diff options
| author | dann frazier <dannf@hp.com> | 2008-11-26 15:32:27 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2008-11-26 15:32:27 -0800 |
| commit | 5f23b734963ec7eaa3ebcd9050da0c9b7d143dd3 (patch) | |
| tree | f82c2265540dd5d32d64f08976cd9b6216842544 | |
| parent | efbbced361f3ff4ff9e85310ccff894185c4d904 (diff) | |
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>
| -rw-r--r-- | include/net/af_unix.h | 1 | ||||
| -rw-r--r-- | net/unix/af_unix.c | 2 | ||||
| -rw-r--r-- | net/unix/garbage.c | 13 |
3 files changed, 13 insertions, 3 deletions
diff --git a/include/net/af_unix.h b/include/net/af_unix.h index c29ff1da8a1..1614d78c60e 100644 --- a/include/net/af_unix.h +++ b/include/net/af_unix.h @@ -9,6 +9,7 @@ extern void unix_inflight(struct file *fp); extern void unix_notinflight(struct file *fp); extern void unix_gc(void); +extern void wait_for_unix_gc(void); #define UNIX_HASH_SIZE 256 diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index eb90f77bb0e..66d5ac4773a 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -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; diff --git a/net/unix/garbage.c b/net/unix/garbage.c index 6d4a9a8de5e..abb3ab34cb1 100644 --- a/net/unix/garbage.c +++ b/net/unix/garbage.c @@ -80,6 +80,7 @@ #include <linux/file.h> #include <linux/proc_fs.h> #include <linux/mutex.h> +#include <linux/wait.h> #include <net/sock.h> #include <net/af_unix.h> @@ -91,6 +92,7 @@ static LIST_HEAD(gc_inflight_list); static LIST_HEAD(gc_candidates); static DEFINE_SPINLOCK(unix_gc_lock); +static DECLARE_WAIT_QUEUE_HEAD(unix_gc_wait); unsigned int unix_tot_inflight; @@ -266,12 +268,16 @@ static void inc_inflight_move_tail(struct unix_sock *u) list_move_tail(&u->link, &gc_candidates); } -/* The external entry point: unix_gc() */ +static bool gc_in_progress = false; -void unix_gc(void) +void wait_for_unix_gc(void) { - static bool gc_in_progress = false; + wait_event(unix_gc_wait, gc_in_progress == false); +} +/* The external entry point: unix_gc() */ +void unix_gc(void) +{ struct unix_sock *u; struct unix_sock *next; struct sk_buff_head hitlist; @@ -376,6 +382,7 @@ void unix_gc(void) /* All candidates should have been detached by now. */ BUG_ON(!list_empty(&gc_candidates)); gc_in_progress = false; + wake_up(&unix_gc_wait); out: spin_unlock(&unix_gc_lock); |