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 3B4C4221DB6; Fri, 24 Apr 2026 13:42:36 +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=1777038156; cv=none; b=JHqUrsLckxPN8qlORKhFAy8mDh112O2nTn/ZVrqRRRRDZHQ2M75X2JKHmr0/GFDYASJKXRVXw5OZ3VtkIa3Fzo89HKpICIs/IYhoDRDBVuu5H+0MHHv1On41jIkRrEhzXEQ9STy3HGB0pJI/9u5RPVfIUVLxKI/EiOilEw+ZtHo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777038156; c=relaxed/simple; bh=XozvwGn1ntymEge3k5AghvEgFdloAPlntOCpyudLhFk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=hqRFt+uaen+JJwUrKkjSgnsAoTz7FhGg9oYIyyDYcLXaDYoqTED/6jnoBBAkPogc8gzVI1aVXqTVr7hlQzEaTGvPjFVyuZ5m186mp2aaWMkhw8PH7gEMTQSuDAF95gO9WVdOZqvRp9aZrpkrL7jAs9QYy4caP0HnZRyoVJTMS2I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=WJKaBdJU; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="WJKaBdJU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C5BB3C19425; Fri, 24 Apr 2026 13:42:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1777038156; bh=XozvwGn1ntymEge3k5AghvEgFdloAPlntOCpyudLhFk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WJKaBdJUVsjyQlUssyn0vWpuNsLdhP22DmNnn7DiqGXaSrh4D905A4nUyMThUQhZZ RG7aNBwgiUPLWdz33KSW+6j9cPfDOQXhWS1DF8ArmsdEEMvYgTB5TCXqW+CMZWzdjc 8MMdzzXZonZzJjeik836Ni/v0EozLY7WCVhN+MKY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, DaeMyung Kang , Namjae Jeon , Steve French Subject: [PATCH 6.18 45/55] ksmbd: reset rcount per connection in ksmbd_conn_wait_idle_sess_id() Date: Fri, 24 Apr 2026 15:31:24 +0200 Message-ID: <20260424132439.390292880@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260424132430.006424517@linuxfoundation.org> References: <20260424132430.006424517@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: DaeMyung Kang commit def036ef87f8641c1c525d5ae17438d7a1006491 upstream. 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: Greg Kroah-Hartman --- fs/smb/server/connection.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) --- a/fs/smb/server/connection.c +++ b/fs/smb/server/connection.c @@ -180,7 +180,7 @@ int ksmbd_conn_wait_idle_sess_id(struct { 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) @@ -189,8 +189,7 @@ retry_idle: 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,