On 2/13/19 7:54 AM, Jan Kara wrote: > Hello, > > When waiting for response to fanotify permission events, we currently use > uninterruptible waits. That makes code simple however it can cause lots of > processes to end up in uninterruptible sleep with hard reboot being the only > alternative in case fanotify listener process stops responding (e.g. due to a > bug in its implementation) - reported e.g. in [1]. Uninterruptible sleep also > makes system hibernation fail if the listener gets frozen before the process > generating fanotify permission event (as reported e.g. here [2]). > > This patch set modifies fanotify so that it will use interruptible wait when > waiting for fanotify permission event response. Patches are based on current > Linus' tree for the ease of testing (I plan to rebase them on top of Amir's > pending changes later). I have also create LTP test which stresses handling of > permission events while sending processes signals to test the new code [3] > Review, comments, and testing are welcome. > > [1] https://lore.kernel.org/lkml/153474898224.6806.12518115530793064797.stgit@buzz/ > [2] https://lore.kernel.org/lkml/c1bb16b7-9eee-9cea-2c96-a512d8b3b9c7@xxxxxxxx/ > [3] https://lwn.net/ml/linux-fsdevel/20190108165307.GA11259@xxxxxxxxxxxxxx/ > > Changes since v1: > * leave pr_debug() calls alone (Amir) > * simplify permission event state tracking (Amir) > * split some changes into separate patches (Amir) > > Honza > I backported these patches to the RHEL7 kernel and have started running that. One thing I've noticed are messages like the following at login time: bash: /etc/bash_completion.d/itweb-settings.bash: Interrupted system call I've commented on a bash bug report here https://savannah.gnu.org/support/?109159 But I'm wondering if these changes are leading to more EINTR returns from open() than expected. Of if this is the new "normal", or if this points to bugs in the antivirus software holding the fanotify callbacks. Thoughts? Thanks again. -- Orion Poplawski Manager of NWRA Technical Systems 720-772-5637 NWRA, Boulder/CoRA Office FAX: 303-415-9702 3380 Mitchell Lane orion@xxxxxxxx Boulder, CO 80301 https://www.nwra.com/
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