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AJvYcCXZd17IVnOSS2PIzvW0m7E08qyOw86eApsVa67vneIIO7zv4xhQgmB7XYY2mR7wOc2DP5iSyej9owYrnfL+@vger.kernel.org X-Gm-Message-State: AOJu0YyVNMn0xiv9k3oPDgS5ud5QtkU6y4/G4r1v4l04zhmkyLx0P4pC UdEAZiLj1TTIs2engI+O16U9N54+uWTQ0dn040xwhXbJ/tmYrjNpk0dtP25O4KP3kuwFgQlcToh StCr4utjQHtK/3aa3kz/6NZ1cJY7SX6rVYACIRtwNaJDXlNot6uNgplItJx4= X-Google-Smtp-Source: AGHT+IFByml6kwKuEIpQl6nNAhFNnDTZqBEAngdpOCN6AS9dK/ei40xzv92OXTKBzHdMCvzMOH0j9/F/X7Yt5TQXQY+qBCBrF3WX Precedence: bulk X-Mailing-List: linux-unionfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6e02:2146:b0:433:7a5f:9439 with SMTP id e9e14a558f8ab-435b98c6abbmr251866885ab.24.1764421523738; Sat, 29 Nov 2025 05:05:23 -0800 (PST) Date: Sat, 29 Nov 2025 05:05:23 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <692aef93.a70a0220.d98e3.015b.GAE@google.com> Subject: [syzbot] [overlayfs?] WARNING in fast_dput From: syzbot To: amir73il@gmail.com, brauner@kernel.org, jack@suse.cz, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-unionfs@vger.kernel.org, miklos@szeredi.hu, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 7d31f578f323 Add linux-next specific files for 20251128 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=14db5f42580000 kernel config: https://syzkaller.appspot.com/x/.config?x=6336d8e94a7c517d dashboard link: https://syzkaller.appspot.com/bug?extid=b74150fd2ef40e716ca2 compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1780a112580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10f6be92580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/6b49d8ad90de/disk-7d31f578.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/dbe2d4988ca7/vmlinux-7d31f578.xz kernel image: https://storage.googleapis.com/syzbot-assets/fc0448ab2411/bzImage-7d31f578.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+b74150fd2ef40e716ca2@syzkaller.appspotmail.com ------------[ cut here ]------------ WARNING: fs/dcache.c:829 at fast_dput+0x334/0x430 fs/dcache.c:829, CPU#1: syz.0.17/6053 Modules linked in: CPU: 1 UID: 0 PID: 6053 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:fast_dput+0x334/0x430 fs/dcache.c:829 Code: e3 81 ff 48 b8 00 00 00 00 00 fc ff df 41 0f b6 44 05 00 84 c0 0f 85 e2 00 00 00 41 80 0e 40 e9 fd fe ff ff e8 4d e3 81 ff 90 <0f> 0b 90 e9 ef fe ff ff 44 89 e6 81 e6 00 00 04 00 31 ff e8 74 e7 RSP: 0018:ffffc90003407cd8 EFLAGS: 00010293 RAX: ffffffff823fcfe3 RBX: ffff88806c44ac78 RCX: ffff88802e41bd00 RDX: 0000000000000000 RSI: 00000000ffffff80 RDI: 0000000000000001 RBP: 00000000ffffff80 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52000680f8c R12: dffffc0000000000 R13: 1ffff1100d889597 R14: ffff88806c44abc0 R15: ffff88806c44acb8 FS: 00005555820e4500(0000) GS:ffff888125f4f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b31b63fff CR3: 0000000072c78000 CR4: 00000000003526f0 Call Trace: dput+0xe8/0x1a0 fs/dcache.c:924 __fput+0x68e/0xa70 fs/file_table.c:476 task_work_run+0x1d4/0x260 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:44 [inline] exit_to_user_mode_loop+0xff/0x4f0 kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] do_syscall_64+0x2e3/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4966f8f749 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffc01c51258 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 000000000001a7a1 RCX: 00007f4966f8f749 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000201c5154f R10: 0000001b30f20000 R11: 0000000000000246 R12: 00007f49671e5fac R13: 00007f49671e5fa0 R14: ffffffffffffffff R15: 0000000000000004 --- 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