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| author | Kuniyuki Iwashima <kuniyu@amazon.com> | 2025-05-21 14:45:30 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-06-04 14:42:23 +0200 |
| commit | 3600729b7fc0564ccb1ceec493fa446858b6d95b (patch) | |
| tree | ef44cbf6c05347ec1dadef8dd15a582abf1f2252 /include/net | |
| parent | 7b1ffbd3b22e755d481d49647dcb7c5cfbde5844 (diff) | |
| download | linux-3600729b7fc0564ccb1ceec493fa446858b6d95b.tar.gz linux-3600729b7fc0564ccb1ceec493fa446858b6d95b.tar.bz2 linux-3600729b7fc0564ccb1ceec493fa446858b6d95b.zip | |
af_unix: Try not to hold unix_gc_lock during accept().
commit fd86344823b521149bb31d91eba900ba3525efa6 upstream.
Commit dcf70df2048d ("af_unix: Fix up unix_edge.successor for embryo
socket.") added spin_lock(&unix_gc_lock) in accept() path, and it
caused regression in a stress test as reported by kernel test robot.
If the embryo socket is not part of the inflight graph, we need not
hold the lock.
To decide that in O(1) time and avoid the regression in the normal
use case,
1. add a new stat unix_sk(sk)->scm_stat.nr_unix_fds
2. count the number of inflight AF_UNIX sockets in the receive
queue under unix_state_lock()
3. move unix_update_edges() call under unix_state_lock()
4. avoid locking if nr_unix_fds is 0 in unix_update_edges()
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202404101427.92a08551-oliver.sang@intel.com
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20240413021928.20946-1-kuniyu@amazon.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Lee Jones <lee@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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 47042de4a2a9..b6eedf7650da 100644 --- a/include/net/af_unix.h +++ b/include/net/af_unix.h @@ -67,6 +67,7 @@ struct unix_skb_parms { struct scm_stat { atomic_t nr_fds; + unsigned long nr_unix_fds; }; #define UNIXCB(skb) (*(struct unix_skb_parms *)&((skb)->cb)) |