Re: [PATCH] epoll: clear the tfile_check_list on -ELOOP

From: Alexandra N. Kossovsky
Date: Wed Apr 18 2012 - 00:56:30 EST

On Tue, Apr 17, 2012 at 02:13:15PM -0700, Andrew Morton wrote:
> On Tue, 17 Apr 2012 10:34:52 -0400
> Jason Baron <jbaron@xxxxxxxxxx> wrote:
> > An epoll_ctl(,EPOLL_CTL_ADD,,) operation can return '-ELOOP' to prevent
> > circular epoll dependencies from being created. However, in that case
> > we do not properly clear the 'tfile_check_list'. Thus, add a call to
> > clear_tfile_check_list() for the -ELOOP case.
> So here I am wondering what effect this bug has upon our users, so I
> can decide which kernel versions should be fixed. Jason didn't tell me
> so I went to read the description of clear_tfile_check_list(). After a
> brief chuckle, I stopped.
> I then found Yurij's original report, so I know what's going on. But I
> still can't write your changelog because I don't know whether this is a
> regression and if it is, which patch caused the regression.

It is a regression, somewhere between 3.2.6 and 3.2.9.
Yurij and me blame
commit 203aa5260edca2ab1872ad8b08386d874f7132f3
Author: Jason Baron <jbaron@xxxxxxxxxx>
Date: Thu Jan 12 17:17:43 2012 -0800
but we have not tested it.

Alexandra N. Kossovsky
OKTET Labs (
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