VFS: Close: file count is zero (use-after-free) (2)

Status: upstream: reported C repro on 2026/08/09 05:17
Subsystems: fs
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+592c653b056459925299@syzkaller.appspotmail.com
First crash: 11d, last: 4h47m
▶ ▼ ✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision
53c291d5 patching 💥 VFS: Close: file count is zero (use-after-free) (2) 2026/08/10 07:36 2026/08/10 07:36 2026/08/10 09:15 5d63f80b
2949a68b assessment-security DenialOfService: ✅ Exploitable: ✅ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ VFS: Close: file count is zero (use-after-free) (2) 2026/08/01 00:09 2026/08/01 00:09 2026/08/01 01:03 7664cf44
▶ ▼ Discussions (2)
Title Replies (including bot) Last reply
[syzbot] Monthly fs report (Aug 2026) 0 (1) 2026/08/11 04:32
[syzbot] [fs?] VFS: Close: file count is zero (use-after-free) (2) 0 (2) 2026/08/10 06:51
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream VFS: Close: file count is zero (use-after-free) squashfs 2 syz, C done 16 786d 799d 0/29 auto-obsoleted due to no activity on 2024/07/25 12:57

Sample crash report:
 slab filp start ffff888033275800 pointer offset 0 size 408
VFS: Close: file count is 0 (f_op=snd_ctl_f_ops)
------------[ cut here ]------------
kernel BUG at fs/open.c:1466!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 1 UID: 0 PID: 5880 Comm: syz.0.18 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:filp_flush+0x18d/0x190 fs/open.c:1464
Code: 88 00 00 00 48 89 d8 48 c1 e8 03 42 80 3c 20 00 74 08 48 89 df e8 73 d3 f2 ff 48 8b 33 48 c7 c7 80 c8 7d 8b e8 d4 f4 ea fe 90 <0f> 0b 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e
RSP: 0018:ffffc90003a676b8 EFLAGS: 00010246
RAX: 0000000000000030 RBX: ffff888033275888 RCX: b521ca7f9c659c00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90003a677d8 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed10170e4903 R12: dffffc0000000000
R13: ffff888011c72520 R14: 0000000000000000 R15: 0000000000000003
FS:  000055557f931500(0000) GS:ffff888125d46000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f37c2530000 CR3: 0000000046dec000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 filp_close+0x1d/0x40 fs/open.c:1484
 gaudio_close_snd_dev drivers/usb/gadget/function/u_uac1_legacy.c:263 [inline]
 gaudio_cleanup+0x54/0xf0 drivers/usb/gadget/function/u_uac1_legacy.c:305
 f_audio_bind+0x4a0/0x630 drivers/usb/gadget/function/f_uac1_legacy.c:792
 usb_add_function+0x290/0x930 drivers/usb/gadget/composite.c:333
 configfs_composite_bind+0xde0/0x1410 drivers/usb/gadget/configfs.c:1802
 gadget_bind_driver+0x2ca/0x9e0 drivers/usb/gadget/udc/core.c:1662
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x254/0xae0 drivers/base/dd.c:706
 __driver_probe_device+0x1e8/0x360 drivers/base/dd.c:868
 driver_probe_device+0x4f/0x240 drivers/base/dd.c:898
 __driver_attach+0x339/0x600 drivers/base/dd.c:1292
 bus_for_each_dev+0x23e/0x2c0 drivers/base/bus.c:383
 bus_add_driver+0x348/0x670 drivers/base/bus.c:763
 driver_register+0x23a/0x320 drivers/base/driver.c:174
 usb_gadget_register_driver_owner+0xf9/0x270 drivers/usb/gadget/udc/core.c:1752
 gadget_dev_desc_UDC_store+0x1c9/0x2f0 drivers/usb/gadget/configfs.c:300
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x33a/0x430 fs/configfs/file.c:229
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x61e/0xbb0 fs/read_write.c:687
 ksys_write+0x156/0x270 fs/read_write.c:739
 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: 0033:0x7f37c265e0d9
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:00007ffd87364a38 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f37c28e5fa0 RCX: 00007f37c265e0d9
RDX: 000000000000000c RSI: 0000200000000400 RDI: 0000000000000003
RBP: 00007f37c26f5024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f37c28e5fac R14: 00007f37c28e5fa0 R15: 00007f37c28e5fa0
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:filp_flush+0x18d/0x190 fs/open.c:1464
Code: 88 00 00 00 48 89 d8 48 c1 e8 03 42 80 3c 20 00 74 08 48 89 df e8 73 d3 f2 ff 48 8b 33 48 c7 c7 80 c8 7d 8b e8 d4 f4 ea fe 90 <0f> 0b 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e
RSP: 0018:ffffc90003a676b8 EFLAGS: 00010246
RAX: 0000000000000030 RBX: ffff888033275888 RCX: b521ca7f9c659c00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90003a677d8 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed10170e4903 R12: dffffc0000000000
R13: ffff888011c72520 R14: 0000000000000000 R15: 0000000000000003
FS:  000055557f931500(0000) GS:ffff888125d46000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f37c2530000 CR3: 0000000046dec000 CR4: 00000000003526f0

Crashes (16):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/11 02:08 upstream d58772d8520c 508909ea .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-upstream-fs VFS: Close: file count is zero (use-after-free)
2026/08/10 06:50 upstream db2ddb871435 5d63f80b .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream VFS: Close: file count is zero (use-after-free)
2026/08/09 05:16 upstream 06cf61899d64 5d63f80b .config console log report syz / log [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream VFS: Close: file count is zero (use-after-free)
2026/08/10 00:39 upstream b643e495ae92 5d63f80b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root VFS: Close: file count is zero (use-after-free)
2026/08/07 15:41 upstream f9a2394a2348 e4ef95d6 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root VFS: Close: file count is zero (use-after-free)
2026/08/07 06:16 upstream fcaeecb8b0cd c38879ea .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root VFS: Close: file count is zero (use-after-free)
2026/08/06 21:58 upstream fcaeecb8b0cd cc56899a .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root VFS: Close: file count is zero (use-after-free)
2026/08/05 06:43 upstream 562bfb501c54 52aa2820 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root VFS: Close: file count is zero (use-after-free)
2026/08/05 04:38 upstream 562bfb501c54 52aa2820 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root VFS: Close: file count is zero (use-after-free)
2026/08/05 02:14 upstream 562bfb501c54 52aa2820 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root VFS: Close: file count is zero (use-after-free)
2026/08/04 10:03 upstream 848acc8ffe1b 9451e17e .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root VFS: Close: file count is zero (use-after-free)
2026/08/03 04:03 upstream bd1dde877520 e611ffe1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root VFS: Close: file count is zero (use-after-free)
2026/07/31 05:07 upstream e05b559f9cda aaffb173 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root VFS: Close: file count is zero (use-after-free)
2026/07/30 17:15 upstream 11028ab62899 0a1bc234 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root VFS: Close: file count is zero (use-after-free)
2026/07/31 15:58 upstream 8ba098e6b6ff db462e94 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 VFS: Close: file count is zero (use-after-free)
2026/07/30 10:29 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master fc46aed51f62 2377cd3d .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm32 VFS: Close: file count is zero (use-after-free)
* Struck through repros no longer work on HEAD.