From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org (Eric W. Biederman) Subject: Re: [PATCHv3] inotify: Convert to using per-namespace limits Date: Thu, 15 Dec 2016 11:29:06 +1300 Message-ID: <87eg1a2lhp.fsf@xmission.com> References: <87oa0fpsqs.fsf@xmission.com> <1481723793-6756-1-git-send-email-n.borisov.lkml@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1481723793-6756-1-git-send-email-n.borisov.lkml-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> (Nikolay Borisov's message of "Wed, 14 Dec 2016 15:56:33 +0200") List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Nikolay Borisov Cc: containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, avagin-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org, serge-A9i7LUbDfNHQT0dZR+AlfA@public.gmane.org List-Id: containers.vger.kernel.org Nikolay Borisov writes: > This patchset converts inotify to using the newly introduced > per-userns sysctl infrastructure. > > Currently the inotify instances/watches are being accounted in the > user_struct structure. This means that in setups where multiple > users in unprivileged containers map to the same underlying > real user (i.e. pointing to the same user_struct) the inotify limits > are going to be shared as well, allowing one user(or application) to exhaust > all others limits. > > Fix this by switching the inotify sysctls to using the > per-namespace/per-user limits. This will allow the server admin to > set sensible global limits, which can further be tuned inside every > individual user namespace. Additionally, in order to preserve the > sysctl ABI make the existing inotify instances/watches sysctls > modify the values of the initial user namespace. > > Signed-off-by: Nikolay Borisov > Acked-by: Jan Kara > Acked-by: Serge Hallyn > --- > > Okay, so here is another version, which should > hopefully be free of slab corruptions. There was an issue > where in ucount.c the ifdef was checking the CONFIG_INOTIFY_USER_ > (pay attention to the trailing _, this was clearly a mistake). This > led to the user_table (and all duplicated from it tables) to not > contain the inotify-related members. In my local testing I got > kasan splats even during kernel boot, due to out-of-bound writes. > Let's see how this version fares. Thank you I will place this in my for-testing branch shortly and see how it fares. Eric