From patchwork Tue Apr 26 08:20:37 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 566634 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 426DCC433F5 for ; Tue, 26 Apr 2022 08:43:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243169AbiDZIqE (ORCPT ); Tue, 26 Apr 2022 04:46:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54922 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345712AbiDZIoE (ORCPT ); Tue, 26 Apr 2022 04:44:04 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8298515C28B; Tue, 26 Apr 2022 01:33:32 -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 dfw.source.kernel.org (Postfix) with ESMTPS id D9C7E617E7; Tue, 26 Apr 2022 08:33:31 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CEB9AC385A0; Tue, 26 Apr 2022 08:33:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1650962011; bh=mnBmWAazVjEStZHeTgNy6ggXL6fufuhNgYje+J996tc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qv0RG40EEbIjZFv4ZrMvJoFhLVpwxjSopgaCPsG1SK2XRRJ1GsydA3Qkn4eT46NOi gpYi/ySqwEbcjlrZHueE+YALk5DaVuvI5vGHzIvgQGXP4D+NeYRWtwicWVl1AkcjyT VtUY0f2MmZB/S8uJk5hwAnOwt8vWy6GHInoATUH4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jiazi Li , Mike Snitzer , Akilesh Kailash Subject: [PATCH 5.10 09/86] dm: fix mempool NULL pointer race when completing IO Date: Tue, 26 Apr 2022 10:20:37 +0200 Message-Id: <20220426081741.477201436@linuxfoundation.org> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220426081741.202366502@linuxfoundation.org> References: <20220426081741.202366502@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jiazi Li commit d208b89401e073de986dc891037c5a668f5d5d95 upstream. 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(). Cc: stable@vger.kernel.org Signed-off-by: Jiazi Li Signed-off-by: Mike Snitzer Signed-off-by: Akilesh Kailash Signed-off-by: Greg Kroah-Hartman --- drivers/md/dm.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -607,18 +607,17 @@ static void start_io_acct(struct dm_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 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 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;