From patchwork Mon Apr 25 08:28:12 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Akilesh Kailash X-Patchwork-Id: 568062 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 57E01C433F5 for ; Mon, 25 Apr 2022 08:29:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236072AbiDYIcC (ORCPT ); Mon, 25 Apr 2022 04:32:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41900 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236081AbiDYIb6 (ORCPT ); Mon, 25 Apr 2022 04:31:58 -0400 Received: from mail-pf1-x44a.google.com (mail-pf1-x44a.google.com [IPv6:2607:f8b0:4864:20::44a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D204BC09 for ; Mon, 25 Apr 2022 01:28:42 -0700 (PDT) Received: by mail-pf1-x44a.google.com with SMTP id j17-20020a62b611000000b004fa6338bd77so9959602pff.10 for ; Mon, 25 Apr 2022 01:28:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:message-id:mime-version:subject:from:to:cc; bh=L/g0bvSDwPnuo+OUPLoiHehwSXqnnWuBcck3d5mIN9M=; b=cnmFwoBhFMB/Pj/JIIygENpMidH6zwJmMLX6saPKUkj4UfmSBcYcURpXfcx4gh0inc sGZPs+knBgI3q2bvF9mEN7Vx9W+f2j3iDa3DZAM6Zzizi5icpiqjcEcOTTAjvStdreo0 Jvx2MZr9ym5NsVoKonEl5qY48yp2+2b17c0l1ZNl+AAsS0AnmHtyCZiJA9WGThlJPYQf 4QK34skauRX2AWq4V2e8JZXvXSjj4PqEerFmLDNl+JB6+QXJQO/0BtAVW5HEmFTMtbp4 Fr+1/ojsE4w0nSa04jFOz8XLzyukFF4neklb0jEnDN2qURW+S9hsqE2uoUtyZfjlruAh SmKw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=L/g0bvSDwPnuo+OUPLoiHehwSXqnnWuBcck3d5mIN9M=; b=wuaNx5XUy+wQrHlpx1p3svFrWNB4JFgOi1XiRtNDDZOxGlzYXx4cFYN81x+BP2iZ0P fVX43BwoJiYDI9ZWPFFvgeEdCQcFMLukWWIWS0fgfcoTXUMRVBKirskoNo3TnT1Ul6T1 JcWlVc2//Cos4S/9sMzc2CKVH9u8qGku2z00mXR043q4twMf8rbL61mO1vbkkGBltElV iL1k2CnQvDgl49FP5e2U6iwXbWQXcrEKHijtifSa7KieBT5nQt7GQCrTGpjamqlKm2KS Y3HNywn4h/+b7My7BdPG6qd+c+nsSGQWuqecr2F2etliM0ary+yPu//DoOm5SJMx4JwI fZWw== X-Gm-Message-State: AOAM530JHmip8XjsS4PX9rjnzo+TnOwAaStI+CMOlTLiFBjnmiHXMv4f xoPRE/QbUsevq0lDd/vjqWywHMaw3TciCwl3f9BM5aJrGorLBgzjoYJRVfiS1kNJw0fc7+Sj541 PITF771LLYzVLyDhc8MUG9qFqTADCXKEi7VEF8J9JRWj94swAmqNotP20jRHQOTNjc7Y= X-Google-Smtp-Source: ABdhPJyKgd+B7+akN68eNfEFu0f3pvv3Z+LsqgdmFH8KOvoxR3ca0S+m9ezFTKUSUtq6v9lB4HUsrAun1Ogpng== X-Received: from akailash.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:1e6]) (user=akailash job=sendgmr) by 2002:a17:90a:9105:b0:1d2:9e98:7e1e with SMTP id k5-20020a17090a910500b001d29e987e1emr1365096pjo.0.1650875321248; Mon, 25 Apr 2022 01:28:41 -0700 (PDT) Date: Mon, 25 Apr 2022 08:28:12 +0000 Message-Id: <20220425082812.780445-1-akailash@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.36.0.rc2.479.g8af0fa9b8e-goog Subject: [PATCH] dm: fix mempool NULL pointer race when completing IO From: Akilesh Kailash To: stable@vger.kernel.org Cc: Jiazi Li , kernel-team@android.com, akailash@google.com, Jiazi Li , Mike Snitzer , Alasdair Kergon , dm-devel@redhat.com, linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jiazi Li commit d208b89401e073de986dc891037c5a668f5d5d95 upstream. This is a backport of the upstream patch to 5.10.y stable branch. This backport resolves a minor merge-conflict on 5.10.y stable branch. dm_io_dec_pending() calls end_io_acct() first and will then dec md in-flight pending count. But if a task is swapping DM table at same time this can result in a crash due to mempool->elements being NULL: task1 task2 do_resume ->do_suspend ->dm_wait_for_completion bio_endio ->clone_endio ->dm_io_dec_pending ->end_io_acct ->wakeup task1 ->dm_swap_table ->__bind ->__bind_mempools ->bioset_exit ->mempool_exit ->free_io [ 67.330330] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 ...... [ 67.330494] pstate: 80400085 (Nzcv daIf +PAN -UAO) [ 67.330510] pc : mempool_free+0x70/0xa0 [ 67.330515] lr : mempool_free+0x4c/0xa0 [ 67.330520] sp : ffffff8008013b20 [ 67.330524] x29: ffffff8008013b20 x28: 0000000000000004 [ 67.330530] x27: ffffffa8c2ff40a0 x26: 00000000ffff1cc8 [ 67.330535] x25: 0000000000000000 x24: ffffffdada34c800 [ 67.330541] x23: 0000000000000000 x22: ffffffdada34c800 [ 67.330547] x21: 00000000ffff1cc8 x20: ffffffd9a1304d80 [ 67.330552] x19: ffffffdada34c970 x18: 000000b312625d9c [ 67.330558] x17: 00000000002dcfbf x16: 00000000000006dd [ 67.330563] x15: 000000000093b41e x14: 0000000000000010 [ 67.330569] x13: 0000000000007f7a x12: 0000000034155555 [ 67.330574] x11: 0000000000000001 x10: 0000000000000001 [ 67.330579] x9 : 0000000000000000 x8 : 0000000000000000 [ 67.330585] x7 : 0000000000000000 x6 : ffffff80148b5c1a [ 67.330590] x5 : ffffff8008013ae0 x4 : 0000000000000001 [ 67.330596] x3 : ffffff80080139c8 x2 : ffffff801083bab8 [ 67.330601] x1 : 0000000000000000 x0 : ffffffdada34c970 [ 67.330609] Call trace: [ 67.330616] mempool_free+0x70/0xa0 [ 67.330627] bio_put+0xf8/0x110 [ 67.330638] dec_pending+0x13c/0x230 [ 67.330644] clone_endio+0x90/0x180 [ 67.330649] bio_endio+0x198/0x1b8 [ 67.330655] dec_pending+0x190/0x230 [ 67.330660] clone_endio+0x90/0x180 [ 67.330665] bio_endio+0x198/0x1b8 [ 67.330673] blk_update_request+0x214/0x428 [ 67.330683] scsi_end_request+0x2c/0x300 [ 67.330688] scsi_io_completion+0xa0/0x710 [ 67.330695] scsi_finish_command+0xd8/0x110 [ 67.330700] scsi_softirq_done+0x114/0x148 [ 67.330708] blk_done_softirq+0x74/0xd0 [ 67.330716] __do_softirq+0x18c/0x374 [ 67.330724] irq_exit+0xb4/0xb8 [ 67.330732] __handle_domain_irq+0x84/0xc0 [ 67.330737] gic_handle_irq+0x148/0x1b0 [ 67.330744] el1_irq+0xe8/0x190 [ 67.330753] lpm_cpuidle_enter+0x4f8/0x538 [ 67.330759] cpuidle_enter_state+0x1fc/0x398 [ 67.330764] cpuidle_enter+0x18/0x20 [ 67.330772] do_idle+0x1b4/0x290 [ 67.330778] cpu_startup_entry+0x20/0x28 [ 67.330786] secondary_start_kernel+0x160/0x170 Fix this by: 1) Establishing pointers to 'struct dm_io' members in dm_io_dec_pending() so that they may be passed into end_io_acct() _after_ free_io() is called. 2) Moving end_io_acct() after free_io(). Link: https://lore.kernel.org/dm-devel/1632916768-22379-1-git-send-email-lijiazi@xiaomi.com/T/#u Cc: stable@vger.kernel.org Signed-off-by: Jiazi Li Signed-off-by: Mike Snitzer Signed-off-by: Akilesh Kailash --- drivers/md/dm.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 2836d44094ab..b3d8d9e0e6f6 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -607,18 +607,17 @@ static void start_io_acct(struct dm_io *io) false, 0, &io->stats_aux); } -static void end_io_acct(struct dm_io *io) +static void end_io_acct(struct mapped_device *md, struct bio *bio, + unsigned long start_time, struct dm_stats_aux *stats_aux) { - struct mapped_device *md = io->md; - struct bio *bio = io->orig_bio; - unsigned long duration = jiffies - io->start_time; + unsigned long duration = jiffies - start_time; - bio_end_io_acct(bio, io->start_time); + bio_end_io_acct(bio, start_time); if (unlikely(dm_stats_used(&md->stats))) dm_stats_account_io(&md->stats, bio_data_dir(bio), bio->bi_iter.bi_sector, bio_sectors(bio), - true, duration, &io->stats_aux); + true, duration, stats_aux); /* nudge anyone waiting on suspend queue */ if (unlikely(wq_has_sleeper(&md->wait))) @@ -903,6 +902,8 @@ static void dec_pending(struct dm_io *io, blk_status_t error) blk_status_t io_error; struct bio *bio; struct mapped_device *md = io->md; + unsigned long start_time = 0; + struct dm_stats_aux stats_aux; /* Push-back supersedes any I/O errors */ if (unlikely(error)) { @@ -929,8 +930,10 @@ static void dec_pending(struct dm_io *io, blk_status_t error) io_error = io->status; bio = io->orig_bio; - end_io_acct(io); + start_time = io->start_time; + stats_aux = io->stats_aux; free_io(md, io); + end_io_acct(md, bio, start_time, &stats_aux); if (io_error == BLK_STS_DM_REQUEUE) return;