lkml.org 
[lkml]   [2010]   [Nov]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] ioprio: rcu_read_lock/unlock protect find_task_by_vpid call (V2)
On 2010-11-09 21:15, Paul E. McKenney wrote:
> On Tue, Nov 09, 2010 at 12:21:24PM +0200, Sergey Senozhatsky wrote:
>> Commit 4221a9918e38b7494cee341dda7b7b4bb8c04bde "Add RCU check for
>> find_task_by_vpid()" introduced rcu_lockdep_assert to find_task_by_pid_ns..
>> Assertion failed in sys_ioprio_get. The patch is fixing assertion
>> failure in ioprio_set as well.
>>
>> kernel/pid.c:419 invoked rcu_dereference_check() without protection!
>>
>> stack backtrace:
>> Pid: 4254, comm: iotop Not tainted
>> Call Trace:
>> [<ffffffff810656f2>] lockdep_rcu_dereference+0xaa/0xb2
>> [<ffffffff81053c67>] find_task_by_pid_ns+0x4f/0x68
>> [<ffffffff81053c9d>] find_task_by_vpid+0x1d/0x1f
>> [<ffffffff811104e2>] sys_ioprio_get+0x50/0x2da
>> [<ffffffff81002182>] system_call_fastpath+0x16/0x1b
>>
>> V2: rcu critical section expanded according to comment by Paul E. McKenne:
>> | Looking over the patch again, the scope of the RCU read-side critical
>> | section needs to expand to cover the use of the pointer as well as the
>> | call to find_task_by_vpid().
>
> Thank you, Sergey!
>
> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
>
> Jens, are you willing to take this one?

Certainly, thanks guys!

--
Jens Axboe



\
 
 \ /
  Last update: 2010-11-09 21:23    [W:1.347 / U:0.044 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site