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 59590263F44; Sat, 30 May 2026 17:24:59 +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=1780161900; cv=none; b=DEJlN6lYkvcTnokAAgzhdNJR12c5/mGH+IiHaQ8iEnNCgj/P533LDFo0N0OWsL3oeLJQglFmO/HNmO6ZuikpHsjrfm0B0ZsGcyKDj3Pn1VKFt1cpoXM9X/95hMJa0QA6x50gGzomleRR1HOxUrQfBlPRHyR3pgSjAS3tAIBkJk0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780161900; c=relaxed/simple; bh=HcrIldPu+YPVG702srQA4iqQ128R5LXoe7KJSaK0UPE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=r4bcCfzGatq3v1aG4IeU3c6CWTcypHPqGjrlgtf2N2zPBL0bg1WkS09U/FfZul17a/G1oYpgrmiXcxyUaKvgiYgdZzJNdFn2YMG3TyEA3MTt131xtsjQlDHAAB2sNr8PUpBH0AwG75xo/RKMz5gKmQcyW4ROSfRsarO5qE47wrs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=q0UouiV3; 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="q0UouiV3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 62AEA1F00893; Sat, 30 May 2026 17:24:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780161899; bh=6YzQ/hMf7KEDDQqlfZVSV/6JbJwADLC8TS8pEyYSHZw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=q0UouiV3XIispF4t9Irtkv/LzAX+imWHxObRJmmeB5gd1jd5217J0mitWZZmw6EoF Hr0CyxKRRNeoVmEJqumIKdSvhcamsWESLzxNUQjHvTK/yMer00pAiZwQvsGzXgoGJV O1SxooXqIDk9Lu05FT/3e4WY5XinsgsP8wiSvu7E= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "William A. Kennington III" , Jeremy Kerr , Paolo Abeni , Sasha Levin Subject: [PATCH 6.1 759/969] net: mctp i2c: check length before marking flow active Date: Sat, 30 May 2026 18:04:43 +0200 Message-ID: <20260530160321.524804176@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260530160300.485627683@linuxfoundation.org> References: <20260530160300.485627683@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 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: William A. Kennington III [ Upstream commit 4ca07b9239bd0478ae586632a2ed72be37ed8407 ] Currently, mctp_i2c_get_tx_flow_state() is called before the packet length sanity check. This function marks a new flow as active in the MCTP core. If the sanity check fails, mctp_i2c_xmit() returns early without calling mctp_i2c_lock_nest(). This results in a mismatched locking state: the flow is active, but the I2C bus lock was never acquired for it. When the flow is later released, mctp_i2c_release_flow() will see the active state and queue an unlock marker. The TX thread will then decrement midev->i2c_lock_count from 0, causing it to underflow to -1. This underflow permanently breaks the driver's locking logic, allowing future transmissions to occur without holding the I2C bus lock, leading to bus collisions and potential hardware hangs. Move the mctp_i2c_get_tx_flow_state() call to after the length sanity check to ensure we only transition the flow state if we are actually going to proceed with the transmission and locking. Fixes: f5b8abf9fc3d ("mctp i2c: MCTP I2C binding driver") Signed-off-by: William A. Kennington III Acked-by: Jeremy Kerr Link: https://patch.msgid.link/20260423074741.201460-1-william@wkennington.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- drivers/net/mctp/mctp-i2c.c | 4 ++-- net/sched/cls_flower.c | 4 +++- 2 files changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/net/mctp/mctp-i2c.c b/drivers/net/mctp/mctp-i2c.c index 2eeccc3b70eff..cf0947b64a123 100644 --- a/drivers/net/mctp/mctp-i2c.c +++ b/drivers/net/mctp/mctp-i2c.c @@ -461,8 +461,6 @@ static void mctp_i2c_xmit(struct mctp_i2c_dev *midev, struct sk_buff *skb) u8 *pecp; int rc; - fs = mctp_i2c_get_tx_flow_state(midev, skb); - hdr = (void *)skb_mac_header(skb); /* Sanity check that packet contents matches skb length, * and can't exceed MCTP_I2C_BUFSZ @@ -474,6 +472,8 @@ static void mctp_i2c_xmit(struct mctp_i2c_dev *midev, struct sk_buff *skb) return; } + fs = mctp_i2c_get_tx_flow_state(midev, skb); + if (skb_tailroom(skb) >= 1) { /* Linear case with space, we can just append the PEC */ skb_put(skb, 1); diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c index a40a9e84c75f4..fd8c2f0f3256e 100644 --- a/net/sched/cls_flower.c +++ b/net/sched/cls_flower.c @@ -537,6 +537,7 @@ static int __fl_delete(struct tcf_proto *tp, struct cls_fl_filter *f, struct netlink_ext_ack *extack) { struct cls_fl_head *head = fl_head_dereference(tp); + struct fl_flow_mask *mask; *last = false; @@ -553,11 +554,12 @@ static int __fl_delete(struct tcf_proto *tp, struct cls_fl_filter *f, list_del_rcu(&f->list); spin_unlock(&tp->lock); - *last = fl_mask_put(head, f->mask); + mask = f->mask; if (!tc_skip_hw(f->flags)) fl_hw_destroy_filter(tp, f, rtnl_held, extack); tcf_unbind_filter(tp, &f->res); __fl_put(f); + *last = fl_mask_put(head, mask); return 0; } -- 2.53.0