From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ot1-f79.google.com (mail-ot1-f79.google.com [209.85.210.79]) (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 D5DE3E571 for ; Tue, 18 Aug 2026 00:29:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.79 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787012972; cv=none; b=J5IQregTznW0qvqzx9UnVKMoNCvK2y1vvMG6JQeBMt5zsTD+yrR94ZNxwTDpHEffAR0BdwX70As7CVFgv4gArHUEa+348FvioXLJtACxqXNTTC2xUvMV7kCOJFUCvJ7ZdUQv2dif2h/sOr74e2X2o99CVspwksd8/G6BiKFIMnk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787012972; c=relaxed/simple; bh=UuCchqbDEwctFuq8b0pty1cAkYgCBgZFTswO/9kdAAs=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=O9iPqC2LNk9ES7ika4KgkFZGG2v/50/RugU9VsRQWkgS7aZI9+6ofQRuCDZUZCLVov8Ogt1PuvRWyjJjDpq18WW3cQadmbeMPh+0lJdrPu/MswFYTQoUOhPqsBPMewZrLYyCEmZIr1SXK8wpVJ8MpVdIO4Mx/C31DHDd74q8Qsw= 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=209.85.210.79 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-ot1-f79.google.com with SMTP id 46e09a7af769-7e9f565a6e7so5516540a34.2 for ; Mon, 17 Aug 2026 17:29:30 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787012970; x=1787617770; 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=dbFmDevF/ewQr//rxE5Al15zDi6A8CIgeBT7RBb5/KA=; b=pXEE9dSP+6RLHNGzqAvt8PAQ2Zb43VYnOj8ZZ21lCxuYLoFPR7U5DdLSzxiriAIbBl YT3sXnBLdM2dMc8tCHiS/7G2fHacEqZzAp3g3TAHR1ICyTqrElG9ECN01oovxkJvKC3F rYHj/Az+gFbZzEDso3C/+/FzVsmM+l2woKh/FXmeVs77v63r9iAVz8aBXCU8LfdzWSi3 BEfqcarOMDQQwPkJEczj0VS39+c5qafZoySWxqFTYfl4PjpBiIL6mAtQuesoyGNevndn gPtcx7SpsiwE65ekP8Z4DRzvtxwGgrZLP9MP1gHjCAoK9ljbQC6pj5iimkHozut+p2/m PW4A== X-Forwarded-Encrypted: i=1; AHgh+RpMKAx7i4D4a7TPmwRHF8dwTmvLM6Md7q5EaQ0CB8FU/fw0O5WtG3aPr7vR6MbaZTSFsp0wZQB/4rPz76c=@vger.kernel.org X-Gm-Message-State: AOJu0YwvNloFhyeIzJU7ICwwP7PfenV0Q3XtgWtxjvh2ucX2oxQs/Jbu lXgmU2i3SuCnkv9ZXtYBHzE+Sxrum9WKQ6XpqIXq/+oG88f1NF2ZzAlU7+VkWEJIF086E5Zx4So 4wAj/LlHkMvKa5XjdTgnja1UZUZ24vPiBT70tJMLSJ+YI3u7xYQfGxiLSPfM= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:1627:b0:6af:eac8:3d92 with SMTP id 006d021491bc7-6b0d5daa746mr24203975eaf.0.1787012969814; Mon, 17 Aug 2026 17:29:29 -0700 (PDT) Date: Mon, 17 Aug 2026 17:29:29 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a83a769.4d75e56a.c9a88.0007.GAE@google.com> Subject: [syzbot] [fs?] possible deadlock in uvcg_extension_bm_controls_store 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: 3aa1dcaa4f6f Revert "wifi: mt76: Disable napi when removin.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1619d149580000 kernel config: https://syzkaller.appspot.com/x/.config?x=aaf0da806f995318 dashboard link: https://syzkaller.appspot.com/bug?extid=300213c2b5b55c0244f4 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/6f9bf8386a97/disk-3aa1dcaa.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/11e9065ece34/vmlinux-3aa1dcaa.xz kernel image: https://storage.googleapis.com/syzbot-assets/0c2427f0862d/bzImage-3aa1dcaa.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+300213c2b5b55c0244f4@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.1.302/7497 is trying to acquire lock: ffffffff8f9eb2a8 (gadget_subsys.su_mutex){+.+.}-{4:4}, at: uvcg_extension_bm_controls_store+0xe4/0xb00 drivers/usb/gadget/function/uvc_configfs.c:1125 but task is already holding lock: ffff88803317f470 (&p->frag_sem){++++}-{4:4}, at: flush_write_buffer fs/configfs/file.c:205 [inline] ffff88803317f470 (&p->frag_sem){++++}-{4:4}, at: configfs_write_iter+0x238/0x430 fs/configfs/file.c:229 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&p->frag_sem){++++}-{4:4}: down_write_killable+0xa6/0x240 kernel/locking/rwsem.c:1643 configfs_rmdir+0x3b0/0x950 fs/configfs/dir.c:1534 vfs_rmdir+0x3e6/0x6a0 fs/namei.c:5381 filename_rmdir+0x292/0x520 fs/namei.c:5438 __do_sys_unlinkat fs/namei.c:5613 [inline] __se_sys_unlinkat+0x71/0x1a0 fs/namei.c:5606 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 -> #2 (&sb->s_type->i_mutex_key#32){++++}-{4:4}: down_write+0x96/0x200 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+0x406/0x620 fs/namei.c:5276 filename_mkdirat+0x285/0x510 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/mutex.c:646 [inline] __mutex_lock+0x19d/0x1550 kernel/locking/mutex.c:821 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+0x406/0x620 fs/namei.c:5276 filename_mkdirat+0x285/0x510 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+0x1520/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x19d/0x1550 kernel/locking/mutex.c:821 uvcg_extension_bm_controls_store+0xe4/0xb00 drivers/usb/gadget/function/uvc_configfs.c:1125 flush_write_buffer fs/configfs/file.c:207 [inline] configfs_write_iter+0x337/0x430 fs/configfs/file.c:229 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x612/0xba0 fs/read_write.c:687 ksys_write+0x150/0x270 fs/read_write.c:739 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 --> &sb->s_type->i_mutex_key#32 --> &p->frag_sem Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(&p->frag_sem); lock(&sb->s_type->i_mutex_key#32); lock(&p->frag_sem); lock(gadget_subsys.su_mutex); *** DEADLOCK *** 4 locks held by syz.1.302/7497: #0: ffff888061692470 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259 #1: ffff88801bf16450 (sb_writers#22){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2733 [inline] #1: ffff88801bf16450 (sb_writers#22){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683 #2: ffff8880783f4480 (&buffer->mutex){+.+.}-{4:4}, at: configfs_write_iter+0x7e/0x430 fs/configfs/file.c:226 #3: ffff88803317f470 (&p->frag_sem){++++}-{4:4}, at: flush_write_buffer fs/configfs/file.c:205 [inline] #3: ffff88803317f470 (&p->frag_sem){++++}-{4:4}, at: configfs_write_iter+0x238/0x430 fs/configfs/file.c:229 stack backtrace: CPU: 0 UID: 0 PID: 7497 Comm: syz.1.302 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_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+0x1520/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x19d/0x1550 kernel/locking/mutex.c:821 uvcg_extension_bm_controls_store+0xe4/0xb00 drivers/usb/gadget/function/uvc_configfs.c:1125 flush_write_buffer fs/configfs/file.c:207 [inline] configfs_write_iter+0x337/0x430 fs/configfs/file.c:229 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x612/0xba0 fs/read_write.c:687 ksys_write+0x150/0x270 fs/read_write.c:739 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: 0033:0x7f9d8819e0d9 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:00007f9d890b3028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f9d88425fa0 RCX: 00007f9d8819e0d9 RDX: 0000000000000050 RSI: 0000200000000440 RDI: 0000000000000009 RBP: 00007f9d88235024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f9d88426038 R14: 00007f9d88425fa0 R15: 00007fffe7d8ced8 --- 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