From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mo4-p02-ob.smtp.rzone.de (mo4-p02-ob.smtp.rzone.de [85.215.255.83]) (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 89E45427FA8 for ; Fri, 24 Jul 2026 10:22:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=85.215.255.83 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784888526; cv=pass; b=fsIG6ICFXil3N3EkbDa1e2uRGteqsVjvhFfYwlM8GOVbfpzEH/5MgMBZDxp7yU/oUcKKhlLOkZK5h0dGvR3h/3JSRae9lMX8O7QuUPGuauoIdiZTSlEy/fFJrwi60yW69+5FN5C1aLVkXayM30R4u1PK1bnDpdCsC/i0ATWEoMA= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784888526; c=relaxed/simple; bh=LU6UqsF07HhX6C54h+Nr47nWzbxg7OtMyJToV3b3czg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=oFwsskxaYYZ6X1hSG+pJrmHrV+nV/OStLBMiyuBI9xmkMMzecwNRU3W4aXW3i/NpOCVsAwzUaSTF3m9qtuEaZrq0Hr6bX8RpNW1HuxR0wP72amPB7C+D9Gf4GGvsYituX9RmcrJU6Jo4QcOdnWeJhk04YqIZ1BQGzjJoinSAQB8= 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=LRn+Yd4u; dkim=permerror (0-bit key) header.d=hartkopp.net header.i=@hartkopp.net header.b=oL6kqcYl; arc=pass smtp.client-ip=85.215.255.83 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="LRn+Yd4u"; dkim=permerror (0-bit key) header.d=hartkopp.net header.i=@hartkopp.net header.b="oL6kqcYl" ARC-Seal: i=1; a=rsa-sha256; t=1784888520; cv=none; d=strato.com; s=strato-dkim-0002; b=mZ+0z5zGMFHYUBk/5xUAQdeYsgHluAhBkNz5fUexYPMO38jHxjP9aAVNm0TyfSw0fv DILTjApHB/TBUpURjy6PDp+uvU3au8x/+6V82YMQzbo3wvPIHGWDuSD5KBDzEqqsK3nO /KzKD3NTFK32UNmwl1MB9NCkk6ZHcDs+TFw6VvGhzcSHtvIg/djJWt4Wz38W+Hs+Qcui 4xrq+/5wogVxlMaQvLFMoG302K1JoJekAl84bzDnLgx+NlBCqiD2Utco/TWpIuvjl/B+ JAw52UbSRCKaiktfsRgAmHhejvia8md/r5lPAePl15hFHhSg4rYfjNTjDHNC7xPNBjnI vqfQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; t=1784888520; 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=TInxEYReryJn3aHWwueedaQXcBtuPWDNkCUY/A3Kj28=; b=RFVFOZMZoQuIAvXYaPRCbUjBcVA4plQzAVbySrvgdD/FsNEyNJaY4/d4tnzXfEsqaE stXIqzEsyorqfHqyXrxvaTL4vnHZkvRim6PsO7+RHuHZLjM9acdzg8ASrb0B2pr6Tzg1 yKCpcmm5hNHmAWKbz+OpbQOPJ8XHj/52rBGCTBBK64+Dv660k+ZNQE/JSKMhzjBc5wCb ju+4YZnKglWDBrk+sYxA7IzenpKEr9tmwyemfkV0N5aWxwUzRRouGTwimtszX5rYBpcu wdb0YQf+I53iXXM+CRTIalY3Yanem51S892Oz3lOiEjIqB7QCu5Wt9HWuaPk8CG8jKvt hyJQ== ARC-Authentication-Results: i=1; strato.com; arc=none; dkim=none X-RZG-CLASS-ID: mo02 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1784888520; 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=TInxEYReryJn3aHWwueedaQXcBtuPWDNkCUY/A3Kj28=; b=LRn+Yd4u7WaAi9xJatItnQPMpMQ1DLQ9yhvV9mbibzl759Wgwby2ODEVibOQDmDADz gvit8HdVHygWcfrwhkUpsj2g9uy4IV6AsN+p8JyPVWqzojnEoAO79WQPNCqkNhqdgXAR 4U60ZDjwtQYn3w29AYXlC8f82j65rxUsf46UPYeLQ0NYyGvFt9PPWzu6cAtlMSV2onqq nRzWg//44p+Wxdffl3koctvyiKFK97VXlgJPhrwIDXobAm4jVFt+7qQKsT2wYKmPt/Kl 2hc7Zvh/2NuF6W04JD0jPHL7rl9yzgAQKc9zP4zfUjo7IiJQj9xnY/q57NQ+uAKhiUjA kcqg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; t=1784888520; 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=TInxEYReryJn3aHWwueedaQXcBtuPWDNkCUY/A3Kj28=; b=oL6kqcYlJCUyNzFAkPh92SAerLr9mbZzXZayBulilwaeVz2d2OipTUVMukJy69cYaU D7Luhu4BIasjfe/Th8Bg== X-RZG-AUTH: ":P2MHfkW8eP4Mre39l357AZT/I7AY/7nT2yrDxb8mjH4JKvMdQv2tRkI16oOSW1Ti/f4PoH8=" Received: from vivo.lan by smtp.strato.de (RZmta 55.5.6 SBL|AUTH) with ESMTPSA id K5281926OAM0tHh (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Fri, 24 Jul 2026 12:22:00 +0200 (CEST) From: Oliver Hartkopp To: stable@vger.kernel.org Cc: Oliver Hartkopp , Marc Kleine-Budde Subject: [PATCH 5.15.y 7/9] can: bcm: fix stale rx/tx ops after device removal Date: Fri, 24 Jul 2026 12:21:47 +0200 Message-ID: <20260724102149.16440-7-socketcan@hartkopp.net> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260724102149.16440-1-socketcan@hartkopp.net> References: <2026072036-giving-knee-3a33@gregkh> <20260724102149.16440-1-socketcan@hartkopp.net> 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 3b762c0d950383ab7a002686c9136b9aa55d2d70 upstream. RX: an RX_SETUP update(!) for an existing op skipped can_rx_register() unconditionally, even when a concurrent NETDEV_UNREGISTER had already torn down its registration (op->rx_reg_dev == NULL). This silently did not re-enable frame delivery for that updated filter. bcm_rx_setup() now re-registers in that case, while leaving rx_ops with ifindex = 0 (all CAN devices) which never carry a tracked rx_reg_dev registered as-is. TX: bcm_notify() only handled bo->rx_ops on NETDEV_UNREGISTER, leaving tx_ops with an active cyclic transmission re-arming its hrtimer indefinitely to execute bcm_tx_timeout_handler(). Cancelling the hrtimer prevents the runaway timer and any injection into a later reused ifindex, since nothing else calls bcm_can_tx() for the op until an explicit TX_SETUP update re-arms it. Unlike bcm_rx_unreg(), which clears the tracked rx_reg_dev for rx_ops, the ifindex is intentionally left unchanged for tx_ops. bcm_tx_setup() always rejects ifindex 0, so clearing it would strand the op: neither a later TX_SETUP (bcm_find_op()) nor TX_DELETE (bcm_delete_tx_op()) could ever find it again, since both require an exact ifindex match. Reported-by: sashiko-bot@kernel.org Closes: https://lore.kernel.org/linux-can/20260708094536.DDF821F00A3A@smtp.kernel.org/ Closes: https://lore.kernel.org/linux-can/20260708154039.347ED1F000E9@smtp.kernel.org/ Fixes: ffd980f976e7 ("[CAN]: Add broadcast manager (bcm) protocol") Signed-off-by: Oliver Hartkopp Link: https://patch.msgid.link/20260714-bcm_fixes-v15-9-562f7e3e42da@hartkopp.net Cc: stable@kernel.org Signed-off-by: Marc Kleine-Budde Signed-off-by: Oliver Hartkopp --- net/can/bcm.c | 54 ++++++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 44 insertions(+), 10 deletions(-) diff --git a/net/can/bcm.c b/net/can/bcm.c index eb09818..4afc2ed 100644 --- a/net/can/bcm.c +++ b/net/can/bcm.c @@ -1234,6 +1234,7 @@ static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, struct bcm_sock *bo = bcm_sk(sk); struct bcm_op *op; int do_rx_register; + int new_op = 0; int err = 0; if ((msg_head->flags & RX_FILTER_ID) || (!(msg_head->nframes))) { @@ -1318,8 +1319,15 @@ static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, /* free temporary frames / kfree(NULL) is safe */ kfree(new_frames); - /* Only an update -> do not call can_rx_register() */ - do_rx_register = 0; + /* Don't register a new CAN filter for the rx_op update unless + * a concurrent NETDEV_UNREGISTER notifier already tore down + * the previous registration. In this case the receiver needs + * to be re-registered here so that this update doesn't + * silently stop delivering frames for the given ifindex. + * Ops with ifindex = 0 (all CAN interfaces) never carry a + * tracked rx_reg_dev and stay registered as-is. + */ + do_rx_register = (ifindex && !op->rx_reg_dev) ? 1 : 0; } else { /* insert new BCM operation for the given can_id */ @@ -1389,6 +1397,7 @@ static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, /* call can_rx_register() */ do_rx_register = 1; + new_op = 1; } /* if ((op = bcm_find_op(&bo->rx_ops, msg_head->can_id, ifindex))) */ @@ -1402,7 +1411,7 @@ static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, if (op->flags & SETTIMER) { /* set timers (locked) for newly created op */ - if (do_rx_register) { + if (new_op) { spin_lock_bh(&op->bcm_rx_update_lock); op->ival1 = msg_head->ival1; op->ival2 = msg_head->ival2; @@ -1432,7 +1441,10 @@ static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, HRTIMER_MODE_REL_SOFT); } - /* now we can register for can_ids, if we added a new bcm_op */ + /* now we can register for can_ids, if we added a new bcm_op + * or need to re-register after a NETDEV_UNREGISTER tore down + * the previous registration of an existing op + */ if (do_rx_register) { if (ifindex) { struct net_device *dev; @@ -1462,18 +1474,32 @@ static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, err = -ENODEV; } - } else + } else { err = can_rx_register(sock_net(sk), NULL, op->can_id, REGMASK(op->can_id), bcm_rx_handler, op, "bcm", sk); + } + if (err) { - /* this bcm rx op is broken -> remove it */ - bcm_remove_op(op); + /* newly created bcm rx op is broken -> remove it */ + if (new_op) { + bcm_remove_op(op); + return err; + } + + /* an existing op just stays unregistered. + * Cancel op->timer and (defensively) op->thrtimer. + * Other settings can't be reached until the next + * successful RX_SETUP. + */ + hrtimer_cancel(&op->timer); + hrtimer_cancel(&op->thrtimer); return err; } - /* add this bcm_op to the list of the rx_ops */ - list_add_rcu(&op->list, &bo->rx_ops); + /* add a new bcm_op to the list of the rx_ops */ + if (new_op) + list_add_rcu(&op->list, &bo->rx_ops); } return msg_head->nframes * op->cfsiz + MHSIZ; @@ -1689,11 +1715,19 @@ static void bcm_notify(struct bcm_sock *bo, unsigned long msg, case NETDEV_UNREGISTER: lock_sock(sk); - /* remove device specific receive entries */ + /* rx_ops: remove device specific receive entries */ list_for_each_entry(op, &bo->rx_ops, list) if (op->rx_reg_dev == dev) bcm_rx_unreg(dev, op); + /* 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. + */ + list_for_each_entry(op, &bo->tx_ops, list) + if (op->ifindex == dev->ifindex) + hrtimer_cancel(&op->timer); + /* remove device reference, if this is our bound device */ if (bo->bound && bo->ifindex == dev->ifindex) { #if IS_ENABLED(CONFIG_PROC_FS) -- 2.43.0