summaryrefslogtreecommitdiff
path: root/net
diff options
context:
space:
mode:
authorEric Dumazet <eric.dumazet@gmail.com>2010-11-24 09:15:27 -0800
committerGreg Kroah-Hartman <gregkh@suse.de>2011-01-07 13:58:26 -0800
commitf7e86272f0b8fcc627c3d4a42db21419f1995b9a (patch)
treeb2d0642f9532cb3c9f7f8394a2fb432df4ca8efd /net
parent306030ab289880475a63ebab1948ea300ec46d89 (diff)
af_unix: limit unix_tot_inflight
[ 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 <vegard.nossum@gmail.com> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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 c8df6fda0b1f..40df93d1cf35 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);
}