From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oi1-f207.google.com (mail-oi1-f207.google.com [209.85.167.207]) (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 8B9563C871B for ; Wed, 19 Aug 2026 04:59:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.207 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787115583; cv=none; b=FtRWOwAzmySykEoy+2t3RZyT3hxiuelYjXX+jyi3GXagT4JPFTAolXpwJh1Tcp8i5ADaBPCqZJOPjlbD9XDk7QfuM+uazG0U9EbiZVXk6iIy1WnQvKOT/gEgwEqTgs8if5mMMgfnDo7d5sp+oslEyOebl3ZEDrQhqwWK8NIMSc0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787115583; c=relaxed/simple; bh=bo4znDchKDTpqKGuxejfa4Kzgk9A8y4VUNzbraNkAFQ=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=ilckJYi+nvF3mE7MGZekH7KBf7pWCRptwxed/RDNJIl/h2AyDOTLNWVpxPci97qekbsQy3X9m3jaCy37hyvkQMDTozvvSBZh3Zs1N8D0xzquhbqm9Q1COEpc48UQblr9sz8sulEYej7mhBV2jHYnUnkbSbdApDFv/Z1PC46xkmE= 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=209.85.167.207 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-oi1-f207.google.com with SMTP id 5614622812f47-4b28d8d1b76so538375b6e.3 for ; Tue, 18 Aug 2026 21:59:41 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787115580; x=1787720380; 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=Hu5Ps8lSVhPkxS4r+5ohowZQxB42afhKLWR6caqDX0g=; b=eP5mGobJSePqVtdxRaRMcdXItoFGsE3JmjextirUbNuIhPI+gHgvqawk06g08my4zu DkAmJcppKBhNbzyEmDQ97HC/tuGvnJexbhRr7YQmhehUcz8Spch4IrxEHYjeOEI3n4cK Z4vI8Ix0v0r78fOD+UsaQsXhHTB0rCjqIKyhk81TpBG+l00OnV7IgxXJzy/6UOdnBJkB RQu963uCOhG+Y61pIIqKmNcamOz75ncmNyPBfvwXsZIH3rZqaBulBIAV+AKYd4Mg92+b qJlVSjcZSzl+Uo+6b3EZwr+5g7fWeNrPdONyI3z86mBgBsr0w7XzVH0tofU5cIZ59CFg Becg== X-Forwarded-Encrypted: i=1; AHgh+Rp3PeBXNK/kd6nuX1U/65jbAhBPQhJAu5wy5jrYO3/HV7cwtcovuC1qALb6R4/TqG7VvGVFDsY82yEliJ8=@vger.kernel.org X-Gm-Message-State: AOJu0YwY8Rw8kzBkYkKpF7jRcKbagU0xaBrInM21MAEa5GtRidOr/UQ9 6e3FIiFFfdhhDpfUZhdJ8lCxrreiNYkiwUVhwECZUPpnD9I+N4sGJqOskuERMbjq9ztPFzTjqPB UtQeon5sKXw5TMpLtUlx0hnbkNNkhxgPbVpcWVxv2NFQV7eJBPWXEozPisoQ= 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:bc4:b0:496:a36:b5e5 with SMTP id 5614622812f47-4b2bcac63e5mr2082822b6e.17.1787115580451; Tue, 18 Aug 2026 21:59:40 -0700 (PDT) Date: Tue, 18 Aug 2026 21:59:40 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a85383c.c8649fcc.3bb87.000c.GAE@google.com> Subject: [syzbot] [fs?] possible deadlock in uvcg_frame_w_width_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: 8d3ae59288f1 Linux 7.2 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=143c0679580000 kernel config: https://syzkaller.appspot.com/x/.config?x=1d67342c314f228d dashboard link: https://syzkaller.appspot.com/bug?extid=35082e842882ade33a27 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/d7827cbad2ef/disk-8d3ae592.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/eb86c4d0d627/vmlinux-8d3ae592.xz kernel image: https://storage.googleapis.com/syzbot-assets/108cb159a1ee/bzImage-8d3ae592.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+35082e842882ade33a27@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.9.5185/30580 is trying to acquire lock: ffffffff903ca368 (gadget_subsys.su_mutex){+.+.}-{4:4}, at: uvcg_frame_w_width_store+0x12c/0x370 drivers/usb/gadget/function/uvc_configfs.c:2029 but task is already holding lock: ffff888074199270 (&p->frag_sem){++++}-{4:4}, at: flush_write_buffer fs/configfs/file.c:205 [inline] ffff888074199270 (&p->frag_sem){++++}-{4:4}, at: configfs_write_iter+0x218/0x4e0 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}: 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_frame_w_width_store+0x12c/0x370 drivers/usb/gadget/function/uvc_configfs.c:2029 flush_write_buffer fs/configfs/file.c:207 [inline] configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6ac/0x1050 fs/read_write.c:687 ksys_write+0x12a/0x250 fs/read_write.c:739 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 *** 4 locks held by syz.9.5185/30580: #0: ffff88802728b5f0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259 #1: ffff88801e70c450 (sb_writers#16){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739 #2: ffff88807b926080 (&buffer->mutex){+.+.}-{4:4}, at: configfs_write_iter+0x76/0x4e0 fs/configfs/file.c:226 #3: ffff888074199270 (&p->frag_sem){++++}-{4:4}, at: flush_write_buffer fs/configfs/file.c:205 [inline] #3: ffff888074199270 (&p->frag_sem){++++}-{4:4}, at: configfs_write_iter+0x218/0x4e0 fs/configfs/file.c:229 stack backtrace: CPU: 0 UID: 0 PID: 30580 Comm: syz.9.5185 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_frame_w_width_store+0x12c/0x370 drivers/usb/gadget/function/uvc_configfs.c:2029 flush_write_buffer fs/configfs/file.c:207 [inline] configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6ac/0x1050 fs/read_write.c:687 ksys_write+0x12a/0x250 fs/read_write.c:739 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: 0033:0x7fad2b59e0d9 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:00007fad297d5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fad2b826090 RCX: 00007fad2b59e0d9 RDX: 0000000000000001 RSI: 0000200000000540 RDI: 0000000000000004 RBP: 00007fad2b635024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fad2b826128 R14: 00007fad2b826090 R15: 00007ffeda500b18 --- 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