aboutsummaryrefslogtreecommitdiffstats
path: root/net
diff options
context:
space:
mode:
authorEric Dumazet <eric.dumazet@gmail.com>2010-11-24 09:15:27 -0800
committerDavid S. Miller <davem@davemloft.net>2010-11-24 09:15:27 -0800
commit9915672d41273f5b77f1b3c29b391ffb7732b84b (patch)
tree191dbf657535e49265be7664755890630e69e329 /net
parentcf41a51db89850033efc11c18a5257de810b5417 (diff)
downloadmrst-s0i3-test-9915672d41273f5b77f1b3c29b391ffb7732b84b.tar.gz
mrst-s0i3-test-9915672d41273f5b77f1b3c29b391ffb7732b84b.tar.xz
mrst-s0i3-test-9915672d41273f5b77f1b3c29b391ffb7732b84b.zip
af_unix: limit unix_tot_inflight
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 <vegard.nossum@gmail.com> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/unix/garbage.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/net/unix/garbage.c b/net/unix/garbage.c
index c8df6fda0b1..40df93d1cf3 100644
--- a/net/unix/garbage.c
+++ b/net/unix/garbage.c
@@ -259,9 +259,16 @@ static void inc_inflight_move_tail(struct unix_sock *u)
}
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);
}