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 C6615169AD2; Tue, 16 Jun 2026 18:36:17 +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=1781634978; cv=none; b=tcr0lo3RhEZzjQpSbHLHO+rY0ar6UB464YKjaD/6jHu17wdInxs+i1SpFORjcnd6/EDXBk5b1WxGSh/5U/zkxHWPhkC97Ek2gum1A+BM7+AptkmuKm52An0CHk5hcMOlZPA3VEScNZkScxXfBuzxkZr1RVnb3efkCeSqbSyCay8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781634978; c=relaxed/simple; bh=Cob6JLo9Wy97eZ1bPdpE79srGsCdMbFs0A02Kktbq0g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ZEEKWNqQGqzrUBoFN48Y13xGZ+TFhd8Oe1zWVWFt3TWkTaLZU5+Bl73TmeoRTN3lPDOOJQcvPqD7mcI/JFxd++etJvZnE9H2/0U97Bg3C30xUaC2x7qxhXDyuin8Ng4ft3mdlxypLm1uRV6b8hRqtE+198THP/fHIzPv92yuI9o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ydMJAPK+; 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="ydMJAPK+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5453B1F000E9; Tue, 16 Jun 2026 18:36:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1781634977; bh=zsQY21QLSUrDNwgG9IHWwBgFJxscvA70qKbgFR4Nmic=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ydMJAPK+y+Rpep2/kgHqz0M6fTIVZW94eK3UUkzQo7eoGi2bXjtuE6EP3UIwQ6Wgn 656KpucGBrQ70W6Ix4ITsnibefkFhD1NIFRJ9tUR5qyZcBpGx6rZNdIFJEBfuqdqNd evsWXQIyZFKycHfx+zG5aE91cbRmQx+JWr/w2xlE= 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 5.15 334/411] f2fs: fix false alarm of lockdep on cp_global_sem lock Date: Tue, 16 Jun 2026 20:29:32 +0530 Message-ID: <20260616145118.916496425@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260616145100.376842714@linuxfoundation.org> References: <20260616145100.376842714@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 5.15-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 to plain `struct rw_semaphore` (no `f2fs_rwsem` wrapper) and moved success-path `lockdep_unregister_key` from `kill_f2fs_super` to `f2fs_put_super` where sbi is actually freed ] 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 @@ -1798,6 +1798,9 @@ 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 }; struct f2fs_private_dio { --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -1668,6 +1668,9 @@ static void f2fs_put_super(struct super_ #ifdef CONFIG_UNICODE utf8_unload(sb->s_encoding); #endif +#ifdef CONFIG_DEBUG_LOCK_ALLOC + lockdep_unregister_key(&sbi->cp_global_sem_key); +#endif kfree(sbi); } @@ -4123,6 +4126,11 @@ try_onemore: init_rwsem(&sbi->gc_lock); mutex_init(&sbi->writepages); init_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, + &sbi->cp_global_sem_key); +#endif init_rwsem(&sbi->node_write); init_rwsem(&sbi->node_change); @@ -4524,6 +4532,9 @@ free_sb_buf: free_sbi: if (sbi->s_chksum_driver) crypto_free_shash(sbi->s_chksum_driver); +#ifdef CONFIG_DEBUG_LOCK_ALLOC + lockdep_unregister_key(&sbi->cp_global_sem_key); +#endif kfree(sbi); /* give only one another chance */