From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 1476E21C9F2 for ; Thu, 8 May 2025 06:41:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746686468; cv=none; b=FPqKe4hry7iwSY1etVbfP349cb6BUV/tJXPwlVGSdLCwXVvHRZ7wZ4VjXCxOBf3NYzE7oBE6jmaIMgufJtfv4Nazy8Wvyr1yTqYxjkCCZe3uvrV2lPEpdrHQ1T/UrRAAgDZ+E942xX3YwfjKOs7JW1PF1XiGSehwF/54UjAZgBs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746686468; c=relaxed/simple; bh=wxcEFMvUtB5nrd8bEdVgNg8csOQgGxGzlz+tvRlJhQc=; h=Date:To:From:Subject:Message-Id; b=pNpkju5iU98nSI5pjdkkW1h+VSJqiBHygAeivyiFivDQj0c6+yN5htrHCTveiCihkzNNXw3b8Iw3oDe2KTAi2HXXmVrOLNxqQUUxD4JZ/OPLKda3MLqkOyKb0WbqxQ7T3Df1FqZ2haz8RzcMJQGnNxiHnXX2pgiZg/PxSOEH7Pc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=k1LPOkmc; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="k1LPOkmc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DD39BC4CEEF; Thu, 8 May 2025 06:41:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1746686467; bh=wxcEFMvUtB5nrd8bEdVgNg8csOQgGxGzlz+tvRlJhQc=; h=Date:To:From:Subject:From; b=k1LPOkmcUIaS3Ve7UxXoMfbMUyLyX9acJli0BDMt3m7fXD5DlXR+u6P7FIdP6FAl0 jx2N7KJvLabIQFhLBA9hChIktMGEYupHyMHPCA5mLO1pxKK08X8/tl2eneVLW7iTtB 4ysk9jiH/pl4wUAwM/V0FeR2Fx28PA06wptu3c8Y= Date: Wed, 07 May 2025 23:41:07 -0700 To: mm-commits@vger.kernel.org,konishi.ryusuke@gmail.com,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-hotfixes-stable] nilfs2-fix-deadlock-warnings-caused-by-lock-dependency-in-init_nilfs.patch removed from -mm tree Message-Id: <20250508064107.DD39BC4CEEF@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: nilfs2: fix deadlock warnings caused by lock dependency in init_nilfs() has been removed from the -mm tree. Its filename was nilfs2-fix-deadlock-warnings-caused-by-lock-dependency-in-init_nilfs.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Ryusuke Konishi Subject: nilfs2: fix deadlock warnings caused by lock dependency in init_nilfs() Date: Sat, 3 May 2025 14:33:14 +0900 After commit c0e473a0d226 ("block: fix race between set_blocksize and read paths") was merged, set_blocksize() called by sb_set_blocksize() now locks the inode of the backing device file. As a result of this change, syzbot started reporting deadlock warnings due to a circular dependency involving the semaphore "ns_sem" of the nilfs object, the inode lock of the backing device file, and the locks that this inode lock is transitively dependent on. This is caused by a new lock dependency added by the above change, since init_nilfs() calls sb_set_blocksize() in the lock section of "ns_sem". However, these warnings are false positives because init_nilfs() is called in the early stage of the mount operation and the filesystem has not yet started. The reason why "ns_sem" is locked in init_nilfs() was to avoid a race condition in nilfs_fill_super() caused by sharing a nilfs object among multiple filesystem instances (super block structures) in the early implementation. However, nilfs objects and super block structures have long ago become one-to-one, and there is no longer any need to use the semaphore there. So, fix this issue by removing the use of the semaphore "ns_sem" in init_nilfs(). Link: https://lkml.kernel.org/r/20250503053327.12294-1-konishi.ryusuke@gmail.com Fixes: c0e473a0d226 ("block: fix race between set_blocksize and read paths") Signed-off-by: Ryusuke Konishi Reported-by: syzbot+00f7f5b884b117ee6773@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=00f7f5b884b117ee6773 Tested-by: syzbot+00f7f5b884b117ee6773@syzkaller.appspotmail.com Reported-by: syzbot+f30591e72bfc24d4715b@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=f30591e72bfc24d4715b Tested-by: syzbot+f30591e72bfc24d4715b@syzkaller.appspotmail.com> Signed-off-by: Andrew Morton --- fs/nilfs2/the_nilfs.c | 3 --- 1 file changed, 3 deletions(-) --- a/fs/nilfs2/the_nilfs.c~nilfs2-fix-deadlock-warnings-caused-by-lock-dependency-in-init_nilfs +++ a/fs/nilfs2/the_nilfs.c @@ -705,8 +705,6 @@ int init_nilfs(struct the_nilfs *nilfs, int blocksize; int err; - down_write(&nilfs->ns_sem); - blocksize = sb_min_blocksize(sb, NILFS_MIN_BLOCK_SIZE); if (!blocksize) { nilfs_err(sb, "unable to set blocksize"); @@ -779,7 +777,6 @@ int init_nilfs(struct the_nilfs *nilfs, set_nilfs_init(nilfs); err = 0; out: - up_write(&nilfs->ns_sem); return err; failed_sbh: _ Patches currently in -mm which might be from konishi.ryusuke@gmail.com are nilfs2-do-not-propagate-enoent-error-from-nilfs_btree_propagate.patch