linux/net/unix
Miklos Szeredi 6209344f5a 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>
2008-11-09 11:17:33 -08:00
..
af_unix.c net: unix: fix inflight counting bug in garbage collector 2008-11-09 11:17:33 -08:00
garbage.c net: unix: fix inflight counting bug in garbage collector 2008-11-09 11:17:33 -08:00
Kconfig [NET]: move config options out to individual protocols 2005-07-11 21:13:56 -07:00
Makefile
sysctl_net_unix.c [NETNS]: struct net content re-work (v3) 2008-01-28 14:57:14 -08:00