| Message ID | BD33543C483B89AB+20240305061804.1186796-1-wentao@uniontech.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | fanotify: allow freeze when waiting response for permission events | expand |
On Tue 05-03-24 14:18:04, Winston Wen wrote: > This is a long-standing issue that uninterruptible sleep in fanotify > could make system hibernation fail if the usperspace server gets frozen > before the process waiting for the response (as reported e.g. [1][2]). > > A few years ago, there was an attempt to switch to interruptible sleep > while waiting [3], but that would lead to EINTR returns from open(2) > and break userspace [4], so it's been changed to only killable [5]. > > And the core freezer logic had been rewritten [6][7] in v6.1, allowing > freezing in uninterrupted sleep, so we can solve this problem now. > > [1] https://lore.kernel.org/lkml/1518774280-38090-1-git-send-email-t.vivek@samsung.com/ > [2] https://lore.kernel.org/lkml/c1bb16b7-9eee-9cea-2c96-a512d8b3b9c7@nwra.com/ > [3] https://lore.kernel.org/linux-fsdevel/20190213145443.26836-1-jack@suse.cz/ > [4] https://lore.kernel.org/linux-fsdevel/d0031e3a-f050-0832-fa59-928a80ffd44b@nwra.com/ > [5] https://lore.kernel.org/linux-fsdevel/20190221105558.GA20921@quack2.suse.cz/ > [6] https://lore.kernel.org/lkml/20220822114649.055452969@infradead.org/ > [7] https://lore.kernel.org/lkml/20230908-avoid-spurious-freezer-wakeups-v4-0-6155aa3dafae@quicinc.com/ > > Signed-off-by: Winston Wen <wentao@uniontech.com> Thanks and I'm glad this has finally a workable solution (keeping fingers crossed ;)). I've added the patch to my tree. Honza > --- > fs/notify/fanotify/fanotify.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c > index 1e4def21811e..285beaf5bc09 100644 > --- a/fs/notify/fanotify/fanotify.c > +++ b/fs/notify/fanotify/fanotify.c > @@ -228,8 +228,10 @@ static int fanotify_get_response(struct fsnotify_group *group, > > pr_debug("%s: group=%p event=%p\n", __func__, group, event); > > - ret = wait_event_killable(group->fanotify_data.access_waitq, > - event->state == FAN_EVENT_ANSWERED); > + ret = wait_event_state(group->fanotify_data.access_waitq, > + event->state == FAN_EVENT_ANSWERED, > + TASK_KILLABLE|TASK_FREEZABLE); > + > /* Signal pending? */ > if (ret < 0) { > spin_lock(&group->notification_lock); > -- > 2.43.0 >
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c index 1e4def21811e..285beaf5bc09 100644 --- a/fs/notify/fanotify/fanotify.c +++ b/fs/notify/fanotify/fanotify.c @@ -228,8 +228,10 @@ static int fanotify_get_response(struct fsnotify_group *group, pr_debug("%s: group=%p event=%p\n", __func__, group, event); - ret = wait_event_killable(group->fanotify_data.access_waitq, - event->state == FAN_EVENT_ANSWERED); + ret = wait_event_state(group->fanotify_data.access_waitq, + event->state == FAN_EVENT_ANSWERED, + TASK_KILLABLE|TASK_FREEZABLE); + /* Signal pending? */ if (ret < 0) { spin_lock(&group->notification_lock);
This is a long-standing issue that uninterruptible sleep in fanotify could make system hibernation fail if the usperspace server gets frozen before the process waiting for the response (as reported e.g. [1][2]). A few years ago, there was an attempt to switch to interruptible sleep while waiting [3], but that would lead to EINTR returns from open(2) and break userspace [4], so it's been changed to only killable [5]. And the core freezer logic had been rewritten [6][7] in v6.1, allowing freezing in uninterrupted sleep, so we can solve this problem now. [1] https://lore.kernel.org/lkml/1518774280-38090-1-git-send-email-t.vivek@samsung.com/ [2] https://lore.kernel.org/lkml/c1bb16b7-9eee-9cea-2c96-a512d8b3b9c7@nwra.com/ [3] https://lore.kernel.org/linux-fsdevel/20190213145443.26836-1-jack@suse.cz/ [4] https://lore.kernel.org/linux-fsdevel/d0031e3a-f050-0832-fa59-928a80ffd44b@nwra.com/ [5] https://lore.kernel.org/linux-fsdevel/20190221105558.GA20921@quack2.suse.cz/ [6] https://lore.kernel.org/lkml/20220822114649.055452969@infradead.org/ [7] https://lore.kernel.org/lkml/20230908-avoid-spurious-freezer-wakeups-v4-0-6155aa3dafae@quicinc.com/ Signed-off-by: Winston Wen <wentao@uniontech.com> --- fs/notify/fanotify/fanotify.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)