From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 77BD0C0015E for ; Wed, 9 Aug 2023 10:55:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232424AbjHIKzL (ORCPT ); Wed, 9 Aug 2023 06:55:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40224 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230088AbjHIKy7 (ORCPT ); Wed, 9 Aug 2023 06:54:59 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 52A3C2D66 for ; Wed, 9 Aug 2023 03:53:27 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id BDD196312B for ; Wed, 9 Aug 2023 10:52:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CCF39C433C8; Wed, 9 Aug 2023 10:52:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1691578368; bh=AqAh7YCAiUeU0r707uGxMBwKEUx2DmtY4bG0LN6OTqI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZCPGFe6B4wbHu7MPRegeIU5Me1MWAGIfX2tTCZ0oj/Hi2CjDGFGVxkIEhaUv15ftD qNyW1Q+T8eZVbes1xjOhGJVkJafzuyGmeg9y8L2GUNWPpRIWcNNAijgnCxleSu/UR/ a2NpDpf5i2MR2TqA8Ap5LFvoKND13MlSKzruRbZI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Chengfeng Ye , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.1 033/127] mISDN: hfcpci: Fix potential deadlock on &hc->lock Date: Wed, 9 Aug 2023 12:40:20 +0200 Message-ID: <20230809103637.760403953@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230809103636.615294317@linuxfoundation.org> References: <20230809103636.615294317@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Chengfeng Ye [ Upstream commit 56c6be35fcbed54279df0a2c9e60480a61841d6f ] As &hc->lock is acquired by both timer _hfcpci_softirq() and hardirq hfcpci_int(), the timer should disable irq before lock acquisition otherwise deadlock could happen if the timmer is preemtped by the hadr irq. Possible deadlock scenario: hfcpci_softirq() (timer) -> _hfcpci_softirq() -> spin_lock(&hc->lock); -> hfcpci_int() -> spin_lock(&hc->lock); (deadlock here) This flaw was found by an experimental static analysis tool I am developing for irq-related deadlock. The tentative patch fixes the potential deadlock by spin_lock_irq() in timer. Fixes: b36b654a7e82 ("mISDN: Create /sys/class/mISDN") Signed-off-by: Chengfeng Ye Link: https://lore.kernel.org/r/20230727085619.7419-1-dg573847474@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/isdn/hardware/mISDN/hfcpci.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/isdn/hardware/mISDN/hfcpci.c b/drivers/isdn/hardware/mISDN/hfcpci.c index c0331b2680108..fe391de1aba32 100644 --- a/drivers/isdn/hardware/mISDN/hfcpci.c +++ b/drivers/isdn/hardware/mISDN/hfcpci.c @@ -839,7 +839,7 @@ hfcpci_fill_fifo(struct bchannel *bch) *z1t = cpu_to_le16(new_z1); /* now send data */ if (bch->tx_idx < bch->tx_skb->len) return; - dev_kfree_skb(bch->tx_skb); + dev_kfree_skb_any(bch->tx_skb); if (get_next_bframe(bch)) goto next_t_frame; return; @@ -895,7 +895,7 @@ hfcpci_fill_fifo(struct bchannel *bch) } bz->za[new_f1].z1 = cpu_to_le16(new_z1); /* for next buffer */ bz->f1 = new_f1; /* next frame */ - dev_kfree_skb(bch->tx_skb); + dev_kfree_skb_any(bch->tx_skb); get_next_bframe(bch); } @@ -1119,7 +1119,7 @@ tx_birq(struct bchannel *bch) if (bch->tx_skb && bch->tx_idx < bch->tx_skb->len) hfcpci_fill_fifo(bch); else { - dev_kfree_skb(bch->tx_skb); + dev_kfree_skb_any(bch->tx_skb); if (get_next_bframe(bch)) hfcpci_fill_fifo(bch); } @@ -2277,7 +2277,7 @@ _hfcpci_softirq(struct device *dev, void *unused) return 0; if (hc->hw.int_m2 & HFCPCI_IRQ_ENABLE) { - spin_lock(&hc->lock); + spin_lock_irq(&hc->lock); bch = Sel_BCS(hc, hc->hw.bswapped ? 2 : 1); if (bch && bch->state == ISDN_P_B_RAW) { /* B1 rx&tx */ main_rec_hfcpci(bch); @@ -2288,7 +2288,7 @@ _hfcpci_softirq(struct device *dev, void *unused) main_rec_hfcpci(bch); tx_birq(bch); } - spin_unlock(&hc->lock); + spin_unlock_irq(&hc->lock); } return 0; } -- 2.40.1