From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-io1-f79.google.com (mail-io1-f79.google.com [209.85.166.79]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C4BDF27CB10 for ; Tue, 22 Apr 2025 12:11:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.166.79 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745323890; cv=none; b=lqRCfeXu1OwsGjA1gZqkXrOZRCUHNpIEgx4d4XEFYgd9EcqCA9oR8PM96xOw0GIK8IN+zEAkLtEv5fLPPbth+R/uQrZOmL1bOgxbUOdBAPJEmUUgk0L/dlAdAY8WHNDvLFWw55iK9d9K9Jk2XIeDH0Sqk8d25/4DcefXTf0uhxk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745323890; c=relaxed/simple; bh=v+QGk9aZpsAsGScTaJ03a6+SiReqDBbzR8DgGCECRiM=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=DXt4t4S8h1hiVEawBQvrPgBK+tLTZZ1tX+doLY5fqOhBJseQv9B1IYd/6SSjJmdAajE9R0TGQOp+02FeShmYEKZnAEBU3CWedgWg7761N1PIAxsHcmowEGzivQ2nU59fJeGIkSuw0PpwgO1B/My9goviKutUwcJCbF+9ABaH/ms= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.166.79 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-io1-f79.google.com with SMTP id ca18e2360f4ac-85b5a7981ccso504494639f.2 for ; Tue, 22 Apr 2025 05:11:28 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1745323888; x=1745928688; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=msWtidcZBgXXJ+183U0Y5v1GiY5Yg9JwQ4JAAakzZbI=; b=QqM+UfOnA+Ppmq4JHAOUwRpsl5deguJpkgbcVP582Thx0pHY9jDCK1hgBAe/PkEurn VAVA/Knt8xWQfWYv345YCPAXgO27GnwXor3nUNBGjHGz7N4ZaxZ1HJdKc+lUI8F2slDw 8evB5sQwPsvtPw09gfA7auYzxqmEFMxtf8HYSq7/JZi7cQMefwkxh26lcsO37cQHXpL8 D6rcgc5X0h43tYffz0fxNslt4DLAwgLR/Rl52k8dHDuRf8JW/yQvvvZ03vz29SjiHUYX 3F1ofyePLKi/b8addzH2KKdWWecuZNfKnwJ9sPYySW8bMg+vjro6UM4v/Iyx8FbULQOl sGuQ== X-Forwarded-Encrypted: i=1; AJvYcCWr7PpV/SM8DY+RaPy+6DcakiN6QX8AymCB7paApW4fQDZwyGoJqnclztNFRvOS6Mejxvbyvm3EuJSiB5dq@vger.kernel.org X-Gm-Message-State: AOJu0YyhP5KVhWuqdmwpZQL0lsff24f2Cc+ZNgKUNZF6xBvU/l52Fu8b UoGPtg6wZRFv6AFHb/M+QJlYTp600IqhuhW8UTZwtM1vvNOB7Dj+HsENn2zHjgiOKv3UWlsIvzK y7sG81SsaQKq+Wg3Yue8mgENV5W3hvrvPYmxHn+dmz5H4H23IPn419qo= X-Google-Smtp-Source: AGHT+IEMFb8JU/M7kVuJoJS8TIxiLrbjAhQDbP3f3uGhmZLC41LA0ZmwIkm5GudqZ0a7Imt9SF7LapTDu37yzsZXoBtStblPMwSL Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6e02:4417:10b0:3d9:24d8:8d4f with SMTP id e9e14a558f8ab-3d924d88fb1mr4028095ab.16.1745323887958; Tue, 22 Apr 2025 05:11:27 -0700 (PDT) Date: Tue, 22 Apr 2025 05:11:27 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6807876f.050a0220.8500a.000f.GAE@google.com> Subject: [syzbot] [fs?] KCSAN: data-race in choose_mountpoint_rcu / umount_tree From: syzbot To: brauner@kernel.org, jack@suse.cz, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: a33b5a08cbbd Merge tag 'sched_ext-for-6.15-rc3-fixes' of g.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1058f26f980000 kernel config: https://syzkaller.appspot.com/x/.config?x=85dd0f8b81b9d41f dashboard link: https://syzkaller.appspot.com/bug?extid=81fdaf0f522d5c5e41fb compiler: Debian clang version 15.0.6, Debian LLD 15.0.6 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/718e6f7bde0a/disk-a33b5a08.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/20f5e402fb15/vmlinux-a33b5a08.xz kernel image: https://storage.googleapis.com/syzbot-assets/2dd06e277fc7/bzImage-a33b5a08.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+81fdaf0f522d5c5e41fb@syzkaller.appspotmail.com ================================================================== BUG: KCSAN: data-race in choose_mountpoint_rcu / umount_tree write to 0xffff888108512d98 of 8 bytes by task 21705 on cpu 1: unhash_mnt fs/namespace.c:1050 [inline] umount_mnt fs/namespace.c:1064 [inline] umount_tree+0x6f0/0xb10 fs/namespace.c:1922 do_umount fs/namespace.c:-1 [inline] path_umount+0x9c1/0xa40 fs/namespace.c:2144 ksys_umount fs/namespace.c:2167 [inline] __do_sys_umount fs/namespace.c:2172 [inline] __se_sys_umount fs/namespace.c:2170 [inline] __x64_sys_umount+0xb7/0xe0 fs/namespace.c:2170 x64_sys_call+0x2883/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:167 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xc9/0x1a0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffff888108512d98 of 8 bytes by task 21704 on cpu 0: choose_mountpoint_rcu+0x3d/0x130 fs/namei.c:1386 follow_dotdot_rcu fs/namei.c:2020 [inline] handle_dots+0x559/0x790 fs/namei.c:2095 walk_component fs/namei.c:2132 [inline] link_path_walk+0x5f6/0x840 fs/namei.c:2503 path_lookupat+0x6c/0x2a0 fs/namei.c:2659 filename_lookup+0x14b/0x340 fs/namei.c:2689 filename_setxattr+0x59/0x2b0 fs/xattr.c:660 path_setxattrat+0x28a/0x320 fs/xattr.c:713 __do_sys_setxattr fs/xattr.c:747 [inline] __se_sys_setxattr fs/xattr.c:743 [inline] __x64_sys_setxattr+0x6e/0x90 fs/xattr.c:743 x64_sys_call+0x28e7/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:189 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xc9/0x1a0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f value changed: 0xffff888116147cc0 -> 0xffff8881065c23c0 Reported by Kernel Concurrency Sanitizer on: CPU: 0 UID: 0 PID: 21704 Comm: syz.6.5865 Not tainted 6.15.0-rc3-syzkaller-00008-ga33b5a08cbbd #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 ================================================================== --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup