This is a note to let you know that I've just added the patch titled
af_unix: limit unix_tot_inflight
to the 2.6.36-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
af_unix-limit-unix_tot_inflight.patch
and it can be found in the queue-2.6.36 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From b13723cb6f2a7b7d9ef39a1afca59e942fdf6fcd Mon Sep 17 00:00:00 2001
From: Eric Dumazet <[email protected]>
Date: Wed, 24 Nov 2010 09:15:27 -0800
Subject: af_unix: limit unix_tot_inflight
From: Eric Dumazet <[email protected]>
[ Upstream commit 9915672d41273f5b77f1b3c29b391ffb7732b84b ]
Vegard Nossum found a unix socket OOM was possible, posting an exploit
program.
My analysis is we can eat all LOWMEM memory before unix_gc() being
called from unix_release_sock(). Moreover, the thread blocked in
unix_gc() can consume huge amount of time to perform cleanup because of
huge working set.
One way to handle this is to have a sensible limit on unix_tot_inflight,
tested from wait_for_unix_gc() and to force a call to unix_gc() if this
limit is hit.
This solves the OOM and also reduce overall latencies, and should not
slowdown normal workloads.
Reported-by: Vegard Nossum <[email protected]>
Signed-off-by: Eric Dumazet <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
net/unix/garbage.c | 7 +++++++
1 file changed, 7 insertions(+)
--- a/net/unix/garbage.c
+++ b/net/unix/garbage.c
@@ -259,9 +259,16 @@ static void inc_inflight_move_tail(struc
}
static bool gc_in_progress = false;
+#define UNIX_INFLIGHT_TRIGGER_GC 16000
void wait_for_unix_gc(void)
{
+ /*
+ * If number of inflight sockets is insane,
+ * force a garbage collect right now.
+ */
+ if (unix_tot_inflight > UNIX_INFLIGHT_TRIGGER_GC && !gc_in_progress)
+ unix_gc();
wait_event(unix_gc_wait, gc_in_progress == false);
}
Patches currently in stable-queue which might be from [email protected] are
queue-2.6.36/tcp-protect-sysctl_tcp_cookie_size-reads.patch
queue-2.6.36/tcp-don-t-change-unlocked-socket-state-in-tcp_v4_err.patch
queue-2.6.36/net-dst-dst_dev_event-called-after-other-notifiers.patch
queue-2.6.36/pppoe.c-fix-kernel-panic-caused-by-__pppoe_xmit.patch
queue-2.6.36/net-fix-skb_defer_rx_timestamp.patch
queue-2.6.36/filter-fix-sk_filter-rcu-handling.patch
queue-2.6.36/af_unix-limit-unix_tot_inflight.patch
queue-2.6.36/llc-fix-a-device-refcount-imbalance.patch
queue-2.6.36/af_unix-limit-recursion-level.patch
queue-2.6.36/tcp-avoid-a-possible-divide-by-zero.patch
_______________________________________________
stable mailing list
[email protected]
http://linux.kernel.org/mailman/listinfo/stable
