sched, fanotify: Deal with nested sleeps
authorPeter Zijlstra <peterz@infradead.org>
Tue, 16 Dec 2014 15:28:38 +0000 (16:28 +0100)
committerIngo Molnar <mingo@kernel.org>
Fri, 9 Jan 2015 10:18:12 +0000 (11:18 +0100)
commit536ebe9ca999f6d0903d91698678ccc1742e8dd9
treefbe29b68eb805cb794154e529f56dc803115b1db
parentb74e6278fd6db5848163ccdc6e9d8eb6efdee9bd
sched, fanotify: Deal with nested sleeps

As per e23738a7300a ("sched, inotify: Deal with nested sleeps").

fanotify_read is a wait loop with sleeps in. Wait loops rely on
task_struct::state and sleeps do too, since that's the only means of
actually sleeping. Therefore the nested sleeps destroy the wait loop
state and the wait loop breaks the sleep functions that assume
TASK_RUNNING (mutex_lock).

Fix this by using the new woken_wake_function and wait_woken() stuff,
which registers wakeups in wait and thereby allows shrinking the
task_state::state changes to the actual sleep part.

Reported-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric Paris <eparis@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Eric Paris <eparis@redhat.com>
Link: http://lkml.kernel.org/r/20141216152838.GZ3337@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
fs/notify/fanotify/fanotify_user.c