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 A8B9AC46467 for ; Mon, 16 Jan 2023 16:41:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233706AbjAPQlR (ORCPT ); Mon, 16 Jan 2023 11:41:17 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34906 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233663AbjAPQkx (ORCPT ); Mon, 16 Jan 2023 11:40:53 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6B22B27498 for ; Mon, 16 Jan 2023 08:29:06 -0800 (PST) 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 2D47EB80DC7 for ; Mon, 16 Jan 2023 16:29:05 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 81FCBC433F0; Mon, 16 Jan 2023 16:29:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1673886543; bh=D8hXZNR+Dhb8nYIzmUavICNzVyzpGj2VTQ3/lqjfY+U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vTqFf/YoIjXFlonKwbigkPJ50D4SNL/J/lhH74FEPvyDjAbmc38w9JVi4bSqjDf6L miZmG8hNLZaOlMagdpX04L3uXPC1d52jrLmeThLkdsj2wAAKU9Dh1bfRBht9fMl+lr 1GmBRMMqe9ORefZ5aJEy1iv49Gucy7/qhRNSpS34= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Mikulas Patocka , Song Liu Subject: [PATCH 5.4 470/658] md: fix a crash in mempool_free Date: Mon, 16 Jan 2023 16:49:18 +0100 Message-Id: <20230116154930.997436308@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230116154909.645460653@linuxfoundation.org> References: <20230116154909.645460653@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: Mikulas Patocka commit 341097ee53573e06ab9fc675d96a052385b851fa upstream. There's a crash in mempool_free when running the lvm test shell/lvchange-rebuild-raid.sh. The reason for the crash is this: * super_written calls atomic_dec_and_test(&mddev->pending_writes) and wake_up(&mddev->sb_wait). Then it calls rdev_dec_pending(rdev, mddev) and bio_put(bio). * so, the process that waited on sb_wait and that is woken up is racing with bio_put(bio). * if the process wins the race, it calls bioset_exit before bio_put(bio) is executed. * bio_put(bio) attempts to free a bio into a destroyed bio set - causing a crash in mempool_free. We fix this bug by moving bio_put before atomic_dec_and_test. We also move rdev_dec_pending before atomic_dec_and_test as suggested by Neil Brown. The function md_end_flush has a similar bug - we must call bio_put before we decrement the number of in-progress bios. BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 11557f0067 P4D 11557f0067 PUD 0 Oops: 0002 [#1] PREEMPT SMP CPU: 0 PID: 73 Comm: kworker/0:1 Not tainted 6.1.0-rc3 #5 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 Workqueue: kdelayd flush_expired_bios [dm_delay] RIP: 0010:mempool_free+0x47/0x80 Code: 48 89 ef 5b 5d ff e0 f3 c3 48 89 f7 e8 32 45 3f 00 48 63 53 08 48 89 c6 3b 53 04 7d 2d 48 8b 43 10 8d 4a 01 48 89 df 89 4b 08 <48> 89 2c d0 e8 b0 45 3f 00 48 8d 7b 30 5b 5d 31 c9 ba 01 00 00 00 RSP: 0018:ffff88910036bda8 EFLAGS: 00010093 RAX: 0000000000000000 RBX: ffff8891037b65d8 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 0000000000000202 RDI: ffff8891037b65d8 RBP: ffff8891447ba240 R08: 0000000000012908 R09: 00000000003d0900 R10: 0000000000000000 R11: 0000000000173544 R12: ffff889101a14000 R13: ffff8891562ac300 R14: ffff889102b41440 R15: ffffe8ffffa00d05 FS: 0000000000000000(0000) GS:ffff88942fa00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000001102e99000 CR4: 00000000000006b0 Call Trace: clone_endio+0xf4/0x1c0 [dm_mod] clone_endio+0xf4/0x1c0 [dm_mod] __submit_bio+0x76/0x120 submit_bio_noacct_nocheck+0xb6/0x2a0 flush_expired_bios+0x28/0x2f [dm_delay] process_one_work+0x1b4/0x300 worker_thread+0x45/0x3e0 ? rescuer_thread+0x380/0x380 kthread+0xc2/0x100 ? kthread_complete_and_exit+0x20/0x20 ret_from_fork+0x1f/0x30 Modules linked in: brd dm_delay dm_raid dm_mod af_packet uvesafb cfbfillrect cfbimgblt cn cfbcopyarea fb font fbdev tun autofs4 binfmt_misc configfs ipv6 virtio_rng virtio_balloon rng_core virtio_net pcspkr net_failover failover qemu_fw_cfg button mousedev raid10 raid456 libcrc32c async_raid6_recov async_memcpy async_pq raid6_pq async_xor xor async_tx raid1 raid0 md_mod sd_mod t10_pi crc64_rocksoft crc64 virtio_scsi scsi_mod evdev psmouse bsg scsi_common [last unloaded: brd] CR2: 0000000000000000 ---[ end trace 0000000000000000 ]--- Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org Signed-off-by: Song Liu Signed-off-by: Greg Kroah-Hartman --- drivers/md/md.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -481,13 +481,14 @@ static void md_end_flush(struct bio *bio struct md_rdev *rdev = bio->bi_private; struct mddev *mddev = rdev->mddev; + bio_put(bio); + rdev_dec_pending(rdev, mddev); if (atomic_dec_and_test(&mddev->flush_pending)) { /* The pre-request flush has finished */ queue_work(md_wq, &mddev->flush_work); } - bio_put(bio); } static void md_submit_flush_data(struct work_struct *ws); @@ -885,10 +886,12 @@ static void super_written(struct bio *bi } else clear_bit(LastDev, &rdev->flags); + bio_put(bio); + + rdev_dec_pending(rdev, mddev); + if (atomic_dec_and_test(&mddev->pending_writes)) wake_up(&mddev->sb_wait); - rdev_dec_pending(rdev, mddev); - bio_put(bio); } void md_super_write(struct mddev *mddev, struct md_rdev *rdev,