From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 242B03F9280; Wed, 20 May 2026 17:59:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779299971; cv=none; b=p05vVqFpn0foxjIBDVYWZ6nBMiG8IBO7s1Q3QEF9Sb6GslBfhs/2RCW4xgdSprimgnbHBgzA4BUueWAHTityfH4jVFMGukl0N3fTwbFsUpO+DngSYvGOmGnjcFkZ7pVXz7f4NHoSMhZVTsZs1TvPYS73h2D4Un6XVsgELLnxtfo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779299971; c=relaxed/simple; bh=iIGNTPs0WKPdssxnlcqW6Y18XqlMOAlikoL7oQROiFw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=euuzNiCVl2MzqSrS/akZz9batp1MEE6xfoAo+B/spsAB8PwssMcWjPegKzA+HLfGcXNF+gnpaj35l0OCL/a8VGD1Vb23Ut/ACT17bDDb231TN6ZrL6AL4PB3JkuagQp+ZKiLzy3BM7mBXbRY/DeQl98mSNKivKmeUYopwd0zWGI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=SaFPUx6W; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="SaFPUx6W" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C65EC1F000E9; Wed, 20 May 2026 17:59:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1779299968; bh=GnOW5Xvi3exo8MiPH5PAdeuxUEOfVm9T1SwyP3XWT7A=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=SaFPUx6W0bWuPxoFq/1DUiy98yZaYW2v1OnHbIp+rmIDCdC8xjyB6xssJrjWEHvyX ejA9juQAOSq2sQFzC3pLbhZjoz/zNJimH1whT03HlJcs5soP95MJWe4PjecqLWUF9x 2m+vaYd63NSy9TdSg1JZuD7A/seX5BelY7tiYIwc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable@kernel.org, Shinichiro Kawasaki , Chao Yu , Jaegeuk Kim , Sasha Levin Subject: [PATCH 6.18 955/957] f2fs: fix false alarm of lockdep on cp_global_sem lock Date: Wed, 20 May 2026 18:23:58 +0200 Message-ID: <20260520162155.314094539@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260520162134.554764788@linuxfoundation.org> References: <20260520162134.554764788@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chao Yu [ Upstream commit 6a5e3de9c2bb0b691d16789a5d19e9276a09b308 ] lockdep reported a potential deadlock: a) TCMU device removal context: - call del_gendisk() to get q->q_usage_counter - call start_flush_work() to get work_completion of wb->dwork b) f2fs writeback context: - in wb_workfn(), which holds work_completion of wb->dwork - call f2fs_balance_fs() to get sbi->gc_lock c) f2fs vfs_write context: - call f2fs_gc() to get sbi->gc_lock - call f2fs_write_checkpoint() to get sbi->cp_global_sem d) f2fs mount context: - call recover_fsync_data() to get sbi->cp_global_sem - call f2fs_check_and_fix_write_pointer() to call blkdev_report_zones() that goes down to blk_mq_alloc_request and get q->q_usage_counter Original callstack is in Closes tag. However, I think this is a false alarm due to before mount returns successfully (context d), we can not access file therein via vfs_write (context c). Let's introduce per-sb cp_global_sem_key, and assign the key for cp_global_sem, so that lockdep can recognize cp_global_sem from different super block correctly. A lot of work are done by Shin'ichiro Kawasaki, thanks a lot for the work. Fixes: c426d99127b1 ("f2fs: Check write pointer consistency of open zones") Cc: stable@kernel.org Reported-and-tested-by: Shin'ichiro Kawasaki Closes: https://lore.kernel.org/linux-f2fs-devel/20260218125237.3340441-1-shinichiro.kawasaki@wdc.com Signed-off-by: Shin'ichiro Kawasaki Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim [ adapted context to use plain `init_f2fs_rwsem` instead of mainline's `init_f2fs_rwsem_trace` macro ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- fs/f2fs/f2fs.h | 3 +++ fs/f2fs/super.c | 11 +++++++++++ 2 files changed, 14 insertions(+) --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -1967,6 +1967,9 @@ struct f2fs_sb_info { spinlock_t iostat_lat_lock; struct iostat_lat_info *iostat_io_lat; #endif +#ifdef CONFIG_DEBUG_LOCK_ALLOC + struct lock_class_key cp_global_sem_key; +#endif }; /* Definitions to access f2fs_sb_info */ --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -4889,6 +4889,11 @@ try_onemore: init_f2fs_rwsem(&sbi->gc_lock); mutex_init(&sbi->writepages); init_f2fs_rwsem(&sbi->cp_global_sem); +#ifdef CONFIG_DEBUG_LOCK_ALLOC + lockdep_register_key(&sbi->cp_global_sem_key); + lockdep_set_class(&sbi->cp_global_sem.internal_rwsem, + &sbi->cp_global_sem_key); +#endif init_f2fs_rwsem(&sbi->node_write); init_f2fs_rwsem(&sbi->node_change); spin_lock_init(&sbi->stat_lock); @@ -5360,6 +5365,9 @@ free_options: free_sb_buf: kfree(raw_super); free_sbi: +#ifdef CONFIG_DEBUG_LOCK_ALLOC + lockdep_unregister_key(&sbi->cp_global_sem_key); +#endif kfree(sbi); sb->s_fs_info = NULL; @@ -5441,6 +5449,9 @@ static void kill_f2fs_super(struct super /* Release block devices last, after fscrypt_destroy_keyring(). */ if (sbi) { destroy_device_list(sbi); +#ifdef CONFIG_DEBUG_LOCK_ALLOC + lockdep_unregister_key(&sbi->cp_global_sem_key); +#endif kfree(sbi); sb->s_fs_info = NULL; }