linux/fs/notify
Jan Kara 47aaabdedf fanotify: Avoid softlockups when reading many events
When user provides large buffer for events and there are lots of events
available, we can try to copy them all to userspace without scheduling
which can softlockup the kernel (furthermore exacerbated by the
contention on notification_lock). Add a scheduling point after copying
each event.

Note that usually the real underlying problem is the cost of fanotify
event merging and the resulting contention on notification_lock but this
is a cheap way to somewhat reduce the problem until we can properly
address that.

Reported-by: Francesco Ruggeri <fruggeri@arista.com>
Link: https://lore.kernel.org/lkml/20200714025417.A25EB95C0339@us180.sjc.aristanetworks.com
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-15 15:23:28 +02:00
..
dnotify selinux/stable-5.4 PR 20190917 2019-09-23 11:21:04 -07:00
fanotify fanotify: Avoid softlockups when reading many events 2020-07-15 15:23:28 +02:00
inotify treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
fdinfo.c fsnotify: Remove proc_fs.h include 2020-05-13 17:16:14 +02:00
fdinfo.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fsnotify.c fanotify: send FAN_DIR_MODIFY event flavor with dir inode and name 2020-03-25 10:27:16 +01:00
fsnotify.h fsnotify: move declaration of fsnotify_mark_connector_cachep to fsnotify.h 2019-10-17 10:31:12 +02:00
group.c fsnotify: add mutex destroy 2020-05-13 17:14:20 +02:00
Kconfig treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mark.c fsnotify: Add missing annotation for fsnotify_finish_user_wait() and for fsnotify_prepare_user_wait() 2020-04-15 11:44:43 +02:00
notification.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 18 2019-05-21 11:28:46 +02:00