From nobody Mon Sep 29 22:44:53 2025 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 75480C25B0D for ; Tue, 16 Aug 2022 04:31:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229991AbiHPEbH (ORCPT ); Tue, 16 Aug 2022 00:31:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44236 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229725AbiHPEag (ORCPT ); Tue, 16 Aug 2022 00:30:36 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 37D0515CE2C; Mon, 15 Aug 2022 13:18:21 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 5D1A7B81136; Mon, 15 Aug 2022 20:18:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8B723C433D6; Mon, 15 Aug 2022 20:18:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1660594690; bh=ugN1MXcCApqALg9q87upT46qcpdfkj7zJELzLfbEAFI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kRFr5rfv1ohFX+XVBhaHCL1Wlfze8RkANP8VPfkkJI1Skan1p/nuFeMgQLCyalOba HdHYUx0FhR0VoIqIIyZVvkzepvnPoRPpUmi6I7LZ8LerCz9gSZjAhPCKPnTgtb9DPV tXI5FH28412pKG0yZEPGv2mpgUF88NTUBv28efBc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+63bed493aebbf6872647@syzkaller.appspotmail.com, Schspa Shi , Marcel Holtmann , Sasha Levin Subject: [PATCH 5.19 0528/1157] Bluetooth: When HCI work queue is drained, only queue chained work Date: Mon, 15 Aug 2022 19:58:04 +0200 Message-Id: <20220815180500.780472691@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220815180439.416659447@linuxfoundation.org> References: <20220815180439.416659447@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Schspa Shi [ Upstream commit 877afadad2dce8aae1f2aad8ce47e072d4f6165e ] The HCI command, event, and data packet processing workqueue is drained to avoid deadlock in commit 76727c02c1e1 ("Bluetooth: Call drain_workqueue() before resetting state"). There is another delayed work, which will queue command to this drained workqueue. Which results in the following error report: Bluetooth: hci2: command 0x040f tx timeout WARNING: CPU: 1 PID: 18374 at kernel/workqueue.c:1438 __queue_work+0xdad/0x= 1140 Workqueue: events hci_cmd_timeout RIP: 0010:__queue_work+0xdad/0x1140 RSP: 0000:ffffc90002cffc60 EFLAGS: 00010093 RAX: 0000000000000000 RBX: ffff8880b9d3ec00 RCX: 0000000000000000 RDX: ffff888024ba0000 RSI: ffffffff814e048d RDI: ffff8880b9d3ec08 RBP: 0000000000000008 R08: 0000000000000000 R09: 00000000b9d39700 R10: ffffffff814f73c6 R11: 0000000000000000 R12: ffff88807cce4c60 R13: 0000000000000000 R14: ffff8880796d8800 R15: ffff8880796d8800 FS: 0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c0174b4000 CR3: 000000007cae9000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ? queue_work_on+0xcb/0x110 ? lockdep_hardirqs_off+0x90/0xd0 queue_work_on+0xee/0x110 process_one_work+0x996/0x1610 ? pwq_dec_nr_in_flight+0x2a0/0x2a0 ? rwlock_bug.part.0+0x90/0x90 ? _raw_spin_lock_irq+0x41/0x50 worker_thread+0x665/0x1080 ? process_one_work+0x1610/0x1610 kthread+0x2e9/0x3a0 ? kthread_complete_and_exit+0x40/0x40 ret_from_fork+0x1f/0x30 To fix this, we can add a new HCI_DRAIN_WQ flag, and don't queue the timeout workqueue while command workqueue is draining. Fixes: 76727c02c1e1 ("Bluetooth: Call drain_workqueue() before resetting st= ate") Reported-by: syzbot+63bed493aebbf6872647@syzkaller.appspotmail.com Signed-off-by: Schspa Shi Signed-off-by: Marcel Holtmann Signed-off-by: Sasha Levin --- include/net/bluetooth/hci.h | 1 + net/bluetooth/hci_core.c | 10 +++++++++- net/bluetooth/hci_event.c | 5 +++-- 3 files changed, 13 insertions(+), 3 deletions(-) diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h index fe7935be7dc4..4a45c48eb0d2 100644 --- a/include/net/bluetooth/hci.h +++ b/include/net/bluetooth/hci.h @@ -361,6 +361,7 @@ enum { HCI_QUALITY_REPORT, HCI_OFFLOAD_CODECS_ENABLED, HCI_LE_SIMULTANEOUS_ROLES, + HCI_CMD_DRAIN_WORKQUEUE, =20 __HCI_NUM_FLAGS, }; diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c index a0f99baafd35..6a53bcc5cfbb 100644 --- a/net/bluetooth/hci_core.c +++ b/net/bluetooth/hci_core.c @@ -594,6 +594,11 @@ static int hci_dev_do_reset(struct hci_dev *hdev) skb_queue_purge(&hdev->rx_q); skb_queue_purge(&hdev->cmd_q); =20 + /* Cancel these to avoid queueing non-chained pending work */ + hci_dev_set_flag(hdev, HCI_CMD_DRAIN_WORKQUEUE); + cancel_delayed_work(&hdev->cmd_timer); + cancel_delayed_work(&hdev->ncmd_timer); + /* Avoid potential lockdep warnings from the *_flush() calls by * ensuring the workqueue is empty up front. */ @@ -607,6 +612,8 @@ static int hci_dev_do_reset(struct hci_dev *hdev) if (hdev->flush) hdev->flush(hdev); =20 + hci_dev_clear_flag(hdev, HCI_CMD_DRAIN_WORKQUEUE); + atomic_set(&hdev->cmd_cnt, 1); hdev->acl_cnt =3D 0; hdev->sco_cnt =3D 0; hdev->le_cnt =3D 0; =20 @@ -3864,7 +3871,8 @@ static void hci_cmd_work(struct work_struct *work) if (res < 0) __hci_cmd_sync_cancel(hdev, -res); =20 - if (test_bit(HCI_RESET, &hdev->flags)) + if (test_bit(HCI_RESET, &hdev->flags) || + hci_dev_test_flag(hdev, HCI_CMD_DRAIN_WORKQUEUE)) cancel_delayed_work(&hdev->cmd_timer); else schedule_delayed_work(&hdev->cmd_timer, diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c index af17dfb20e01..7cb956d3abb2 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -3768,8 +3768,9 @@ static inline void handle_cmd_cnt_and_timer(struct hc= i_dev *hdev, u8 ncmd) cancel_delayed_work(&hdev->ncmd_timer); atomic_set(&hdev->cmd_cnt, 1); } else { - schedule_delayed_work(&hdev->ncmd_timer, - HCI_NCMD_TIMEOUT); + if (!hci_dev_test_flag(hdev, HCI_CMD_DRAIN_WORKQUEUE)) + schedule_delayed_work(&hdev->ncmd_timer, + HCI_NCMD_TIMEOUT); } } } --=20 2.35.1