linux-stable/net/unix
WANG Cong 06a77b07e3 af_unix: conditionally use freezable blocking calls in read
Commit 2b15af6f95 ("af_unix: use freezable blocking calls in read")
converts schedule_timeout() to its freezable version, it was probably
correct at that time, but later, commit 2b514574f7
("net: af_unix: implement splice for stream af_unix sockets") breaks
the strong requirement for a freezable sleep, according to
commit 0f9548ca10:

    We shouldn't try_to_freeze if locks are held.  Holding a lock can cause a
    deadlock if the lock is later acquired in the suspend or hibernate path
    (e.g.  by dpm).  Holding a lock can also cause a deadlock in the case of
    cgroup_freezer if a lock is held inside a frozen cgroup that is later
    acquired by a process outside that group.

The pipe_lock is still held at that point.

So use freezable version only for the recvmsg call path, avoid impact for
Android.

Fixes: 2b514574f7 ("net: af_unix: implement splice for stream af_unix sockets")
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Colin Cross <ccross@android.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-11-18 13:58:39 -05:00
..
af_unix.c af_unix: conditionally use freezable blocking calls in read 2016-11-18 13:58:39 -05:00
diag.c unix_diag: fix incorrect sign extension in unix_lookup_by_ino 2016-02-19 23:49:23 -05:00
garbage.c unix: correctly track in-flight fds in sending process user_struct 2016-02-08 10:30:42 -05:00
Kconfig net: Default UDP and UNIX diag to 'n'. 2012-01-07 12:13:06 -08:00
Makefile unix_diag: Write it into kbuild 2011-12-16 13:48:29 -05:00
sysctl_net_unix.c net: Convert uses of typedef ctl_table to struct ctl_table 2013-06-13 02:36:09 -07:00