From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 4A9DE5187C2; Wed, 30 Sep 2026 17:29:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790789344; cv=none; b=kxxXfxkljWh+Tt0xmp1tCLIQ/FBPzD1p8Q2KT2Smbrt84EQ/54P7HBvnNy37yf5MywE4jRnYjtFFU58zGPXj+o84G3oRWs4Yptt0hm3tf8aEK6Wgo3qwv7KCDxr8mn4gnIoSKXKOtoJhLFVVyBEU67Xzznn616uQuD+DiB8hr1A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790789344; c=relaxed/simple; bh=WJchJ4pbjEZNVeYtTC30jLgjv1eeDUQ51LeKpmyRNEg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fmFJucO75DDPqwDnPeQsIbqqKzXTPRz6+rIgeUzvktDtiqxIWcGgex0PAMO4WO+7lATtogKZ48h6DieJFY+cGM+8jowcDr9FzZ7afCNZhI63EV1OlMTEYqj6N31D1Ey7A6/YIXDV6xw+eLS2rW+XA1BBx6SaSClCFltMn5ALWZc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ltvAhIno; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="ltvAhIno" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A6F4A1F000FF; Wed, 30 Sep 2026 17:29:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790789343; bh=TIdiDVk1s0fDq5+fGx5QXFtV0hBQDygQq+pkAYZo95g=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ltvAhInofZxR1QvfDg4i9m7tP4SI70ZluWgkkEbKpwzJQvEmJDAxjn7qIvO2dlWKr uBs8LfxuSmX4jllxVOPggrJzlUBPfUoJb+SqT2MsHm5KDVutkJOJz3LH/+E1zubsEk Bs+iAs9euqnv5gkoOsgc3p4NHh0PWpxPcbZ3WqDU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ginger Li , Tung Nguyen , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.12 442/877] tipc: Fix a data race on mon->peer_cnt in mon_timeout() Date: Wed, 30 Sep 2026 17:22:33 +0200 Message-ID: <20260930152424.220398667@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152414.738996857@linuxfoundation.org> References: <20260930152414.738996857@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ginger Li [ Upstream commit 8e1937fed6738460554ec123c64839e2445e7d53 ] mon_timeout() evaluates dom_size(mon->peer_cnt) before it takes mon->lock, while mon->peer_cnt is updated under that lock by tipc_mon_add_peer() and tipc_mon_remove_peer(). The value can therefore be stale, and the decision whether the local domain has to be recomputed can be based on an outdated member count. Read mon->peer_cnt inside the write_lock_bh(&mon->lock) protected region. Fixes: 35c55c9877f8 ("tipc: add neighbor monitoring framework") Signed-off-by: Ginger Li Reviewed-by: Tung Nguyen Link: https://patch.msgid.link/20260922080909.21123-1-ginger.jzllee@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/tipc/monitor.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/tipc/monitor.c b/net/tipc/monitor.c index b45c5b91bc7af..5e4585b034970 100644 --- a/net/tipc/monitor.c +++ b/net/tipc/monitor.c @@ -632,9 +632,10 @@ static void mon_timeout(struct timer_list *t) { struct tipc_monitor *mon = from_timer(mon, t, timer); struct tipc_peer *self; - int best_member_cnt = dom_size(mon->peer_cnt) - 1; + int best_member_cnt; write_lock_bh(&mon->lock); + best_member_cnt = dom_size(mon->peer_cnt) - 1; self = mon->self; if (self && (best_member_cnt != self->applied)) { mon_update_local_domain(mon); -- 2.53.0