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 9D5EEEB64D9 for ; Mon, 19 Jun 2023 11:03:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232284AbjFSLDX (ORCPT ); Mon, 19 Jun 2023 07:03:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33484 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230271AbjFSLCq (ORCPT ); Mon, 19 Jun 2023 07:02:46 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2E1ED19B6 for ; Mon, 19 Jun 2023 04:01:52 -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 763A960B7F for ; Mon, 19 Jun 2023 11:01:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8A2C6C433C0; Mon, 19 Jun 2023 11:01:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1687172510; bh=ERqVmWdpMJU1thQQ/nOlfnOZhQz6BrPisq2C5hvVqrM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CD0IRstvdjPN0+QtMAFi+a3yw6FSSgXr8uJaH2Iy46bwtW7KWBZdtgY5ErcGPhjQk vOBKfcEEGUY5XUfqhDxQYrgX79vpWqUhPNFb3KCXc6apOUFrdFlZVd2ezSXy61kjCJ 8pSK42zzUdNbN4WUNH9zToU+U4ylVOXyLM0EPDck= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Li Lingfeng , Mike Snitzer , Sasha Levin Subject: [PATCH 5.15 095/107] dm: dont lock fs when the map is NULL during suspend or resume Date: Mon, 19 Jun 2023 12:31:19 +0200 Message-ID: <20230619102145.895702780@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230619102141.541044823@linuxfoundation.org> References: <20230619102141.541044823@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: Li Lingfeng [ Upstream commit 2760904d895279f87196f0fa9ec570c79fe6a2e4 ] As described in commit 38d11da522aa ("dm: don't lock fs when the map is NULL in process of resume"), a deadlock may be triggered between do_resume() and do_mount(). This commit preserves the fix from commit 38d11da522aa but moves it to where it also serves to fix a similar deadlock between do_suspend() and do_mount(). It does so, if the active map is NULL, by clearing DM_SUSPEND_LOCKFS_FLAG in dm_suspend() which is called by both do_suspend() and do_resume(). Fixes: 38d11da522aa ("dm: don't lock fs when the map is NULL in process of resume") Signed-off-by: Li Lingfeng Signed-off-by: Mike Snitzer Signed-off-by: Sasha Levin --- drivers/md/dm-ioctl.c | 5 +---- drivers/md/dm.c | 4 ++++ 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c index 438c0b77bb48c..815c41e1ebdb8 100644 --- a/drivers/md/dm-ioctl.c +++ b/drivers/md/dm-ioctl.c @@ -1145,13 +1145,10 @@ static int do_resume(struct dm_ioctl *param) /* Do we need to load a new map ? */ if (new_map) { sector_t old_size, new_size; - int srcu_idx; /* Suspend if it isn't already suspended */ - old_map = dm_get_live_table(md, &srcu_idx); - if ((param->flags & DM_SKIP_LOCKFS_FLAG) || !old_map) + if (param->flags & DM_SKIP_LOCKFS_FLAG) suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG; - dm_put_live_table(md, srcu_idx); if (param->flags & DM_NOFLUSH_FLAG) suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG; if (!dm_suspended_md(md)) diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 8bc121d394471..d6285a23dc3ed 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -2526,6 +2526,10 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags) } map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock)); + if (!map) { + /* avoid deadlock with fs/namespace.c:do_mount() */ + suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG; + } r = __dm_suspend(md, map, suspend_flags, TASK_INTERRUPTIBLE, DMF_SUSPENDED); if (r) -- 2.39.2