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>
This commit is contained in:
dann frazier 2008-11-26 15:32:27 -08:00 committed by David S. Miller
parent efbbced361
commit 5f23b73496
3 changed files with 13 additions and 3 deletions

View file

@ -1343,6 +1343,7 @@ static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
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 @@ static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
if (NULL == siocb->scm)
siocb->scm = &tmp_scm;
wait_for_unix_gc();
err = scm_send(sock, msg, siocb->scm);
if (err < 0)
return err;