diff options
| author | Eric Dumazet <eric.dumazet@gmail.com> | 2010-11-24 09:15:27 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-11-24 09:15:27 -0800 |
| commit | 9915672d41273f5b77f1b3c29b391ffb7732b84b (patch) | |
| tree | 191dbf657535e49265be7664755890630e69e329 | |
| parent | cf41a51db89850033efc11c18a5257de810b5417 (diff) | |
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>
| -rw-r--r-- | net/unix/garbage.c | 7 |
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); } |