From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ot1-f78.google.com (mail-ot1-f78.google.com [209.85.210.78]) (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 9AAE11624D5 for ; Thu, 13 Aug 2026 00:08:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.78 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786579716; cv=none; b=d1L5FFEXfp10fwkpB6dP7gm9t578Jr9EB6yWDjSLbsr3GPNGJ1LOJNMfiCqlM/neJ+eBG39gs9gGOp97YpNKdOhXqv9SrRKq5pK1iJoqmjEKpHz2pT2DaVmeOdESH5U6UHgjFJ+NcnJfs6wSEo6AcEiurw45l5E7Ye/l1lJyReI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786579716; c=relaxed/simple; bh=9EbMNFwz+jBywKTs3Umqf6kQXWaNN0/SedVsIrlsQOM=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=WM//KW6DqMdP6ffj+qicn/P4yk570eQOIk31HgotRGe8ziE406F0GIBq/4uCcLhopXlodpdBYvOwuNIpKr0VaD5Q6Py385xlsCjOzWMMelUOnfEL7i46bFZdACunDBl3y19IU3og1me59cgQAOjOrWGCnTt51MTbBkiNS+4i7ZU= 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=209.85.210.78 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-f78.google.com with SMTP id 46e09a7af769-7e7624e584dso2085014a34.2 for ; Wed, 12 Aug 2026 17:08:34 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1786579713; x=1787184513; 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=ilWwyx6+AJPN6SCJ+8pSs3Yxjxu0RGf98MaguQhjz8k=; b=T0RlEGAQGFLCf/BDPPnRcsJzwhCC0ttEGRhyfwGIH1g3Xa0qeaG3qK/FNa1bCxE1yS Qd9VTv/y9cMEIBUx++MuPr5bTedfdPNqil+7g2C/0uuSucK/Tx1vtDP4pToSGZw1gxYN tgyukHwggZ7h8fd/dPwP9trU1sGxT5z45EtxfXZPb9YICCjp6Iwtkoy11iWO8aMPwiFq /HMhdn6JmXJYTfcxr2YGrBR1VB/j0d5WWlf+GXxjyU7+aa+fS9zVO97AoyRopIBEpkcb KMg0djSehrOjlcL9Tias6XaSBFqqK2aJ8oIIMbA4jp2BzEK1fjlaEg1Gl5r5UduoxSIm v0zw== X-Forwarded-Encrypted: i=1; AHgh+Rre3A6BGSaNds4PA0Zolx6VxAFfWelpsKXJA1L+NUlmhr0k+xi1fndcPF2FIyuInNycQMD4BknZQfOrLeE=@vger.kernel.org X-Gm-Message-State: AOJu0YzkILhiJQp4cstSosGRvun+UNyWpzA/DflMYcOYJTZvRk8DtzXf Zbg37PBvA/qrzW5234xg2rHThEvJt7GZqH0Il4L/bnBTl1CzGXtf45HooNRY7GM2mECmDuL6C+S q7QBSOLxPXBcylFH3i3H6j/itAM/Cg9X0L3iFMncgBZiBXzSBKmDWPLgGJXg= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:4b84:b0:6b0:1b82:89a3 with SMTP id 006d021491bc7-6b0c42166ccmr2190526eaf.9.1786579713529; Wed, 12 Aug 2026 17:08:33 -0700 (PDT) Date: Wed, 12 Aug 2026 17:08:33 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a7d0b01.3668565d.e8814.0018.GAE@google.com> Subject: [syzbot] [usb?] possible deadlock in uvcg_extension_ba_source_id_show 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: a59f57e2aa12 Merge tag 'watchdog-for-v7.2-rc7' of git://gi.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=17bd6132580000 kernel config: https://syzkaller.appspot.com/x/.config?x=c44651ea7dd2f307 dashboard link: https://syzkaller.appspot.com/bug?extid=caf0e2bd08dda787005d 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/6e78675a9575/disk-a59f57e2.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/8214e30981cd/vmlinux-a59f57e2.xz kernel image: https://storage.googleapis.com/syzbot-assets/44559008ddee/bzImage-a59f57e2.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+caf0e2bd08dda787005d@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.6.7608/806 is trying to acquire lock: ffffffff901c9de8 (gadget_subsys.su_mutex){+.+.}-{4:4}, at: uvcg_extension_ba_source_id_show+0x7c/0x310 drivers/usb/gadget/function/uvc_configfs.c:1018 but task is already holding lock: ffff888029758570 (&p->frag_sem){++++}-{4:4}, at: fill_read_buffer fs/configfs/file.c:66 [inline] ffff888029758570 (&p->frag_sem){++++}-{4:4}, at: configfs_read_iter+0x346/0x6f0 fs/configfs/file.c:88 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&p->frag_sem){++++}-{4:4}: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825 down_write_killable+0x93/0x250 kernel/locking/rwsem.c:1643 configfs_rmdir+0x3fa/0x950 fs/configfs/dir.c:1534 vfs_rmdir fs/namei.c:5381 [inline] vfs_rmdir+0x328/0x8a0 fs/namei.c:5354 filename_rmdir+0x31a/0x5c0 fs/namei.c:5438 __do_sys_unlinkat fs/namei.c:5613 [inline] __se_sys_unlinkat fs/namei.c:5606 [inline] __x64_sys_unlinkat+0xf5/0x130 fs/namei.c:5606 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 -> #2 (&sb->s_type->i_mutex_key#26){++++}-{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_mkdir fs/namei.c:5336 [inline] __se_sys_mkdir fs/namei.c:5333 [inline] __x64_sys_mkdir+0x6b/0x90 fs/namei.c:5333 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:2669 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_mkdir fs/namei.c:5336 [inline] __se_sys_mkdir fs/namei.c:5333 [inline] __x64_sys_mkdir+0x6b/0x90 fs/namei.c:5333 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 uvcg_extension_ba_source_id_show+0x7c/0x310 drivers/usb/gadget/function/uvc_configfs.c:1018 fill_read_buffer fs/configfs/file.c:68 [inline] configfs_read_iter+0x426/0x6f0 fs/configfs/file.c:88 __kernel_read+0x397/0xad0 fs/read_write.c:532 integrity_kernel_read+0x7e/0xb0 security/integrity/iint.c:28 ima_calc_file_hash_tfm+0x25e/0x350 security/integrity/ima/ima_crypto.c:222 ima_calc_file_hash+0x1e3/0x380 security/integrity/ima/ima_crypto.c:280 ima_collect_measurement+0x94f/0xb30 security/integrity/ima/ima_api.c:300 process_measurement+0xdfe/0x2350 security/integrity/ima/ima_main.c:425 ima_file_check+0xc3/0x110 security/integrity/ima/ima_main.c:685 security_file_post_open+0xc4/0x210 security/security.c:2755 do_open fs/namei.c:4702 [inline] path_openat+0x985/0x4280 fs/namei.c:4863 do_file_open+0x20e/0x430 fs/namei.c:4892 do_sys_openat2+0x10f/0x1e0 fs/open.c:1368 do_sys_open fs/open.c:1374 [inline] __do_sys_openat fs/open.c:1390 [inline] __se_sys_openat fs/open.c:1385 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1385 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 --> &sb->s_type->i_mutex_key#26 --> &p->frag_sem Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(&p->frag_sem); lock(&sb->s_type->i_mutex_key#26); lock(&p->frag_sem); lock(gadget_subsys.su_mutex); *** DEADLOCK *** 3 locks held by syz.6.7608/806: #0: ffff888076b259a8 (&ima_iint_mutex_key[depth]){+.+.}-{4:4}, at: process_measurement+0x5ab/0x2350 security/integrity/ima/ima_main.c:319 #1: ffff888053486480 (&buffer->mutex){+.+.}-{4:4}, at: configfs_read_iter+0x79/0x6f0 fs/configfs/file.c:86 #2: ffff888029758570 (&p->frag_sem){++++}-{4:4}, at: fill_read_buffer fs/configfs/file.c:66 [inline] #2: ffff888029758570 (&p->frag_sem){++++}-{4:4}, at: configfs_read_iter+0x346/0x6f0 fs/configfs/file.c:88 stack backtrace: CPU: 1 UID: 0 PID: 806 Comm: syz.6.7608 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 uvcg_extension_ba_source_id_show+0x7c/0x310 drivers/usb/gadget/function/uvc_configfs.c:1018 fill_read_buffer fs/configfs/file.c:68 [inline] configfs_read_iter+0x426/0x6f0 fs/configfs/file.c:88 __kernel_read+0x397/0xad0 fs/read_write.c:532 integrity_kernel_read+0x7e/0xb0 security/integrity/iint.c:28 ima_calc_file_hash_tfm+0x25e/0x350 security/integrity/ima/ima_crypto.c:222 ima_calc_file_hash+0x1e3/0x380 security/integrity/ima/ima_crypto.c:280 ima_collect_measurement+0x94f/0xb30 security/integrity/ima/ima_api.c:300 process_measurement+0xdfe/0x2350 security/integrity/ima/ima_main.c:425 ima_file_check+0xc3/0x110 security/integrity/ima/ima_main.c:685 security_file_post_open+0xc4/0x210 security/security.c:2755 do_open fs/namei.c:4702 [inline] path_openat+0x985/0x4280 fs/namei.c:4863 do_file_open+0x20e/0x430 fs/namei.c:4892 do_sys_openat2+0x10f/0x1e0 fs/open.c:1368 do_sys_open fs/open.c:1374 [inline] __do_sys_openat fs/open.c:1390 [inline] __se_sys_openat fs/open.c:1385 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1385 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: 0033:0x7f5bde79e0d9 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:00007f5bdf692028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f5bdea25fa0 RCX: 00007f5bde79e0d9 RDX: 0000000000000002 RSI: 0000200000000240 RDI: ffffffffffffff9c RBP: 00007f5bde835024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f5bdea26038 R14: 00007f5bdea25fa0 R15: 00007ffedc4f6578 --- 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