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Internal error in timerfd_read

Status: upstream: reported C repro on 2025/08/12 13:38
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+3f83fe607740b0f826e8@syzkaller.appspotmail.com
First crash: 165d, last: 54d
Fix bisection: failed (error log, bisect log)
  
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2025/08/17 linux-5.15.y (ToT) c79648372d02 C [report] Internal error in timerfd_read
2025/08/17 upstream (ToT) 99bade344cfa C Didn't crash
▶ ▼ Last patch testing requests (1)
Created Duration User Patch Repo Result
2025/12/01 04:47 47m retest repro linux-5.15.y report log
▶ ▼ Fix bisection attempts (5)
Created Duration User Patch Repo Result
2026/01/22 19:48 1m fix candidate upstream error job log
2025/12/18 13:24 8m fix candidate upstream error job log
2025/11/17 16:20 4m fix candidate upstream error job log
2025/09/29 13:16 5m fix candidate upstream error job log
2025/09/22 03:24 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: 1 PID: 4226 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 : timerfd_read+0x5d4/0x730 fs/timerfd.c:316
lr : __uaccess_mask_ptr arch/arm64/include/asm/uaccess.h:244 [inline]
lr : timerfd_read+0x5b4/0x730 fs/timerfd.c:316
sp : ffff80001f7c79c0
x29: ffff80001f7c7a80 x28: dfff800000000000 x27: ffff700003ef8f3c
x26: 0000000020000140 x25: 0000000000000005 x24: ffff0000ecb010e4
x23: ffff0000ecb010d8 x22: 0000000201ed6b2a x21: 0000000000400140
x20: 0000000000000001 x19: 00000000fffffff2 x18: 0000000000000003
x17: 0000000000000000 x16: ffff800008a05628 x15: 0000000000000003
x14: 0000000000ff0100 x13: 1ffff0000282e06b x12: 0000000000ff0100
x11: 0000000000000000 x10: 0000000020000140 x9 : 0000ffffffffffff
x8 : 0000000020000140 x7 : ffff800008750ed4 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000001
x2 : 0000000000000008 x1 : 0000000000000001 x0 : 0000000000000000
Call trace:
 timerfd_read+0x5d4/0x730 fs/timerfd.c:316
 vfs_read+0x278/0xa10 fs/read_write.c:483
 ksys_read+0x120/0x210 fs/read_write.c:623
 __do_sys_read fs/read_write.c:633 [inline]
 __se_sys_read fs/read_write.c:631 [inline]
 __arm64_sys_read+0x7c/0x90 fs/read_write.c:631
 __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: d503229f 2a1f03f3 2a1f03e0 f8000956 (2a1303e1) 
---[ end trace 508172c16cad07e2 ]---
----------------
Code disassembly (best guess):
   0:	d503229f 	csdb
   4:	2a1f03f3 	mov	w19, wzr
   8:	2a1f03e0 	mov	w0, wzr
   c:	f8000956 	sttr	x22, [x10]
* 10:	2a1303e1 	mov	w1, w19 <-- trapping instruction

Crashes (15):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/13 19:02 linux-5.15.y c79648372d02 22ec1469 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 Internal error in timerfd_read
2025/08/14 04:52 linux-5.15.y c79648372d02 22ec1469 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 Internal error in timerfd_read
2025/08/14 04:50 linux-5.15.y c79648372d02 22ec1469 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 Internal error in timerfd_read
2025/08/14 04:48 linux-5.15.y c79648372d02 22ec1469 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 Internal error in timerfd_read
2025/08/14 04:46 linux-5.15.y c79648372d02 22ec1469 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 Internal error in timerfd_read
2025/08/14 02:36 linux-5.15.y c79648372d02 22ec1469 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 Internal error in timerfd_read
2025/08/14 02:35 linux-5.15.y c79648372d02 22ec1469 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 Internal error in timerfd_read
2025/08/13 07:58 linux-5.15.y c79648372d02 22ec1469 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 Internal error in timerfd_read
2025/08/13 07:58 linux-5.15.y c79648372d02 22ec1469 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 Internal error in timerfd_read
2025/08/13 05:14 linux-5.15.y c79648372d02 22ec1469 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 Internal error in timerfd_read
2025/08/13 05:13 linux-5.15.y c79648372d02 22ec1469 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 Internal error in timerfd_read
2025/08/12 13:42 linux-5.15.y c79648372d02 c06e8995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 Internal error in timerfd_read
2025/08/12 13:40 linux-5.15.y c79648372d02 c06e8995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 Internal error in timerfd_read
2025/08/12 13:38 linux-5.15.y c79648372d02 c06e8995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 Internal error in timerfd_read
2025/08/12 13:37 linux-5.15.y c79648372d02 c06e8995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 Internal error in timerfd_read
* Struck through repros no longer work on HEAD.