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 D4EAC433BDD for ; Mon, 20 Jul 2026 15:14:58 +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=1784560500; cv=none; b=Uvi4Bm8o7AtkKYjcIQy1TztgTZ8i3YcLZDEcxNA0tdGOOUBZvgL+vCyQfjz4u7fMv00GW0pezgchY3OoGlcrHH0zVQQ0kpUqa5XEsHhiQSj5dYjRHSmZsyD05etmvGf3E9O+vdXiszowbW4jk19Wc2D1rYwCJcq5seUcDJfKkGI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784560500; c=relaxed/simple; bh=o3GqDhjf8m1ThHborRlM4O7Lbr9KmQL7TBcoGiKTKt0=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=hEXXCNYVT5OcNdLqmQdR4wUTRAiUXJJKD6fr7iaXqHDE3dP3LXaiuvgRir+boj3K4shMJlxYo9aCDfjnND/JV24grwYC3dT2XYooN2m7DjlE6bimc9+RnY9ITotEXAfUgb5DWhEEWV4D50848mv7xVUHUhs9Q/FMQX5Y+1zj90s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=M2piyIi9; 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="M2piyIi9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 471CA1F000E9; Mon, 20 Jul 2026 15:14:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784560498; bh=6PUL/awXL/wSj8XW+c0CIl0l1H8MJdq3WowrygdWT9s=; h=Subject:To:Cc:From:Date; b=M2piyIi92d7w7h5dUwvgCEW/twx0KXaQgYrcA3y1cK+ypoiPKqUyqjhjGQa/ynaU4 g3gQ/hqtFqq+5BNt5EcarCRNi4DFH2KYVESxbfhSTfFUgTlS1pLD3fhpG9jcb2UcW5 kHbKzLWzkmBjDZBX6ecAeqL+aZUAcaeAnnezEAtw= Subject: FAILED: patch "[PATCH] can: bcm: track a single source interface for ANYDEV" failed to apply to 6.1-stable tree To: socketcan@hartkopp.net,mkl@pengutronix.de Cc: From: Date: Mon, 20 Jul 2026 17:14:19 +0200 Message-ID: <2026072019-parched-village-5f94@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x 2f5976f54a04e9f18b25283036ac3136be453b17 # git commit -s git send-email --to '' --in-reply-to '2026072019-parched-village-5f94@gregkh' --subject-prefix 'PATCH 6.1.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 2f5976f54a04e9f18b25283036ac3136be453b17 Mon Sep 17 00:00:00 2001 From: Oliver Hartkopp Date: Tue, 14 Jul 2026 18:55:33 +0200 Subject: [PATCH] can: bcm: track a single source interface for ANYDEV timeout/throttle ops An ANYDEV rx op (ifindex == 0) with an active RX timeout and/or throttle timer has no defined semantics when matching frames arrive from several interfaces: bcm_rx_handler() can run concurrently for the same op on different CPUs, racing hrtimer_cancel()/ bcm_rx_starttimer() against bcm_rx_timeout_handler() and causing spurious RX_TIMEOUT notifications and last_frames corruption. The same concurrency lets throttled multiplex frames from different interfaces clobber the single rx_ifindex/rx_stamp fields shared by the op. Add op->if_detected to track the first interface that delivers a matching frame while a timeout/throttle timer is configured, and reject frames from any other interface for that op. The claim is decided in bcm_rx_handler() before hrtimer_cancel() touches op->timer, so a rejected frame can never disturb the claimed interface's watchdog. RTR-mode ops are excluded via RX_RTR_FRAME, independent of kt_ival1/kt_ival2, since those may briefly hold a stale value from an earlier non-RTR configuration. The claim is released in bcm_notify() on NETDEV_UNREGISTER and in bcm_rx_setup() when SETTIMER reconfigures the timer values. A (re-)claim is only possible on CAN devices in NETREG_REGISTERED dev->reg_state to cover the release in bcm_notify() where reg_state becomes NETREG_UNREGISTERING until synchronize_net(). Fixes: ffd980f976e7 ("[CAN]: Add broadcast manager (bcm) protocol") Reported-by: sashiko-bot@kernel.org Closes: https://lore.kernel.org/linux-can/20260709105031.1A39C1F000E9@smtp.kernel.org/ Signed-off-by: Oliver Hartkopp Link: https://patch.msgid.link/20260714-bcm_fixes-v15-11-562f7e3e42da@hartkopp.net Cc: stable@kernel.org Signed-off-by: Marc Kleine-Budde diff --git a/net/can/bcm.c b/net/can/bcm.c index f213a0b37791..3d637a1e0ac1 100644 --- a/net/can/bcm.c +++ b/net/can/bcm.c @@ -117,6 +117,7 @@ struct bcm_op { struct hrtimer timer, thrtimer; ktime_t rx_stamp, kt_ival1, kt_ival2, kt_lastmsg; int rx_ifindex; + int if_detected; /* first received ifindex in ANYDEV rx_op mode */ int cfsiz; u32 count; u32 nframes; @@ -797,6 +798,33 @@ static void bcm_rx_handler(struct sk_buff *skb, void *data) return; } + /* An ANYDEV op with an active RX timeout and/or throttle timer + * tracks a single source interface: claim the first interface that + * delivers a matching frame and reject frames from any other one, + * before hrtimer_cancel() below can touch op->timer - this avoids + * racing bcm_rx_timeout_handler() across concurrent interfaces. + * RX_RTR_FRAME ops are excluded, as kt_ival1/kt_ival2 may briefly + * hold a stale value from an earlier non-RTR configuration. + */ + if (!op->ifindex) { + spin_lock_bh(&op->bcm_rx_update_lock); + + if (!(op->flags & RX_RTR_FRAME) && + (op->kt_ival1 || op->kt_ival2)) { + /* don't claim to vanishing interface */ + if (!op->if_detected && + READ_ONCE(skb->dev->reg_state) == NETREG_REGISTERED) + op->if_detected = skb->dev->ifindex; + + if (op->if_detected != skb->dev->ifindex) { + spin_unlock_bh(&op->bcm_rx_update_lock); + return; + } + } + + spin_unlock_bh(&op->bcm_rx_update_lock); + } + /* disable timeout */ hrtimer_cancel(&op->timer); @@ -831,10 +859,9 @@ static void bcm_rx_handler(struct sk_buff *skb, void *data) traffic_flags |= RX_OWN; } - /* save rx timestamp and originator for recvfrom() under lock. - * For an op subscribed on all interfaces (ifindex == 0) - * bcm_rx_handler() can run concurrently on different CPUs so - * the CAN content and the meta data must be bundled correctly. + /* save rx timestamp and originator for recvfrom() under lock: an + * ANYDEV op without an active timer can still run concurrently on + * different CPUs, so content and meta data must be bundled here. */ op->rx_stamp = skb->tstamp; op->rx_ifindex = skb->dev->ifindex; @@ -1369,6 +1396,7 @@ static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, op->kt_ival1 = bcm_timeval_to_ktime(msg_head->ival1); op->kt_ival2 = bcm_timeval_to_ktime(msg_head->ival2); op->kt_lastmsg = 0; + op->if_detected = 0; /* reclaim ifindex in ANYDEV mode */ } spin_unlock_bh(&op->bcm_rx_update_lock); @@ -1775,10 +1803,21 @@ static void bcm_notify(struct bcm_sock *bo, unsigned long msg, lock_sock(sk); /* rx_ops: remove device specific receive entries */ - list_for_each_entry(op, &bo->rx_ops, list) + list_for_each_entry(op, &bo->rx_ops, list) { if (op->rx_reg_dev == dev) bcm_rx_unreg(dev, op); + /* release an ANYDEV op's claim (see bcm_rx_handler()) + * on this now confirmed-gone interface. + */ + if (!op->ifindex) { + spin_lock_bh(&op->bcm_rx_update_lock); + if (op->if_detected == dev->ifindex) + op->if_detected = 0; + spin_unlock_bh(&op->bcm_rx_update_lock); + } + } + /* tx_ops: stop device specific cyclic transmissions on the * vanishing ifindex. Cancelling the timer is enough to stop * cyclic bcm_can_tx() calls as there is no re-arming.