From 8f6f8a48399f82f4a83f7b9f25b9707e0062a4f9 Mon Sep 17 00:00:00 2001 From: Adarsh Das Date: Sat, 19 Sep 2026 16:27:32 +0530 Subject: [PATCH] smb: client: delete compound mids on send failure before unlock When sending a compound request fails, smb_send_rqst() kicks off a reconnect. compound_send_recv() still has those mids on pending_mid_q, but it unlocks the server without removing them first. During reconnect, cifs_abort_connection() walks pending_mid_q and runs each mid callback. With no response yet, those callbacks return credits and drop in_flight. Then compound_send_recv()'s send-error path returns the same credits again. in_flight ends up decremented twice and smb2_add_credits() WARNs. syzbot hits this during SMB2_negotiate when the socket send fails. cifs_call_async() already calls delete_mid() before unlock on send failure. Do the same for compound chains and set cancelled_mid[] so the out: path does not delete them again. Fixes: ee258d79159a ("CIFS: Move credit processing to mid callbacks for SMB3") Reported-by: syzbot+eeb58d2197d88720a228@syzkaller.appspotmail.com Closes: https://lore.kernel.org/r/6a727d22.40259c87.584f4.04ce.GAE@google.com Tested-by: syzbot+eeb58d2197d88720a228@syzkaller.appspotmail.com Assisted-by: LLM Cc: stable@vger.kernel.org Signed-off-by: Adarsh Das Signed-off-by: Paulo Alcantara --- fs/smb/client/transport.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/smb/client/transport.c b/fs/smb/client/transport.c index e266859818a4..7df5b3447aea 100644 --- a/fs/smb/client/transport.c +++ b/fs/smb/client/transport.c @@ -965,6 +965,10 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses, if (rc < 0) { revert_current_mid(server, num_rqst); server->sequence_number -= 2; + for (i = 0; i < num_rqst; i++) { + delete_mid(server, mid[i]); + cancelled_mid[i] = true; + } } cifs_server_unlock(server);