From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f77.google.com (mail-oo1-f77.google.com [209.85.161.77]) (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 8A98143CEF8 for ; Tue, 18 Aug 2026 08:56:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.77 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787043397; cv=none; b=Slwf+MTGmPxql1a2dY9AtniNEd6qmtkB4aU0uDVcdnrVWLVKW/bjq0PspgsuP8vnev79azfoQL87fQ8iYxpd9DISBolwuZq3NGW8Zd0QGE4EO8fMuXsQh462IjpGKP4ZiXS+JPP++T0T5Pqhln0kqSKB+pLSDb1b4KIA1RbrDFA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787043397; c=relaxed/simple; bh=nZu6WiKb8KuJJVZs144PW9PKFVh0eeTDgD3oJunSUoM=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=jwsLjyqq16O2lx98NfeiljpXww0SFtQnW8DDBWImqDEJSFsvS6fi40vJFO0f073sV30Gtq5u7OCCblJZeRUqaAykr2iilpeVudIT07YZOUmUo9HgfhymNg/7kRfukoQTa+qtCtqT+R4Vo96pPuZBolX8CGRC3bI8hw0Uid4MAms= 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=209.85.161.77 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-oo1-f77.google.com with SMTP id 006d021491bc7-6acbcb92d31so3885772eaf.1 for ; Tue, 18 Aug 2026 01:56:34 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787043393; x=1787648193; 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=ENI8MWt7Uf6kAha9jb7krNyo2Su1eqZJBp6mhmYxwEQ=; b=Aw1HKqc48oKd+zoJrM5THZscRNwTdvFohu/1Raw9SbEeYuiOMc6CI4TG4UEOh+MqlP of5IQQWoysHCefBlqYAvL85G1uxbzhYIjEFNs4fqqXZM3F9E59nbUfrX54SisTsc5KD+ D8d8cKU91iFDvYbO0QvdNZSRCcSie+9UcI99IN7U3uJIux/B9NH2C9Dj6O1F5ZYAWqQP +FuSODdLUIm/p+deZYmffMkk3hMZjkmUHxt5NupjNb+DgwBmM+7w08hIpaFKG13PsWg9 EyZR0H1Vvl/M/Kc+fn+Ci7iHMQSSEnfvfwUgFJ6ar7yxx1FOwaSAJJr0cDEkUQ0SpaL7 w2CA== X-Forwarded-Encrypted: i=1; AHgh+RqKCuGXOtTGBIRdkmrH8rDSgCq0n3FtZTgfaglyb4roIX8L8OBb618o2h+t6vWLhRwqzn3rasWrMy11b7E=@vger.kernel.org X-Gm-Message-State: AOJu0YzSbc7W4A2k/0RttVfhjnzHyYCCg6QHlaSyO1vrynj1Snq6/vbG OBYG6ELPFdLWy77syqpgPnTonjsORfmJaGFfWaevaRFCIvbzD10S4r3kc5W+6ypxRZwZuGvRuP2 19fKs/P53t4X/RzB/0r8bYydCTtvs36qXsBVal4fWAoS1LQ/hQPkX4R/or1A= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:4c11:b0:6ac:a539:bc41 with SMTP id 006d021491bc7-6b0d613c77emr25139158eaf.12.1787043392998; Tue, 18 Aug 2026 01:56:32 -0700 (PDT) Date: Tue, 18 Aug 2026 01:56:32 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a841e40.c8649fcc.3bb87.0003.GAE@google.com> Subject: [syzbot] [fs?] possible deadlock in uvcg_mjpeg_bma_controls_show 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: 8d3ae59288f1 Linux 7.2 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=10b1d69e580000 kernel config: https://syzkaller.appspot.com/x/.config?x=2ca5f2f2c4197664 dashboard link: https://syzkaller.appspot.com/bug?extid=2b082cefcfb1439289ef 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/79f5b21ede1d/disk-8d3ae592.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/0f43313295ab/vmlinux-8d3ae592.xz kernel image: https://storage.googleapis.com/syzbot-assets/5de229a3986e/bzImage-8d3ae592.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+2b082cefcfb1439289ef@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.9.535/9115 is trying to acquire lock: ffffffff8f9eb768 (gadget_subsys.su_mutex){+.+.}-{4:4}, at: uvcg_format_bma_controls_show drivers/usb/gadget/function/uvc_configfs.c:1681 [inline] ffffffff8f9eb768 (gadget_subsys.su_mutex){+.+.}-{4:4}, at: uvcg_mjpeg_bma_controls_show+0x4d/0x140 drivers/usb/gadget/function/uvc_configfs.c:2635 but task is already holding lock: ffff88803207b570 (&p->frag_sem){++++}-{4:4}, at: fill_read_buffer fs/configfs/file.c:66 [inline] ffff88803207b570 (&p->frag_sem){++++}-{4:4}, at: configfs_read_iter+0x1cc/0x620 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}: 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#27){++++}-{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_format_bma_controls_show drivers/usb/gadget/function/uvc_configfs.c:1681 [inline] uvcg_mjpeg_bma_controls_show+0x4d/0x140 drivers/usb/gadget/function/uvc_configfs.c:2635 fill_read_buffer fs/configfs/file.c:68 [inline] configfs_read_iter+0x2b7/0x620 fs/configfs/file.c:88 __kernel_read+0x4ca/0x960 fs/read_write.c:532 integrity_kernel_read+0x89/0xd0 security/integrity/iint.c:28 ima_calc_file_hash_tfm security/integrity/ima/ima_crypto.c:222 [inline] ima_calc_file_hash+0x451/0x890 security/integrity/ima/ima_crypto.c:280 ima_collect_measurement+0x51b/0xa00 security/integrity/ima/ima_api.c:300 process_measurement+0x1272/0x1c10 security/integrity/ima/ima_main.c:425 ima_file_check+0xe1/0x130 security/integrity/ima/ima_main.c:685 security_file_post_open+0xb3/0x260 security/security.c:2755 do_open fs/namei.c:4702 [inline] path_openat+0x2e90/0x3830 fs/namei.c:4863 do_file_open+0x23e/0x4a0 fs/namei.c:4892 do_sys_openat2+0x115/0x200 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+0x138/0x170 fs/open.c:1385 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#27 --> &p->frag_sem Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(&p->frag_sem); lock(&sb->s_type->i_mutex_key#27); lock(&p->frag_sem); lock(gadget_subsys.su_mutex); *** DEADLOCK *** 3 locks held by syz.9.535/9115: #0: ffff88807ddab480 (&ima_iint_mutex_key[depth]){+.+.}-{4:4}, at: process_measurement+0x7d0/0x1c10 security/integrity/ima/ima_main.c:319 #1: ffff88801f7dd080 (&buffer->mutex){+.+.}-{4:4}, at: configfs_read_iter+0x70/0x620 fs/configfs/file.c:86 #2: ffff88803207b570 (&p->frag_sem){++++}-{4:4}, at: fill_read_buffer fs/configfs/file.c:66 [inline] #2: ffff88803207b570 (&p->frag_sem){++++}-{4:4}, at: configfs_read_iter+0x1cc/0x620 fs/configfs/file.c:88 stack backtrace: CPU: 0 UID: 0 PID: 9115 Comm: syz.9.535 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_format_bma_controls_show drivers/usb/gadget/function/uvc_configfs.c:1681 [inline] uvcg_mjpeg_bma_controls_show+0x4d/0x140 drivers/usb/gadget/function/uvc_configfs.c:2635 fill_read_buffer fs/configfs/file.c:68 [inline] configfs_read_iter+0x2b7/0x620 fs/configfs/file.c:88 __kernel_read+0x4ca/0x960 fs/read_write.c:532 integrity_kernel_read+0x89/0xd0 security/integrity/iint.c:28 ima_calc_file_hash_tfm security/integrity/ima/ima_crypto.c:222 [inline] ima_calc_file_hash+0x451/0x890 security/integrity/ima/ima_crypto.c:280 ima_collect_measurement+0x51b/0xa00 security/integrity/ima/ima_api.c:300 process_measurement+0x1272/0x1c10 security/integrity/ima/ima_main.c:425 ima_file_check+0xe1/0x130 security/integrity/ima/ima_main.c:685 security_file_post_open+0xb3/0x260 security/security.c:2755 do_open fs/namei.c:4702 [inline] path_openat+0x2e90/0x3830 fs/namei.c:4863 do_file_open+0x23e/0x4a0 fs/namei.c:4892 do_sys_openat2+0x115/0x200 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+0x138/0x170 fs/open.c:1385 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: 0033:0x7fc9faf9e0d9 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:00007fc9fbdd8028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fc9fb226180 RCX: 00007fc9faf9e0d9 RDX: 0000000000000002 RSI: 00002000000002c0 RDI: ffffffffffffff9c RBP: 00007fc9fb035024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc9fb226218 R14: 00007fc9fb226180 R15: 00007ffe7532db78 --- 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