lkml.org 
[lkml]   [2006]   [Aug]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] unserialized task->files changing
Eric Dumazet wrote:
> On Tuesday 08 August 2006 12:12, Christoph Hellwig wrote:
>
>>On Tue, Aug 08, 2006 at 02:07:49PM +0400, Kirill Korotaev wrote:
>>
>>>Fixed race on put_files_struct on exec with proc.
>>>Restoring files on current on error path may lead
>>>to proc having a pointer to already kfree-d files_struct.
>>
>>This is three times the exact same code sequence, it should probably go
>>into a helper:
>>
>>void reset_current_files(struct files_struct *files)
>>{
>> struct files_struct *old = current->files;
>>
>> task_lock(current);
>> current->files = files;
>> task_unlock(current);
>> put_files_struct(old);
>>}
>
>
>
> More over I think you want to task_lock() before reading current->files
> into 'old'
>
> task_lock(current);
> old = current->files;
> current->files = files;
> task_unlock(current);
> put_files_struct(old);
>
> or maybe a xchg() ?

yeah, never do assignments in declarations :)

BTW, not sure about kthread_exit_files() yet, but looks like it suffers too.

unshare_files() changes current->files w/o locking as well. but I can't see
where it puts the old files... hmm...

Kirill
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-08-08 12:47    [W:0.028 / U:0.340 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site