Internal error in fanotify_ioctl

Status: upstream: reported C repro on 2025/08/22 02:54
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+6a9bf2c15fdbea1c3906@syzkaller.appspotmail.com
First crash: 370d, last: 32d
Fix bisection: failed (error log, bisect log)
  
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2025/08/23 linux-5.15.y (ToT) c79648372d02 C [report] Internal error in fanotify_ioctl
2025/08/23 upstream (ToT) 52025b8fc992 C Didn't crash
▶ ▼ Last patch testing requests (4)
Created Duration User Patch Repo Result
2026/07/25 16:24 16m retest repro linux-5.15.y report log
2026/05/05 19:19 16m retest repro linux-5.15.y report log
2026/02/17 01:18 11m retest repro linux-5.15.y report log
2025/12/08 23:57 11m retest repro linux-5.15.y report log
▶ ▼ Fix bisection attempts (6)
Created Duration User Patch Repo Result
2026/06/28 20:39 16m fix candidate upstream error job log
2026/03/28 10:35 1m fix candidate upstream error job log
2026/02/25 09:55 1m fix candidate upstream error job log
2026/01/26 03:34 1m fix candidate upstream error job log
2025/12/26 09:33 3m fix candidate upstream error job log
2025/09/27 21:41 0m bisect fix linux-5.15.y error job log

Sample crash report:
Internal error: Oops - BTI: 0000000036000001 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 4261 Comm: syz.0.17 Not tainted 5.15.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025
pstate: 42400405 (nZcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=jc)
pc : fanotify_ioctl+0x184/0x1d4 fs/notify/fanotify/fanotify_user.c:929
lr : sign_extend64 include/linux/bitops.h:183 [inline]
lr : __uaccess_mask_ptr arch/arm64/include/asm/uaccess.h:244 [inline]
lr : fanotify_ioctl+0x168/0x1d4 fs/notify/fanotify/fanotify_user.c:925
sp : ffff80001f7f79b0
x29: ffff80001f7f79c0 x28: dfff800000000000 x27: ffff700003efef48
x26: 1fffe0001b298000 x25: ffff80001f7f7a40 x24: 0000000000400140
x23: 0000000000000000 x22: dfff800000000000 x21: 0000000000000000
x20: 0000000000000001 x19: 0000000000000000 x18: 0000000000000000
x17: 0000000000000000 x16: ffff8000089f5b40 x15: 00000000c020660b
x14: 0000000000ff0100 x13: 1ffff0000282e06b x12: 0000000000ff0100
x11: 0000000000000000 x10: 0000ffffffffffff x9 : 0000000000000000
x8 : 00000000fffffff2 x7 : ffff800008750ed4 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000001
x2 : 0000000000000008 x1 : 0000000000000001 x0 : 0000000000000000
Call trace:
 fanotify_ioctl+0x184/0x1d4 fs/notify/fanotify/fanotify_user.c:925
 vfs_ioctl fs/ioctl.c:51 [inline]
 do_vfs_ioctl+0xbe0/0x2370 fs/ioctl.c:834
 __do_sys_ioctl fs/ioctl.c:872 [inline]
 __se_sys_ioctl fs/ioctl.c:860 [inline]
 __arm64_sys_ioctl+0xe4/0x1c8 fs/ioctl.c:860
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
Code: ea2a013f 9a9f026b d503229f b8000975 (93407d00) 
---[ end trace c4805a4ec8372a29 ]---
----------------
Code disassembly (best guess):
   0:	ea2a013f 	bics	xzr, x9, x10
   4:	9a9f026b 	csel	x11, x19, xzr, eq	// eq = none
   8:	d503229f 	csdb
   c:	b8000975 	sttr	w21, [x11]
* 10:	93407d00 	sxtw	x0, w8 <-- trapping instruction

Crashes (9):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/22 20:13 linux-5.15.y c79648372d02 bf27483f .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 Internal error in fanotify_ioctl
2025/08/23 02:57 linux-5.15.y c79648372d02 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 Internal error in fanotify_ioctl
2025/08/23 02:54 linux-5.15.y c79648372d02 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 Internal error in fanotify_ioctl
2025/08/23 02:44 linux-5.15.y c79648372d02 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 Internal error in fanotify_ioctl
2025/08/23 02:43 linux-5.15.y c79648372d02 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 Internal error in fanotify_ioctl
2025/08/22 02:57 linux-5.15.y c79648372d02 3e79b825 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 Internal error in fanotify_ioctl
2025/08/22 02:56 linux-5.15.y c79648372d02 3e79b825 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 Internal error in fanotify_ioctl
2025/08/22 02:53 linux-5.15.y c79648372d02 3e79b825 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 Internal error in fanotify_ioctl
2025/08/22 02:53 linux-5.15.y c79648372d02 3e79b825 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 Internal error in fanotify_ioctl
* Struck through repros no longer work on HEAD.