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AHgh+Rr/AhNgK3ro24YwsVYk5TYgYsgO0iNRv8uXaQFPTT1FsydTkF7NJmuDpvMEOwgSyvAN2iKIrePvEgc=@vger.kernel.org X-Gm-Message-State: AOJu0YzzdiP+VMSB1StZwDgUMVjRtcAkVAEDeCcK2bswQrDqgD7S/rhe fOT1ssMvQjTYNS/C13M2vmB+39MYPlBsL1CrMohekgkyEAWv6Qm+AMfGWiiCueMJPis1MCbs/X4 9K5OGjHoDIR6YwP6EMPuvbef8EcYnNvEkLp8G51susdAScc9E8n2jNZlz7yg= Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6808:1527:b0:48f:a9f3:1c38 with SMTP id 5614622812f47-4ad5b7fde6bmr1431437b6e.2.1785246081831; Tue, 28 Jul 2026 06:41:21 -0700 (PDT) Date: Tue, 28 Jul 2026 06:41:21 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a68b181.4c659fcc.19cd90.001f.GAE@google.com> Subject: [syzbot] [usb?] possible deadlock in uvcg_streaming_header_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=16bfd746580000 kernel config: https://syzkaller.appspot.com/x/.config?x=cb17729fb04b1e3a dashboard link: https://syzkaller.appspot.com/bug?extid=ed4b9a6a61280b24d9c3 compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=101fe09e580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=100886b9580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/d0d4e9604889/disk-48a5a7ab.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/d0017d0f35e6/vmlinux-48a5a7ab.xz kernel image: https://storage.googleapis.com/syzbot-assets/81888db0a443/bzImage-48a5a7ab.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+ed4b9a6a61280b24d9c3@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.0.18/5837 is trying to acquire lock: ffffffff8ef6f000 (gadget_subsys.su_mutex){+.+.}-{4:4}, at: uvcg_streaming_header_allow_link+0x75/0x4d0 drivers/usb/gadget/function/uvc_configfs.c:1750 but task is already holding lock: ffff88803cdb6830 (&sb->s_type->i_mutex_key#24){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline] ffff88803cdb6830 (&sb->s_type->i_mutex_key#24){+.+.}-{4:4}, at: configfs_symlink+0x3af/0x1030 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#24){+.+.}-{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_mkdir fs/namei.c:5336 [inline] __se_sys_mkdir+0x34/0x150 fs/namei.c:5333 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:2540 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_mkdir fs/namei.c:5336 [inline] __se_sys_mkdir+0x34/0x150 fs/namei.c:5333 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 uvcg_streaming_header_allow_link+0x75/0x4d0 drivers/usb/gadget/function/uvc_configfs.c:1750 configfs_symlink+0x59a/0x1030 fs/configfs/symlink.c:196 vfs_symlink+0x18b/0x330 fs/namei.c:5660 filename_symlinkat+0x1cd/0x420 fs/namei.c:5685 __do_sys_symlink fs/namei.c:5712 [inline] __se_sys_symlink+0x4d/0x2b0 fs/namei.c:5708 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#24 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sb->s_type->i_mutex_key#24); lock(&opts->dep_lock); lock(&sb->s_type->i_mutex_key#24); lock(gadget_subsys.su_mutex); *** DEADLOCK *** 2 locks held by syz.0.18/5837: #0: ffff88801bf26500 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:494 #1: ffff88803cdb6830 (&sb->s_type->i_mutex_key#24){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline] #1: ffff88803cdb6830 (&sb->s_type->i_mutex_key#24){+.+.}-{4:4}, at: configfs_symlink+0x3af/0x1030 fs/configfs/symlink.c:186 stack backtrace: CPU: 1 UID: 0 PID: 5837 Comm: syz.0.18 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 uvcg_streaming_header_allow_link+0x75/0x4d0 drivers/usb/gadget/function/uvc_configfs.c:1750 configfs_symlink+0x59a/0x1030 fs/configfs/symlink.c:196 vfs_symlink+0x18b/0x330 fs/namei.c:5660 filename_symlinkat+0x1cd/0x420 fs/namei.c:5685 __do_sys_symlink fs/namei.c:5712 [inline] __se_sys_symlink+0x4d/0x2b0 fs/namei.c:5708 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: 0033:0x7f02ea0fde99 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:00007ffed3700ec8 EFLAGS: 00000246 ORIG_RAX: 0000000000000058 RAX: ffffffffffffffda RBX: 00007f02ea385fa0 RCX: 00007f02ea0fde99 RDX: 0000000000000000 RSI: 0000200000001500 RDI: 0000200000001400 RBP: 00007f02ea193eaf R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f02ea385fac R14: 00007f02ea385fa0 R15: 00007f02ea385fa0 --- 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 syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing. 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