From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from fra-out-012.esa.eu-central-1.outbound.mail-perimeter.amazon.com (fra-out-012.esa.eu-central-1.outbound.mail-perimeter.amazon.com [52.57.120.243]) (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 1D4221FECBA; Mon, 20 Oct 2025 12:26:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=52.57.120.243 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760963212; cv=none; b=XiInlTmrKhYQdtlHYnBNnCkyS2aNW7mb9j7DGuLUgjKZDoNvIKYpbtwrkyXKePfz/DXvShgTYVh7yUk/Mt+qprtjcNMlZYLv1NlVJbYLmKybrORBOfM6c2a9iafZBk3b+I+f7PdP/TLdXughdQGQDfAdOQtQPdg8pUGsbzXXVXs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760963212; c=relaxed/simple; bh=Hrml92hO+sHgfm80c2Sv139C3pR2KNsFNCr8GaVC08M=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=pC28zdf9y5w8Ki6Dhn9zXlgE1AcLykQrqoqSQKrHdBG16EIPDNJpicU/cGefp+3sZGVvXxSyLsC7jTcAvjvau7K+AiWLZyCp58+ukg4BkmJ0nWk0KdxRk0vTWLgN7fu46JZ+VLYARymeZbPuUwsR/hrorlDV6L1VqBP5HpuBTyI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.de; spf=pass smtp.mailfrom=amazon.de; dkim=pass (2048-bit key) header.d=amazon.de header.i=@amazon.de header.b=Glxaqv/J; arc=none smtp.client-ip=52.57.120.243 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=amazon.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=amazon.de header.i=@amazon.de header.b="Glxaqv/J" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.de; i=@amazon.de; q=dns/txt; s=amazoncorp2; t=1760963209; x=1792499209; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=kx5jVyu5oZ3p0Hh+shYGjcsfkk0CaJ+y6g0ZOwv4/CM=; b=Glxaqv/J619u1fDLs5cK1mIv0HruYbQmGBCBQ9N3oHjxk2bndUK+C4XC EZnfGb+kAU473vE4vhKl9gqA3PRZUVlZYOUZcntnPX5YLAJCMqzra8IYa 2/tVR5TySM8ZQgDJBjDk6gMI5m28ruv0IbD/drU3hz+yBZu1Ms0K5xYXR UC40iJjzCGm4C8/ivTy+1pNh/BUPK2K4BOlUFPbio5AYeRrBoQCaTIS/G C4haDkHZY7PAhk1FLwEe9UGroshhWrdZ/ggd0m0DAIcgDhJEJ6AHXb4l9 RLwxP3eXxm8RWW5Dd+bTbok/v0wNwHWk3ULLJwRQo6JMG8TFmjMaaDLg6 g==; X-CSE-ConnectionGUID: cKLDWJtZTeawHgQ6jj7fGw== X-CSE-MsgGUID: heQ2jjnfQTiOkX+6fHNqJA== X-IronPort-AV: E=Sophos;i="6.19,242,1754956800"; d="scan'208";a="3774967" Received: from ip-10-6-6-97.eu-central-1.compute.internal (HELO smtpout.naws.eu-central-1.prod.farcaster.email.amazon.dev) ([10.6.6.97]) by internal-fra-out-012.esa.eu-central-1.outbound.mail-perimeter.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Oct 2025 12:26:37 +0000 Received: from EX19MTAEUA001.ant.amazon.com [54.240.197.233:3361] by smtpin.naws.eu-central-1.prod.farcaster.email.amazon.dev [10.0.15.203:2525] with esmtp (Farcaster) id e782b80c-d46d-437f-92e9-d119d216c6f5; Mon, 20 Oct 2025 12:26:37 +0000 (UTC) X-Farcaster-Flow-ID: e782b80c-d46d-437f-92e9-d119d216c6f5 Received: from EX19D013EUB004.ant.amazon.com (10.252.51.92) by EX19MTAEUA001.ant.amazon.com (10.252.50.223) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.20; Mon, 20 Oct 2025 12:26:30 +0000 Received: from dev-dsk-mngyadam-1c-cb3f7548.eu-west-1.amazon.com (10.253.107.175) by EX19D013EUB004.ant.amazon.com (10.252.51.92) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.20; Mon, 20 Oct 2025 12:26:26 +0000 From: Mahmoud Adam To: CC: , , Ryusuke Konishi , , , Andrew Morton , Jens Axboe , Luis Chamberlain , "Darrick J. Wong" , , , Subject: [PATCH 6.6 2/2] nilfs2: fix deadlock warnings caused by lock dependency in init_nilfs() Date: Mon, 20 Oct 2025 14:25:39 +0200 Message-ID: <20251020122541.7227-2-mngyadam@amazon.de> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20251020122541.7227-1-mngyadam@amazon.de> References: <20251020122541.7227-1-mngyadam@amazon.de> Precedence: bulk X-Mailing-List: linux-nilfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: EX19D031UWC003.ant.amazon.com (10.13.139.252) To EX19D013EUB004.ant.amazon.com (10.252.51.92) Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit From: Ryusuke Konishi commit fb881cd7604536b17a1927fb0533f9a6982ffcc5 upstream. 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 Signed-off-by: Mahmoud Adam --- Follow up fix. fs/nilfs2/the_nilfs.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c index be41e26b782469..05fdbbc63e1f5f 100644 --- a/fs/nilfs2/the_nilfs.c +++ b/fs/nilfs2/the_nilfs.c @@ -680,8 +680,6 @@ int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data) 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"); @@ -757,7 +755,6 @@ int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data) set_nilfs_init(nilfs); err = 0; out: - up_write(&nilfs->ns_sem); return err; failed_sbh: -- 2.47.3 Amazon Web Services Development Center Germany GmbH Tamara-Danz-Str. 13 10243 Berlin Geschaeftsfuehrung: Christian Schlaeger Eingetragen am Amtsgericht Charlottenburg unter HRB 257764 B Sitz: Berlin Ust-ID: DE 365 538 597