Apologies for the previous HTML email, my bad. Yes, it does make sense for inclusion in 4.9. I went and tested 4.9, saw the same hang, and backported the relevant patches. 4.9 requires only 3 of the 5 needed for 4.4. I sent the patchset to the list, you should see them soon. Let me know if there's anything else you need. Thanks, Matthew On 11/04/19 4:44 AM, Sasha Levin wrote: > On Wed, Apr 10, 2019 at 04:54:51PM +1200, Matthew Ruffell wrote: >> BugLink: https://bugs.launchpad.net/bugs/1775165 >> >> [Note to upstream] >> I understand that this patch is a little long for -stable, but this patch series >> fixes a real issue, seen by real users, is testable, and is made up from >> upstream commits. Please consider it. >> >> [Impact] >> >> When userspace tasks which are processing fanotify permission events act >> incorrectly, the fsnotify_mark_srcu SRCU is held indefinitely which causes >> the whole notification subsystem to hang. >> >> This has been seen in production, and it can also be seen when running the >> Linux Test Project testsuite, specifically fanotify07. >> >> [Fix] >> >> Instead of holding the SRCU lock while waiting for userspace to respond, >> which may never happen, or not in the order we are expecting, we drop the >> fsnotify_mark_srcu SRCU lock before waiting for userspace response, and then >> reacquire the lock again when userspace responds. >> >> The fixes are from a series of upstream commits: >> >> 05f0e38724e8449184acd8fbf0473ee5a07adc6c (cherry-pick) >> 9385a84d7e1f658bb2d96ab798393e4b16268aaa (backport) >> abc77577a669f424c5d0c185b9994f2621c52aa4 (backport) >> >> The following are upstream commits necessary for the fixes to function: >> >> 35e481761cdc688dbee0ef552a13f49af8eba6cc (backport) >> 0918f1c309b86301605650c836ddd2021d311ae2 (cherry-pick) > > This would also make sense for 4.9, right? I don't want to fix 4.4 > without fixing 4.9 as well. > > -- > Thanks, > Sasha
