net: Fix soft lockups/OOM issues w/ unix garbage collector
This is an implementation of David Miller's suggested fix in:
https://bugzilla.redhat.com/show_bug.cgi?id=470201
It has been updated to use wait_event() instead of
wait_event_interruptible().
Paraphrasing the description from the above report, it makes sendmsg()
block while UNIX garbage collection is in progress. This avoids a
situation where child processes continue to queue new FDs over a
AF_UNIX socket to a parent which is in the exit path and running
garbage collection on these FDs. This contention can result in soft
lockups and oom-killing of unrelated processes.
Signed-off-by: dann frazier <dannf@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index eb90f77..66d5ac4 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -1343,6 +1343,7 @@
if (NULL == siocb->scm)
siocb->scm = &tmp_scm;
+ wait_for_unix_gc();
err = scm_send(sock, msg, siocb->scm);
if (err < 0)
return err;
@@ -1493,6 +1494,7 @@
if (NULL == siocb->scm)
siocb->scm = &tmp_scm;
+ wait_for_unix_gc();
err = scm_send(sock, msg, siocb->scm);
if (err < 0)
return err;