From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 02E2337E2F5 for ; Sat, 25 Apr 2026 09:11:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777108295; cv=none; b=UbaAEeb8gPxaUcrDqCZP7CZoE70L/HfU2bqUO5E07DY/1tsKQulMEP04g6p6o/hyLE47sGtRW6MeTjmoYRYA6lPvyhQXx2rrj4Diag4lpaIGlk8kPuEywtnxkjeZ+GoBtZxgv+nKvlHK4fYTNpzsnxlaEpqPWFzm5Ni/w+SUzII= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777108295; c=relaxed/simple; bh=tuI51GDMx5anskkdW/x1fiCaSWGw72k4+7Uy2hw9MHI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=XwfdC4zr1neuNZc6cmGcRHLUvGjzz4g+Yfs7e7lbpnOAcVrQcim5q4flfrXQWldbIWCyKaeuJemhVH9NkjEXCfw08tC1xqJIhzrZN0YebvCihaE88pAOyjvdl4jewxtxg6mMf46D/uaDjBMDtlZpkhNeFIp3I4Y6O/r+BXeuD9I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=EINwQf7n; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="EINwQf7n" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A20E6C2BCB0; Sat, 25 Apr 2026 09:11:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777108294; bh=tuI51GDMx5anskkdW/x1fiCaSWGw72k4+7Uy2hw9MHI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EINwQf7n3daDAf6V+MyCT3vlIEt4034Tx+1HLDNGrJ2ClTk8cKj8eaJfxb+ho8me0 IWkoZHm2z88eEkp/Otke5tjj9XFmI7zPZQPR54xjMRA3lbOThI8tEbdc78LfL5b1z+ TdbZlHpdiNoLb354a4mERmr6ubINaVJLqXKcSTIWVbbY+D/MNKJWX5cG4vyZUKtAWv ZM9u84Sc4J7HER07SjXTKi5dTqoyOMKg7MW01/OmqzH+0BJPP6+2KrMljP1gkx8ou6 8WzINUnwD5do3+9Xo5VinFdwkFsCJ0Kx8W5Z1euL4S6rq470P4JcxvoQ7+8Vr2ZTzJ E309nWR7ruaUw== From: Sasha Levin To: stable@vger.kernel.org Cc: DaeMyung Kang , Namjae Jeon , Steve French , Sasha Levin Subject: [PATCH 6.6.y 3/3] ksmbd: reset rcount per connection in ksmbd_conn_wait_idle_sess_id() Date: Sat, 25 Apr 2026 05:11:30 -0400 Message-ID: <20260425091130.3330505-3-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260425091130.3330505-1-sashal@kernel.org> References: <2026042411-family-protrude-c6d7@gregkh> <20260425091130.3330505-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: DaeMyung Kang [ Upstream commit def036ef87f8641c1c525d5ae17438d7a1006491 ] rcount is intended to be connection-specific: 2 for curr_conn, 1 for every other connection sharing the same session. However, it is initialised only once before the hash iteration and is never reset. After the loop visits curr_conn, later sibling connections are also checked against rcount == 2, so a sibling with req_running == 1 is incorrectly treated as idle. This makes the outcome depend on the hash iteration order: whether a given sibling is checked against the loose (< 2) or the strict (< 1) threshold is decided by whether it happens to be visited before or after curr_conn. The function's contract is "wait until every connection sharing this session is idle" so that destroy_previous_session() can safely tear the session down. The latched rcount violates that contract and reopens the teardown race window the wait logic was meant to close: destroy_previous_session() may proceed before sibling channels have actually quiesced, overlapping session teardown with in-flight work on those connections. Recompute rcount inside the loop so each connection is compared against its own threshold regardless of iteration order. This is a code-inspection fix for an iteration-order-dependent logic error; a targeted reproducer would require SMB3 multichannel with in-flight work on a sibling channel landing after curr_conn in hash order, which is not something that can be triggered reliably. Fixes: 76e98a158b20 ("ksmbd: fix race condition between destroy_previous_session() and smb2 operations()") Cc: stable@vger.kernel.org Signed-off-by: DaeMyung Kang Acked-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Sasha Levin --- fs/smb/server/connection.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/fs/smb/server/connection.c b/fs/smb/server/connection.c index d9cb2c3374b07..8bd6e56804a36 100644 --- a/fs/smb/server/connection.c +++ b/fs/smb/server/connection.c @@ -179,7 +179,7 @@ int ksmbd_conn_wait_idle_sess_id(struct ksmbd_conn *curr_conn, u64 sess_id) { struct ksmbd_conn *conn; int rc, retry_count = 0, max_timeout = 120; - int rcount = 1, bkt; + int rcount, bkt; retry_idle: if (retry_count >= max_timeout) @@ -188,8 +188,7 @@ int ksmbd_conn_wait_idle_sess_id(struct ksmbd_conn *curr_conn, u64 sess_id) down_read(&conn_list_lock); hash_for_each(conn_list, bkt, conn, hlist) { if (conn->binding || xa_load(&conn->sessions, sess_id)) { - if (conn == curr_conn) - rcount = 2; + rcount = (conn == curr_conn) ? 2 : 1; if (atomic_read(&conn->req_running) >= rcount) { rc = wait_event_timeout(conn->req_running_q, atomic_read(&conn->req_running) < rcount, -- 2.53.0