Re: [PATCH 05/22] audit: Fix sleep in atomic

On Fri, Dec 23, 2016 at 9:17 AM, Paul Moore <paul(a)paul-moore.com&gt; wrote: > On Fri, Dec 23, 2016 at 8:24 AM, Jan Kara <jack(a)suse.cz&gt; wrote: >> On Thu 22-12-16 18:18:36, Paul Moore wrote: >>> On Thu, Dec 22, 2016 at 4:15 AM, Jan Kara <jack(a)suse.cz&gt; wrote: >>> > Audit tree code was happily adding new notification marks while holding >>> > spinlocks. Since fsnotify_add_mark() acquires group->mark_mutex this can >>> > lead to sleeping while holding a spinlock, deadlocks due to lock >>> > inversion, and probably other fun. Fix the problem by acquiring >>> > group->mark_mutex earlier. >>> > >>> > CC: Paul Moore <paul(a)paul-moore.com&gt; >>> > Signed-off-by: Jan Kara <jack(a)suse.cz&gt; >>> > --- >>> > kernel/audit_tree.c | 13 +++++++++++-- >>> > 1 file changed, 11 insertions(+), 2 deletions(-) >>> >>> [SIDE NOTE: this patch explains your comments and my earlier concern >>> about the locked/unlocked variants of fsnotify_add_mark() in >>> untag_chunk()] >>> >>> Ouch. Thanks for catching this ... what is your goal with these >>> patches, are you targeting this as a fix during the v4.10-rcX cycle? >>> If not, any objections if I pull this patch into the audit tree and >>> send this to Linus during the v4.10-rcX cycle (assuming it passes >>> testing, yadda yadda)? >> >> Sure, go ahead. I plan these patches for the next merge window. So I can >> rebase the series once you merge audit fixes... > > Okay, great. I'll merge this patch in the audit/stable-4.10 branch > for Linus but there will likely be some delays due to > holidays/vacation on my end. > > Thanks again for your help fixing this, I really appreciate it. I merged this patch, as well as the "Remove fsnotify_duplicate_mark()" patch (to make things cleaner when merging this patch) and did a quick test using the audit-testsuite ... the test hung on the "file_create" tests. Unfortunately, I'm traveling right now for the holidays and will not likely have a chance to debug this much further until after the new year, but I thought I would mention it in case you had some time to look into this failure. For reference, here is the audit-testsuite again: * https://github.com/linux-audit/audit-testsuite ... and if you have a Fedora test system, here is the Rawhide kernel I used to test (it is basically my kernel-secnext test kernel with those two patches mentioned above added on top): * https://copr.fedorainfracloud.org/coprs/pcmoore/kernel-testing/build/492386