From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oa1-f80.google.com (mail-oa1-f80.google.com [209.85.160.80]) (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 5167D126C02 for ; Wed, 29 Jul 2026 00:09:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.80 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785283767; cv=none; b=flZvkbWTnbLI3bTMEszb/Zdcgid96JJ+BQuMPY5dbmJn53negrNoz5e4TSZJERaWaZMdyOA5BpBWPEbzk8EZdYX83LvIIpi/b77REWzFPeSE6UIEthKt2tKjBmo8T+DJeOKCP3wq+NTv7k6ynxnHARYX+BJLUxbwu3YK8ij1jYk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785283767; c=relaxed/simple; bh=mymrFFmfdaNisZ/BQLYHeO2mC0e+bT+w9hjr96S2GtI=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=djtLYYPgWOoTznaBVV7L48wDXJF/itpMAIIKdA41QE3rHusui/RzEqAcvb6ADiJVRfZ5QtV7Qzn7ugezOLSXNMIpEyVCfwWBx7HhA1eiHrwxFRqFW9pb6cGvlWxBA21TpPR5Vgx2wyLqtHYqkgjhlfkqorJSTwSfVL99c5hDkLE= 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=209.85.160.80 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-oa1-f80.google.com with SMTP id 586e51a60fabf-451ff8b9acbso1318270fac.0 for ; Tue, 28 Jul 2026 17:09:26 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1785283765; x=1785888565; 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=BwGX7c7rJExJbY+17jI7JSnqUL/QGXoKbkbyLRIDlfM=; b=Ul3CXZDEeBOfeoDrz2LGcW1E8FGqK1PthMoPHbdBRm95EE4HRom63L0H8V2wWZnJAp AcQK/sdkrK4umZ3fJrDoz3CDrvJJ9tEiRdr1wpcM4h2hAVI5sx+CIQVR7Oi/ukCgbHiq yMtyTdteRVmOqrzr/UIXxrQKzCABjpIVyzJaS2WXziuKxiirww+ki9jQbKVn29N/VBFG 63iyWBcDCSN/6c+er59PqfDybfGfyRXXJM+feqD0VdypadmoN3bnslmuzno612/+ODLi +ugB9kuSmrsjO6Vu6HtnPjiXu0FDEnHQE9g8pv3euVqJvwwwE2GYYJRHR41CRYGk1vyJ bwyA== X-Forwarded-Encrypted: i=1; AHgh+Rq5qctCQFnRuG155LJfFOFVP7H5NAheZ24SMaTZ4YjJo9GKYm+21Gjjv9ytQBR9fzLaP6vXh3JWNqLB06I=@vger.kernel.org X-Gm-Message-State: AOJu0YxcZ1251lcU0rdvViNXTevkyEaF7fpAPADmeXd8imFBX7QCe1a6 qtzhfto8Uefkn6wz/FkPYmk6+qGk9eM4Edpo45/AlKlHQH4JzplC2h4tzt5VZbDGYQ3CJgn2QAq 2MqD3Z17rplptTAfHSlYvKwi3Jvt4dpFl+hx1cW53s/Qso06wDcfMHjYuPbM= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6808:f13:b0:495:fd92:841f with SMTP id 5614622812f47-4ad733b8878mr55318b6e.23.1785283764929; Tue, 28 Jul 2026 17:09:24 -0700 (PDT) Date: Tue, 28 Jul 2026 17:09:24 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a6944b4.d9e86bb5.297b12.003c.GAE@google.com> Subject: [syzbot] [usb?] possible deadlock in uvc_func_allow_link From: syzbot To: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 48a5a7ab8d6a Merge tag 'v7.2-rc4-smb3-client-fixes' of git.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1198109e580000 kernel config: https://syzkaller.appspot.com/x/.config?x=145fa60d73086782 dashboard link: https://syzkaller.appspot.com/bug?extid=8c0a48f6c8357c9da819 compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/1eb5b7aa9ec5/disk-48a5a7ab.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/965506e050aa/vmlinux-48a5a7ab.xz kernel image: https://storage.googleapis.com/syzbot-assets/662778208054/bzImage-48a5a7ab.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+8c0a48f6c8357c9da819@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.9.4116/22505 is trying to acquire lock: ffffffff901cfe68 (gadget_subsys.su_mutex){+.+.}-{4:4}, at: uvc_func_allow_link+0x76/0x3f0 drivers/usb/gadget/function/uvc_configfs.c:3651 but task is already holding lock: ffff888057290f80 (&sb->s_type->i_mutex_key#28){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline] ffff888057290f80 (&sb->s_type->i_mutex_key#28){++++}-{4:4}, at: configfs_symlink+0x3c0/0x11f0 fs/configfs/symlink.c:186 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&sb->s_type->i_mutex_key#28){++++}-{4:4}: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825 down_write+0x8b/0x1f0 kernel/locking/rwsem.c:1631 inode_lock include/linux/fs.h:1024 [inline] configfs_depend_item_unlocked+0xf3/0x6a0 fs/configfs/dir.c:1259 usbg_make_tpg+0x261/0x620 drivers/usb/gadget/function/f_tcm.c:1686 target_fabric_make_tpg+0xab/0x8c0 drivers/target/target_core_fabric_configfs.c:939 configfs_mkdir+0x51e/0xb70 fs/configfs/dir.c:1360 vfs_mkdir+0x361/0x850 fs/namei.c:5276 filename_mkdirat+0x48b/0x5e0 fs/namei.c:5309 __do_sys_mkdirat fs/namei.c:5330 [inline] __se_sys_mkdirat fs/namei.c:5327 [inline] __x64_sys_mkdirat+0x89/0xc0 fs/namei.c:5327 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&opts->dep_lock){+.+.}-{4:4}: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821 tcm_set_name+0x29/0xb0 drivers/usb/gadget/function/f_tcm.c:2540 function_make+0x21c/0x3f0 drivers/usb/gadget/configfs.c:636 configfs_mkdir+0x51e/0xb70 fs/configfs/dir.c:1360 vfs_mkdir+0x361/0x850 fs/namei.c:5276 filename_mkdirat+0x48b/0x5e0 fs/namei.c:5309 __do_sys_mkdirat fs/namei.c:5330 [inline] __se_sys_mkdirat fs/namei.c:5327 [inline] __x64_sys_mkdirat+0x89/0xc0 fs/namei.c:5327 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (gadget_subsys.su_mutex){+.+.}-{4:4}: check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3165 check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x136c/0x1a40 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821 uvc_func_allow_link+0x76/0x3f0 drivers/usb/gadget/function/uvc_configfs.c:3651 configfs_symlink+0x540/0x11f0 fs/configfs/symlink.c:196 vfs_symlink fs/namei.c:5660 [inline] vfs_symlink+0x178/0x4d0 fs/namei.c:5639 filename_symlinkat+0x2a6/0x560 fs/namei.c:5685 __do_sys_symlink fs/namei.c:5712 [inline] __se_sys_symlink fs/namei.c:5708 [inline] __x64_sys_symlink+0x79/0xb0 fs/namei.c:5708 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 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#28 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sb->s_type->i_mutex_key#28); lock(&opts->dep_lock); lock(&sb->s_type->i_mutex_key#28); lock(gadget_subsys.su_mutex); *** DEADLOCK *** 2 locks held by syz.9.4116/22505: #0: ffff88801e3b0450 (sb_writers#17){.+.+}-{0:0}, at: filename_create+0x10d/0x400 fs/namei.c:4948 #1: ffff888057290f80 (&sb->s_type->i_mutex_key#28){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline] #1: ffff888057290f80 (&sb->s_type->i_mutex_key#28){++++}-{4:4}, at: configfs_symlink+0x3c0/0x11f0 fs/configfs/symlink.c:186 stack backtrace: CPU: 0 UID: 0 PID: 22505 Comm: syz.9.4116 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_circular_bug.cold+0x178/0x1c7 kernel/locking/lockdep.c:2043 check_noncircular+0x146/0x160 kernel/locking/lockdep.c:2175 check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3165 check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x136c/0x1a40 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821 uvc_func_allow_link+0x76/0x3f0 drivers/usb/gadget/function/uvc_configfs.c:3651 configfs_symlink+0x540/0x11f0 fs/configfs/symlink.c:196 vfs_symlink fs/namei.c:5660 [inline] vfs_symlink+0x178/0x4d0 fs/namei.c:5639 filename_symlinkat+0x2a6/0x560 fs/namei.c:5685 __do_sys_symlink fs/namei.c:5712 [inline] __se_sys_symlink fs/namei.c:5708 [inline] __x64_sys_symlink+0x79/0xb0 fs/namei.c:5708 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff24159de99 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:00007ff2423d2028 EFLAGS: 00000246 ORIG_RAX: 0000000000000058 RAX: ffffffffffffffda RBX: 00007ff241825fa0 RCX: 00007ff24159de99 RDX: 0000000000000000 RSI: 00002000000000c0 RDI: 0000200000000040 RBP: 00007ff241633eaf R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ff241826038 R14: 00007ff241825fa0 R15: 00007ffd6dfc08d8 --- 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