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| author | Miklos Szeredi <mszeredi@suse.cz> | 2008-11-09 15:23:57 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-11-09 20:17:33 +0100 |
| commit | 6209344f5a3795d34b7f2c0061f49802283b6bdd (patch) | |
| tree | 5c037ddbb8caac17b0c6101c9ab86387df106d41 /include/net | |
| parent | clarify usage expectations for cnt32_to_63() (diff) | |
| download | linux-6209344f5a3795d34b7f2c0061f49802283b6bdd.tar.xz linux-6209344f5a3795d34b7f2c0061f49802283b6bdd.zip | |
net: unix: fix inflight counting bug in garbage collector
Previously I assumed that the receive queues of candidates don't
change during the GC. This is only half true, nothing can be received
from the queues (see comment in unix_gc()), but buffers could be added
through the other half of the socket pair, which may still have file
descriptors referring to it.
This can result in inc_inflight_move_tail() erronously increasing the
"inflight" counter for a unix socket for which dec_inflight() wasn't
previously called. This in turn can trigger the "BUG_ON(total_refs <
inflight_refs)" in a later garbage collection run.
Fix this by only manipulating the "inflight" counter for sockets which
are candidates themselves. Duplicating the file references in
unix_attach_fds() is also needed to prevent a socket becoming a
candidate for GC while the skb that contains it is not yet queued.
Reported-by: Andrea Bittau <a.bittau@cs.ucl.ac.uk>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
CC: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/net')
| -rw-r--r-- | include/net/af_unix.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/net/af_unix.h b/include/net/af_unix.h index 7dd29b7e461d..c29ff1da8a18 100644 --- a/include/net/af_unix.h +++ b/include/net/af_unix.h @@ -54,6 +54,7 @@ struct unix_sock { atomic_long_t inflight; spinlock_t lock; unsigned int gc_candidate : 1; + unsigned int gc_maybe_cycle : 1; wait_queue_head_t peer_wait; }; #define unix_sk(__sk) ((struct unix_sock *)__sk) |