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 77140273D9A; Tue, 21 Oct 2025 19:56:08 +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=1761076569; cv=none; b=WV64DLv+6ulubNdvQ/Gj0aslc68HHM8yOBlZMrVpWY3uB0xE5aAiuk4yiu/+784g++Lmy8NQwO/MILyXv0CG6uNfTNaRFe8AIYBhRgWm7nCJPvdI2zYTYmh4T/msiRg2vYxUVRGKQK8R/mUdhX50nlD7cH7Zc6dSqQu5l659KRk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761076569; c=relaxed/simple; bh=Urn2mIWtIepZa1EMWXkhAISoumLFKyv2avl0g9LL0Kc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=E067936m45zknnQEif11ddXPrOFlW3jWwfxCt0fDbh6xWJuPDCAYLS8utFMgG+Ck/v7dCK402fhzEaMDQpGaYYZhIHpJ9IyJPShcIXRJ0wxGjlHtRlLucErYQ/SMO0dxRudE6q1sr6iWM58VZ5dY77/TKXUo+5Sva0HgEoBL270= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=hVZ1L3MG; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="hVZ1L3MG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 71020C4CEF7; Tue, 21 Oct 2025 19:56:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1761076568; bh=Urn2mIWtIepZa1EMWXkhAISoumLFKyv2avl0g9LL0Kc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hVZ1L3MGYKpbVmEIr5eiNd5c5oz4YLuuXEdfLREtz9LPv0eV4tBA5X7Q5W0FAuKeU BwoTF1v7cSiGConp+7hhX9rcv3ZYcuM2NuUZ0xwqP+2L8EMIvCmpJuw3pPWhGT4pLN lu1cIZ1TirfG4Zj5hq8MvkevzCyN/aQ+M5w/FFLM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ryusuke Konishi , syzbot+00f7f5b884b117ee6773@syzkaller.appspotmail.com, syzbot+f30591e72bfc24d4715b@syzkaller.appspotmail.com, Andrew Morton , Mahmoud Adam Subject: [PATCH 6.6 075/105] nilfs2: fix deadlock warnings caused by lock dependency in init_nilfs() Date: Tue, 21 Oct 2025 21:51:24 +0200 Message-ID: <20251021195023.435485008@linuxfoundation.org> X-Mailer: git-send-email 2.51.1 In-Reply-To: <20251021195021.492915002@linuxfoundation.org> References: <20251021195021.492915002@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ 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 Signed-off-by: Greg Kroah-Hartman --- fs/nilfs2/the_nilfs.c | 3 --- 1 file changed, 3 deletions(-) --- a/fs/nilfs2/the_nilfs.c +++ b/fs/nilfs2/the_nilfs.c @@ -680,8 +680,6 @@ 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"); @@ -757,7 +755,6 @@ int init_nilfs(struct the_nilfs *nilfs, set_nilfs_init(nilfs); err = 0; out: - up_write(&nilfs->ns_sem); return err; failed_sbh: