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 B6E4652ED3C; Thu, 17 Sep 2026 15:30:55 +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=1789659059; cv=none; b=m+yBsgMmGaQLLeJdSFzRflB+BpN+N8ROS8zov+ys4vwvJxx+Jap2x+A2/MDozSp5aBfwhinITCvoq3QyytPCUeJwu6dvyo9v8TXZMLsA8yfmbMHDSb1ijOlnab+u9pOL66hIWlBV9UuaX+pIrJCJ+tQAhMu5nDxPornH6WVoj9k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789659059; c=relaxed/simple; bh=W585pMIAqc7YdwjlTlFdA1Ab//GcFfLEusjhGIJVSYg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Xdte4COF72164KypKDiZbbO+ZAupW8jVt7IN2ehvmdgHhwRANRmkoaMkYfXLC9cbbvczDo4jOcHDUNM5ni5Ltpataeof3456qL5o7TpC49xVQQE+6ntqNMBZyi1KCnwEm2xRP7J8oVmI/WW0meXSzGzxtIVryfDpopmaQbTpWCw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=TYr52R3z; 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="TYr52R3z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 80BA21F00898; Thu, 17 Sep 2026 15:30:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789659055; bh=bdDJ6zzAjEJQOAHEv1jt3rguB/QzmaUP3OERxns5gP8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=TYr52R3zWAG/achWLL9gpmXtInC6LVVZg19uqBfSc5wkeIpQpXUl0EzB3lcnmE6Jl vD/USOWnoKR4KyNodffdaXRAA+cpVkSiS5wDtswVS2lHTayD1iXt1Z5mcPjY/NjTRE gnC2xnuFYyDsjgTo7eYCQL0hmwK3oJDmkKfjC/g4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Selvamani Rajagopal , Jakub Kicinski , Sasha Levin Subject: [PATCH 7.2 129/733] net: ethernet: oa_tc6: Protect skb pointer used by two different kernel instances Date: Thu, 17 Sep 2026 16:07:17 +0100 Message-ID: <20260917151354.236433262@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260917151350.597953846@linuxfoundation.org> References: <20260917151350.597953846@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 7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Selvamani Rajagopal [ Upstream commit 5443d9c4f55d46634b95432e1e8a40b824019bbb ] Threaded IRQ uses waiting_tx_skb. Transmit path also uses this pointer without any mutual exclusion protection. As a result, it might leak skb buffer, particularly if threaded IRQ sets disable_traffic true after start_xmit already checked and found that disable_traffic being false, if they happen to run on different cores. On fatal error, where disable_traffic is set, transmit function drops the packet and return NETDEV_TX_OK. Due to this change, skb_linearize call is moved up to the beginning of the transmit function. Since skb buffer may be freed from different contexts, dev_kfree_skb_any is used to free skb buffer now, replacing one of the kfree_skb call. oa_tc6_exit disables the irq before setting disable_traffic true. Fixes: b542d13fab0f ("net: ethernet: oa_tc6: Interrupt is active low, level triggered.") Signed-off-by: Selvamani Rajagopal Link: https://patch.msgid.link/20260824-fix-race-condition-and-crash-v7-1-4323279b18f2@onsemi.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/ethernet/oa_tc6.c | 109 ++++++++++++++++++++++++---------- 1 file changed, 76 insertions(+), 33 deletions(-) diff --git a/drivers/net/ethernet/oa_tc6.c b/drivers/net/ethernet/oa_tc6.c index fb219542e90d3..d283e81358e65 100644 --- a/drivers/net/ethernet/oa_tc6.c +++ b/drivers/net/ethernet/oa_tc6.c @@ -639,6 +639,26 @@ static int oa_tc6_enable_data_transfer(struct oa_tc6 *tc6) return oa_tc6_write_register(tc6, OA_TC6_REG_CONFIG0, value); } +/* Called when a frame that is meant to be transmitted, is dropped. */ +static void oa_tc6_drop_tx_skb(struct oa_tc6 *tc6, struct sk_buff *skb) +{ + if (skb) { + tc6->netdev->stats.tx_dropped++; + dev_kfree_skb_any(skb); + } +} + +static struct sk_buff *oa_tc6_detach_waiting_tx_skb(struct oa_tc6 *tc6) +{ + struct sk_buff *skb; + + lockdep_assert_held(&tc6->tx_skb_lock); + skb = tc6->waiting_tx_skb; + tc6->waiting_tx_skb = NULL; + + return skb; +} + static void oa_tc6_cleanup_ongoing_rx_skb(struct oa_tc6 *tc6) { if (tc6->rx_skb) { @@ -650,26 +670,30 @@ static void oa_tc6_cleanup_ongoing_rx_skb(struct oa_tc6 *tc6) static void oa_tc6_cleanup_ongoing_tx_skb(struct oa_tc6 *tc6) { - if (tc6->ongoing_tx_skb) { - tc6->netdev->stats.tx_dropped++; - kfree_skb(tc6->ongoing_tx_skb); - tc6->ongoing_tx_skb = NULL; - } + oa_tc6_drop_tx_skb(tc6, tc6->ongoing_tx_skb); + tc6->ongoing_tx_skb = NULL; } static void oa_tc6_cleanup_waiting_tx_skb(struct oa_tc6 *tc6) { - if (tc6->waiting_tx_skb) { - tc6->netdev->stats.tx_dropped++; - kfree_skb(tc6->waiting_tx_skb); - tc6->waiting_tx_skb = NULL; - } + struct sk_buff *skb; + + spin_lock_bh(&tc6->tx_skb_lock); + skb = oa_tc6_detach_waiting_tx_skb(tc6); + spin_unlock_bh(&tc6->tx_skb_lock); + + oa_tc6_drop_tx_skb(tc6, skb); } -static void oa_tc6_free_pending_skbs(struct oa_tc6 *tc6) +static void oa_tc6_free_ongoing_skbs(struct oa_tc6 *tc6) { oa_tc6_cleanup_ongoing_tx_skb(tc6); oa_tc6_cleanup_ongoing_rx_skb(tc6); +} + +static void oa_tc6_free_pending_skbs(struct oa_tc6 *tc6) +{ + oa_tc6_free_ongoing_skbs(tc6); oa_tc6_cleanup_waiting_tx_skb(tc6); } @@ -680,9 +704,15 @@ static void oa_tc6_free_pending_skbs(struct oa_tc6 *tc6) static void oa_tc6_disable_traffic(struct oa_tc6 *tc6) { u32 regval = OA_TC6_INT_MASK0_ALL_INTERRUPTS; + struct sk_buff *skb; + spin_lock_bh(&tc6->tx_skb_lock); tc6->disable_traffic = true; - oa_tc6_free_pending_skbs(tc6); + skb = oa_tc6_detach_waiting_tx_skb(tc6); + spin_unlock_bh(&tc6->tx_skb_lock); + + oa_tc6_drop_tx_skb(tc6, skb); + oa_tc6_free_ongoing_skbs(tc6); oa_tc6_write_register(tc6, OA_TC6_REG_INT_MASK0, regval); oa_tc6_read_register(tc6, OA_TC6_REG_STATUS0, ®val); oa_tc6_write_register(tc6, OA_TC6_REG_STATUS0, regval); @@ -1123,8 +1153,7 @@ static int oa_tc6_try_spi_transfer(struct oa_tc6 *tc6) if (ret == -EAGAIN) continue; - oa_tc6_cleanup_ongoing_tx_skb(tc6); - oa_tc6_cleanup_ongoing_rx_skb(tc6); + oa_tc6_free_ongoing_skbs(tc6); netdev_err(tc6->netdev, "Device error: %d\n", ret); return ret; } @@ -1146,15 +1175,20 @@ static irqreturn_t oa_tc6_macphy_threaded_irq(int irq, void *data) * no need to attempt spi transfer, once it fails. Pending skbs * are already freed. */ - if (!tc6->disable_traffic) { - while (tc6->int_flag || - (tc6->waiting_tx_skb && tc6->tx_credits)) { - ret = oa_tc6_try_spi_transfer(tc6); - if (ret) { - disable_irq_nosync(tc6->spi->irq); - oa_tc6_disable_traffic(tc6); - break; - } + spin_lock_bh(&tc6->tx_skb_lock); + if (tc6->disable_traffic) { + spin_unlock_bh(&tc6->tx_skb_lock); + return IRQ_HANDLED; + } + spin_unlock_bh(&tc6->tx_skb_lock); + + while (tc6->int_flag || + (tc6->waiting_tx_skb && tc6->tx_credits)) { + ret = oa_tc6_try_spi_transfer(tc6); + if (ret) { + disable_irq_nosync(tc6->spi->irq); + oa_tc6_disable_traffic(tc6); + break; } } @@ -1233,23 +1267,30 @@ EXPORT_SYMBOL_GPL(oa_tc6_zero_align_receive_frame_enable); * @tc6: oa_tc6 struct. * @skb: socket buffer in which the ethernet frame is stored. * - * Return: NETDEV_TX_OK if the transmit ethernet frame skb added in the tx_skb_q - * otherwise returns NETDEV_TX_BUSY. + * Return: NETDEV_TX_OK either on successful queueing of the packet for + * transmission, or on packet getting dropped. Packet can be dropped due to + * failure in linearizing the buffer or disable_traffic is set due to + * earlier fatal error. Returns NETDEV_TX_BUSY when there is no room + * to queue the packet. */ netdev_tx_t oa_tc6_start_xmit(struct oa_tc6 *tc6, struct sk_buff *skb) { - if (tc6->disable_traffic || tc6->waiting_tx_skb) { - netif_stop_queue(tc6->netdev); - return NETDEV_TX_BUSY; - } - if (skb_linearize(skb)) { - dev_kfree_skb_any(skb); - tc6->netdev->stats.tx_dropped++; + oa_tc6_drop_tx_skb(tc6, skb); return NETDEV_TX_OK; } spin_lock_bh(&tc6->tx_skb_lock); + if (tc6->waiting_tx_skb) { + netif_stop_queue(tc6->netdev); + spin_unlock_bh(&tc6->tx_skb_lock); + return NETDEV_TX_BUSY; + } + if (tc6->disable_traffic) { + spin_unlock_bh(&tc6->tx_skb_lock); + oa_tc6_drop_tx_skb(tc6, skb); + return NETDEV_TX_OK; + } tc6->waiting_tx_skb = skb; spin_unlock_bh(&tc6->tx_skb_lock); @@ -1403,8 +1444,10 @@ EXPORT_SYMBOL_GPL(oa_tc6_init); */ void oa_tc6_exit(struct oa_tc6 *tc6) { - tc6->disable_traffic = true; disable_irq(tc6->spi->irq); + spin_lock_bh(&tc6->tx_skb_lock); + tc6->disable_traffic = true; + spin_unlock_bh(&tc6->tx_skb_lock); oa_tc6_phy_exit(tc6); oa_tc6_free_pending_skbs(tc6); } -- 2.53.0