Messages in this thread | | | Date | Tue, 21 Apr 2009 14:15:58 +0530 | From | Balbir Singh <> | Subject | Re: [patch 1/3] mm: fix pageref leak in do_swap_page() |
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* Johannes Weiner <hannes@cmpxchg.org> [2009-04-21 10:19:03]:
> On Tue, Apr 21, 2009 at 08:44:20AM +0530, Balbir Singh wrote: > > * Johannes Weiner <hannes@cmpxchg.org> [2009-04-20 22:24:43]: > > > > > By the time the memory cgroup code is notified about a swapin we > > > already hold a reference on the fault page. > > > > > > If the cgroup callback fails make sure to unlock AND release the page > > > or we leak the reference. > > > > > > Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> > > > Cc: Balbir Singh <balbir@linux.vnet.ibm.com> > > > > Seems reasonable to me, could you make the changelog more verbose and > > mention that lookup_swap_cache() gets a reference to the page and we > > need to release the extra reference. > > Okay, I will add that information. >
Thanks
> > BTW, have you had any luck reproducing the issue? How did you catch > > the problem? > > I reviewed all the exit points when I shuffled code around in there > for another series that uses a lighter version of do_wp_page() for > swap write-faults. I never triggered that problem. >
Good way of catching a problem, play with the code :)
-- Balbir
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