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WANG Cong authored
[ Upstream commit 06a77b07 ] Commit 2b15af6f ("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 2b514574 ("net: af_unix: implement splice for stream af_unix sockets") breaks the strong requirement for a freezable sleep, according to commit 0f9548ca: 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: 2b514574 ("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> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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