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 2b514574f7e8
("net: af_unix: implement splice for stream af_unix sockets") breaks
the strong requirement for a freezable sleep, according to
commit 0f9548ca1091:
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 just revert commit 2b15af6f95.
Reported-by: Dmitry Vyukov <dvyu...@google.com>
Cc: Tejun Heo <t...@kernel.org>
Cc: Colin Cross <ccr...@android.com>
Cc: Rafael J. Wysocki <rafael.j.wyso...@intel.com>
Signed-off-by: Cong Wang <xiyou.wangc...@gmail.com>
---
net/unix/af_unix.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 5d1c14a..6f37f9e 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -116,7 +116,6 @@
#include <linux/mount.h>
#include <net/checksum.h>
#include <linux/security.h>
-#include <linux/freezer.h>
struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE];
EXPORT_SYMBOL_GPL(unix_socket_table);
@@ -2220,7 +2219,7 @@ static long unix_stream_data_wait(struct sock *sk, long
timeo,
sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
unix_state_unlock(sk);
- timeo = freezable_schedule_timeout(timeo);
+ timeo = schedule_timeout(timeo);
unix_state_lock(sk);
if (sock_flag(sk, SOCK_DEAD))
--
2.1.0
