From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mo4-p03-ob.smtp.rzone.de (mo4-p03-ob.smtp.rzone.de [85.215.255.103]) (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 2D1983AD51E for ; Fri, 24 Jul 2026 08:42:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=85.215.255.103 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784882536; cv=pass; b=Mu5QhvaqHPK5FgJYLk8q98wRSVHRgxKm9dutx9frvBN7CE1jdIQ8cbRDGUUAmJ01pIA/YSAXBl8EMwXqMC+b7JREIVu+AtuSwvdwTt621jxn1EDb6sAPv4c+fAmU9TbmBk0dRl9HIgZUd6pZY15Jn2Z4Q1s6MS4fDJJbiNp9+5g= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784882536; c=relaxed/simple; bh=2rLAWQri+3QKdSPAllCIrU2beGxN7SchfOZDVCf1Jg4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Sz56ABRsJPjFGXcerNKF1UHbITr8CC6BSf3yNQc61xmuFJlfLB6rpJnZWEjIfA90W2ll/pVrndrO/e339TlUxH+02wiZuqk2ZOXFR1+xetQ0kkmgKRSaFpKv8lSBZmC7ArrwEG6pHHA0Hmrc8w1vfw1wOFzVbXAFhYD6rYPtVjs= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=hartkopp.net; spf=fail smtp.mailfrom=hartkopp.net; dkim=pass (2048-bit key) header.d=hartkopp.net header.i=@hartkopp.net header.b=dr/oZh6q; dkim=permerror (0-bit key) header.d=hartkopp.net header.i=@hartkopp.net header.b=KkrbaY14; arc=pass smtp.client-ip=85.215.255.103 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=hartkopp.net Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=hartkopp.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=hartkopp.net header.i=@hartkopp.net header.b="dr/oZh6q"; dkim=permerror (0-bit key) header.d=hartkopp.net header.i=@hartkopp.net header.b="KkrbaY14" ARC-Seal: i=1; a=rsa-sha256; t=1784882532; cv=none; d=strato.com; s=strato-dkim-0002; b=Zizd9le55HvmtwS0USQqCPlEimkAnidFdukAMbFj2kMb5yAlcrsq68XxBPI+V4Gsfg kMV37NoGMZfolJ+s67l45vwQn5TKtWi+nhKnM6JtZZctDqrk/7eQEsbV8FuPM3KBOVNE iaIE6d7bkMOPOuIg0zaTYC/fGvC34/042sK0wqyJq+cp50y1KwTrhPFWdoUWXH+63jZF 8VlN0maEx7SLRZ8KLQ0eMqRfXfR2/cg9fZup+yeQVdAY7hxhXUCdH3ChB0nBkJB44+FL 8eASh7pSLbzgi3+5IYWsJBgklFg+TooOfr6Hw/nIw3WEih0qyv3qWzbo2G+qzj+v9egZ YGnQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; t=1784882532; s=strato-dkim-0002; d=strato.com; h=References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Cc:Date: From:Subject:Sender; bh=WENBExdGgXH0Y8EG7CtE8QwByCeIgwV0MfpisqvHjVs=; b=OljrhQVM971UbEFqbP/Vomm4ZZdUqcFv1noIELxdT/xfBldm/7IHynsHzBQ5CvMkWL Blv4Z9yvfO1IXuiTKzB3hzJW1Iftq7e6GcOcXccQdLD/sdnJtRaMuL00JFYVuIzV5+9u R9ZZhDqxtVVvWz+VNlntR5Up8wWrIRmEEf6qrVSeAOmE0+b/rQLgX4mRrcXoj44A2OhV IcPQ2LFEfyPvaSCjCfodV9ZKlNXNAp5YtpOHNVJwkKg4TMNqajixZYYtNkO8aEEMfia0 Y6fh5KWhJ3s4nnE5SLUCHiQX3seiPKBekhwIz+bZqD81JclO2cBI74BB4WKoTZ9h6cfr URZw== ARC-Authentication-Results: i=1; strato.com; arc=none; dkim=none X-RZG-CLASS-ID: mo03 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1784882532; s=strato-dkim-0002; d=hartkopp.net; h=References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Cc:Date: From:Subject:Sender; bh=WENBExdGgXH0Y8EG7CtE8QwByCeIgwV0MfpisqvHjVs=; b=dr/oZh6qsEYJc21ZaBCv3r5wHKPfUxzsBx93NVduATeIElp08V86BqP+eiaZKovhGL BueKK9N1uNww3vYKpUWmhUDNRUY2OJgtY2vxvbWrMsOxDcKE3vDe0LuoE0WTjoP6vBwQ I3awbaL6xdDQMC/P5u9gZQvJb1aNS7trQZuE6P7OYB5eu/xIyw+yPK6z9jrT89nA022h Rg5twlryz7o/TBxXumgjZXIFRSkIZvDz1xd8ITXgUGn2ZjNT2hoCjcMDCeC3PA0tiYeo pbCIuNlGYJXJ7eplgCjpR5X8zpmxHaTA0L5a8wWGEyJKUGjLCFxRN7uhR/zs2V8HDXK5 xWRg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; t=1784882532; s=strato-dkim-0003; d=hartkopp.net; h=References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Cc:Date: From:Subject:Sender; bh=WENBExdGgXH0Y8EG7CtE8QwByCeIgwV0MfpisqvHjVs=; b=KkrbaY14RhjtJ3XrXcalcp7gDBnK3IgFW0piiUTqssSREl1xneHoXdBY9hAgUHRdGX +YyCel/S4eBXT4Fn1fDg== X-RZG-AUTH: ":P2MHfkW8eP4Mre39l357AZT/I7AY/7nT2yrDxb8mjH4JKvMdQv2tRkI16oOSW1Ti/f4PoH8=" Received: from vivo.lan by smtp.strato.de (RZmta 55.5.6 SBL|AUTH) with ESMTPSA id K5281926O8gCrXT (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Fri, 24 Jul 2026 10:42:12 +0200 (CEST) From: Oliver Hartkopp To: stable@vger.kernel.org Cc: Oliver Hartkopp , Marc Kleine-Budde Subject: [PATCH 8/8] can: bcm: track a single source interface for ANYDEV timeout/throttle ops Date: Fri, 24 Jul 2026 10:42:04 +0200 Message-ID: <20260724084204.13169-9-socketcan@hartkopp.net> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026072018-crouch-islamic-d0cb@gregkh> References: <2026072018-crouch-islamic-d0cb@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="us-ascii" commit 2f5976f54a04e9f18b25283036ac3136be453b17 upstream. 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 Signed-off-by: Oliver Hartkopp --- net/can/bcm.c | 49 ++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 44 insertions(+), 5 deletions(-) diff --git a/net/can/bcm.c b/net/can/bcm.c index ef9eafb..455eecb 100644 --- a/net/can/bcm.c +++ b/net/can/bcm.c @@ -116,6 +116,7 @@ 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; @@ -791,6 +792,33 @@ 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 && + 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); @@ -825,10 +853,9 @@ 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; @@ -1363,6 +1390,7 @@ 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); @@ -1763,10 +1791,21 @@ 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. -- 2.43.0