From db51a8658c11a82432b64999519a269c3aabb447 Mon Sep 17 00:00:00 2001 From: Hidayath Khan Date: Thu, 20 Aug 2026 09:46:41 +0200 Subject: [PATCH] net/smc: stop killed, freed and out_of_sync sharing a byte The three connection state flags are single-bit bitfields, so they occupy one byte of struct smc_connection and every store to one is a read-modify-write of the other two: u8 killed : 1; u8 freed : 1; u8 out_of_sync : 1; They are not written under a common lock. smc_cdc_msg_validate() sets out_of_sync from the receive tasklet, while smc_conn_kill() sets killed from process context under lock_sock(), and the receive path does not defer to the backlog when the socket is owned -- smc_cdc_msg_recv() takes only bh_lock_sock(). Give each flag its own byte so a store no longer touches its neighbours. All readers test them as booleans and are unchanged. struct smc_connection grows by two bytes. Fixes: b286a0651e44 ("net/smc: handle incoming CDC validation message") Cc: stable@vger.kernel.org Reviewed-by: Mahanta Jambigi Signed-off-by: Hidayath Khan Reviewed-by: Simon Horman Link: https://patch.msgid.link/20260820074642.966856-2-hidayath@linux.ibm.com Signed-off-by: Jakub Kicinski --- net/smc/smc.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/smc/smc.h b/net/smc/smc.h index 52145df83f6e..427b6d63b993 100644 --- a/net/smc/smc.h +++ b/net/smc/smc.h @@ -277,9 +277,9 @@ struct smc_connection { * 0 for SMC-R, 32 for SMC-D */ u64 peer_token; /* SMC-D token of peer */ - u8 killed : 1; /* abnormal termination */ - u8 freed : 1; /* normal termination */ - u8 out_of_sync : 1; /* out of sync with peer */ + u8 killed; /* abnormal termination */ + u8 freed; /* normal termination */ + u8 out_of_sync; /* out of sync with peer */ }; struct smc_sock { /* smc sock container */