nesterov
2010-11-09 20:29 ` Paul E. McKenney
2010-11-09 20:29 ` Paul E. McKenney
2010-11-10 15:55 ` Oleg Nesterov [this message]
2010-11-10 15:55 ` Oleg Nesterov
2010-11-10 16:02 ` Oleg Nesterov
2010-11-10 16:02 ` Oleg Nesterov
2010-11-11 11:19 ` Jens Axboe
2010-11-11 11:19 ` Jens Axboe
2010-11-11 12:30 ` Oleg Nesterov
2010-11-11 12:30 ` Oleg Nesterov
2010-11-11 12:39 ` Jens Axboe
2010-11-11 12:39 ` Jens Axboe
2010-11-11 19:45 ` Greg Thelen
2010-11-11 19:45 ` Greg Thelen
2010-11-11 22:00 ` Oleg Nesterov
2010-11-11 22:00 ` Oleg Nesterov
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