Re: kmemcheck caught read from freed memory (cfq_free_io_context)

From: Paul E. McKenney
Date: Wed Apr 02 2008 - 11:33:58 EST


On Wed, Apr 02, 2008 at 03:41:23PM +0200, Jens Axboe wrote:
> On Wed, Apr 02 2008, Paul E. McKenney wrote:
> > On Wed, Apr 02, 2008 at 02:58:19PM +0200, Jens Axboe wrote:
> > > On Wed, Apr 02 2008, Fabio Checconi wrote:
> > > > > From: Jens Axboe <jens.axboe@xxxxxxxxxx>
> > > > > Date: Wed, Apr 02, 2008 02:36:39PM +0200
> > > > >
> > > > > > Looks good and tests fine as well. I've applied it, on top of the
> > > > > > hlist_for_each_entry_safe_rcu() fix.
> > > > > >
> > > > > > http://git.kernel.dk/?p=linux-2.6-block.git;a=commit;h=436151ad32b4a59e0d36165a7d6312545f126661
> > > > > >
> > > >
> > > > ok, thanks. anyway I don't think the hlist_for_each_entry_safe_rcu()
> > > > is needed at this point, since the pos->next pointer is still valid
> > > > (at least) until the next rcu_read_unlock(). am I wrong?
> > >
> > > it isn't, but it's still clearer. so either that or a nice comment, I
> > > just stuck with what I had already committed.
> >
> > Given Peter's comment, would you be willing to drop the
> > hlist_for_each_entry_safe_rcu()? People tend to read too much into
> > the "safe" sometimes. ;-)
>
> Sure, let me rebase it... I already sent a pull request to Linus, and he
> just loves when I rebase and change the diffstats behind his back :)

Would it help if I submitted the patch to you to back it out later? ;-)

Thanx, Paul
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