From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oi1-f206.google.com (mail-oi1-f206.google.com [209.85.167.206]) (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 4F96F43F08C for ; Tue, 28 Jul 2026 13:31:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.206 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785245500; cv=none; b=au1H+d3bpYsSR/4RV1ZIgvm80XP4WG7it/i/QjjKmdBT9z//cUUMgCia4USBYCmUWT2czU97VpLe07g24cKg2S6JNvlgT59RiZSS9zLK69pMEKFe3e3nbCCsiko81ro8J8b+J4FXpoope7DCXUKTH3fb/r3HXbOwnLdrFLccR1Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785245500; c=relaxed/simple; bh=2oFKQj2LOMTsmt4JuBs2TXh8g2RDGarnVWjVeWWwl/0=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=k9rdo7xQv1tQSxWSCnS5mSze1ahmY/Mfbtc+ywlrgIODq/S2BQRWY0pXSLSTntUoPU4gFV/dyfr15xvuA08tW+cWGFC5myWoy1BIZmCQR1CgZz/CipbpTEZhKK9oefAZg0N86X6zotuetRpFwDsq0BTiqeXuszdtGhxIQsWS4SY= 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=209.85.167.206 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-oi1-f206.google.com with SMTP id 5614622812f47-49d4cb3ca23so5059275b6e.3 for ; Tue, 28 Jul 2026 06:31:31 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1785245489; x=1785850289; h=content-type:to:from:subject:message-id:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=fwJ6tc+LoIte3L/2ELtAEEHw4LCIRUhZiYrCpxiXbhY=; b=kWVfox6BoDoO7A4HGWuCTiQkBSvFzPRy2IuW6vJZa4vsm76DhncbNEceQ6tBodO1Fr T2ztQV1lorFhyGzuXmHxFe3zwagPZHl8KHjOaZhMR5Qcm3grE3wVxFUHYTxRzlgNlXtB wlbThTM5wFCZ0PMZtAkHtGIgG2iGDgr/rNGU/6tFet8nRJZpWSbIV7GKdte+qkMwZKBY dmHNfuC7Vw/q231a2SGq+GK3fufURqc/Fkb2HsI+9Ks3iFTsmLazbqm4U5zHk0F/jck0 j1Q9Ft9XJucaeQkrVa+m097fX6RPm1I50vo06HnCX4uDqanTf5PBKCkYtM9LjyizOi65 juNA== X-Forwarded-Encrypted: i=1; AHgh+RqcJ6Bys5XGPIHPKxM2S4LWyJ6SaO9liooERUIYsYyg1GtFUN/o3Q5zwkBgHWLmEJCvg96OA254UgJ/nXcJ@vger.kernel.org X-Gm-Message-State: AOJu0YxjNS6Gh7eOPcx9kVqdW9pfzeh3INuoOGmSIYDEDTsHfHkJuktN bK3hcHhqfZVazHAX7vm4ICj9l/0Tz7Ivs5821H1DyEXJEm9jHZL3Kfvy+VUE4UcRrV7t9ja/Nw9 cE+JJCzKxTT7WrgBx77Ig/T/4X0nA5ZBhQrmW/WsiJpSHD7I1tW9hycaD1Hk= Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6808:192a:b0:495:e1b6:2c5 with SMTP id 5614622812f47-4ad5b964e3dmr1896961b6e.1.1785245489414; Tue, 28 Jul 2026 06:31:29 -0700 (PDT) Date: Tue, 28 Jul 2026 06:31:29 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a68af31.073198cf.94f0f.0048.GAE@google.com> Subject: [syzbot] [fs?] possible deadlock in configfs_rmdir From: syzbot To: a.hindborg@kernel.org, leitao@debian.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 62cc90241548 Merge tag 'mm-hotfixes-stable-2026-07-27-14-1.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=17cbd8c6580000 kernel config: https://syzkaller.appspot.com/x/.config?x=cb17729fb04b1e3a dashboard link: https://syzkaller.appspot.com/bug?extid=c9f9d646b08f3b6032fe compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/727c8b2ee0d6/disk-62cc9024.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/4e2cc8ae0237/vmlinux-62cc9024.xz kernel image: https://storage.googleapis.com/syzbot-assets/beb9a012f168/bzImage-62cc9024.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+c9f9d646b08f3b6032fe@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.7.499/12527 is trying to acquire lock: ffffffff8ef6f200 (gadget_subsys.su_mutex){+.+.}-{4:4}, at: configfs_rmdir+0x5f0/0x950 fs/configfs/dir.c:1556 but task is already holding lock: ffff88803d44d7f8 (&sb->s_type->i_mutex_key#33){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline] ffff88803d44d7f8 (&sb->s_type->i_mutex_key#33){++++}-{4:4}, at: vfs_rmdir+0xf8/0x6b0 fs/namei.c:5366 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&sb->s_type->i_mutex_key#33){++++}-{4:4}: down_write+0x3a/0x50 kernel/locking/rwsem.c:1631 inode_lock include/linux/fs.h:1024 [inline] configfs_depend_item_unlocked+0x153/0x420 fs/configfs/dir.c:1259 usbg_make_tpg+0x1f6/0x590 drivers/usb/gadget/function/f_tcm.c:1686 target_fabric_make_tpg+0xa8/0x6d0 drivers/target/target_core_fabric_configfs.c:939 configfs_mkdir+0x4f6/0x9e0 fs/configfs/dir.c:1360 vfs_mkdir+0x402/0x620 fs/namei.c:5276 filename_mkdirat+0x289/0x520 fs/namei.c:5309 __do_sys_mkdirat fs/namei.c:5330 [inline] __se_sys_mkdirat+0x35/0x150 fs/namei.c:5327 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&opts->dep_lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/rtmutex_api.c:559 [inline] mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:578 tcm_set_name+0x2b/0xd0 drivers/usb/gadget/function/f_tcm.c:2669 function_make+0x1a8/0x360 drivers/usb/gadget/configfs.c:636 configfs_mkdir+0x4f6/0x9e0 fs/configfs/dir.c:1360 vfs_mkdir+0x402/0x620 fs/namei.c:5276 filename_mkdirat+0x289/0x520 fs/namei.c:5309 __do_sys_mkdirat fs/namei.c:5330 [inline] __se_sys_mkdirat+0x35/0x150 fs/namei.c:5327 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (gadget_subsys.su_mutex){+.+.}-{4:4}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x1520/0x2ce0 kernel/locking/lockdep.c:5237 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/rtmutex_api.c:559 [inline] mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:578 configfs_rmdir+0x5f0/0x950 fs/configfs/dir.c:1556 vfs_rmdir+0x3e9/0x6b0 fs/namei.c:5381 filename_rmdir+0x292/0x520 fs/namei.c:5438 __do_sys_rmdir fs/namei.c:5461 [inline] __se_sys_rmdir+0x2e/0x140 fs/namei.c:5458 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: gadget_subsys.su_mutex --> &opts->dep_lock --> &sb->s_type->i_mutex_key#33 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sb->s_type->i_mutex_key#33); lock(&opts->dep_lock); lock(&sb->s_type->i_mutex_key#33); lock(gadget_subsys.su_mutex); *** DEADLOCK *** 3 locks held by syz.7.499/12527: #0: ffff88801d3b4500 (sb_writers#25){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:494 #1: ffff88805de43cf0 (&default_group_class[depth - 1]#2/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1069 [inline] #1: ffff88805de43cf0 (&default_group_class[depth - 1]#2/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2918 [inline] #1: ffff88805de43cf0 (&default_group_class[depth - 1]#2/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2942 [inline] #1: ffff88805de43cf0 (&default_group_class[depth - 1]#2/1){+.+.}-{4:4}, at: filename_rmdir+0x1cd/0x520 fs/namei.c:5431 #2: ffff88803d44d7f8 (&sb->s_type->i_mutex_key#33){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline] #2: ffff88803d44d7f8 (&sb->s_type->i_mutex_key#33){++++}-{4:4}, at: vfs_rmdir+0xf8/0x6b0 fs/namei.c:5366 stack backtrace: CPU: 1 UID: 0 PID: 12527 Comm: syz.7.499 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2043 check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x1520/0x2ce0 kernel/locking/lockdep.c:5237 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/rtmutex_api.c:559 [inline] mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:578 configfs_rmdir+0x5f0/0x950 fs/configfs/dir.c:1556 vfs_rmdir+0x3e9/0x6b0 fs/namei.c:5381 filename_rmdir+0x292/0x520 fs/namei.c:5438 __do_sys_rmdir fs/namei.c:5461 [inline] __se_sys_rmdir+0x2e/0x140 fs/namei.c:5458 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f74b0eede99 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f74af125028 EFLAGS: 00000246 ORIG_RAX: 0000000000000054 RAX: ffffffffffffffda RBX: 00007f74b1176090 RCX: 00007f74b0eede99 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000800 RBP: 00007f74b0f83eaf R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f74b1176128 R14: 00007f74b1176090 R15: 00007ffdc0ba11b8 --- 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