[syzbot] [trace?] BUG: unable to handle kernel paging request in __ftrace_set_clr_event_nolock

[syzbot] [trace?] BUG: unable to handle kernel paging request in __ftrace_set_clr_event_nolock

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    ba5cc80fd326 Merge branch 'for-next/core' into for-kernelci
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=10a75079580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=ccf4bea59f67007
dashboard link: https://syzkaller.appspot.com/bug?extid=4d3143c8e28f6266c636
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
userspace arch: arm64

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/959ad5f4e730/disk-ba5cc80f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/0787d25f251e/vmlinux-ba5cc80f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2e85c36fabac/Image-ba5cc80f.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4d3143c8e28f6266c636@syzkaller.appspotmail.com

Unable to handle kernel paging request at virtual address dfff800000000000
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
Mem abort info:
  ESR = 0x0000000096000005
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x05: level 1 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000
  CM = 0, WnR = 0, TnD = 0, TagAccess = 0
  GCS = 0, Overlay = 0, DirtyBit = 0
[dfff800000000000] address between user and kernel address ranges
Internal error: Oops: 0000000096000005 [#1]  SMP
Instance 9�G\x1e�̌83��s]t4	��Ķy�G\x18|aJ� ��VF��8V$m��7To0FO�P�p\x1e��6�O\f%�DZ�rf0 not found
Modules linked in:
CPU: 1 UID: 0 PID: 15930 Comm: syz.7.4873 Tainted: G             L      syzkaller #0 PREEMPT 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/02/2026
pstate: 83400005 (Nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : strcmp+0x28/0xf0 lib/string.c:265
lr : remove_cache_mod kernel/trace/trace_events.c:948 [inline]
lr : cache_mod kernel/trace/trace_events.c:977 [inline]
lr : __ftrace_set_clr_event_nolock+0x6a0/0x940 kernel/trace/trace_events.c:1395
sp : ffff800093567840
x29: ffff800093567870 x28: dfff800000000000 x27: 0000000000000000
x26: ffff800088d6e8b0 x25: ffff0000c71e0580 x24: 00000000ffffffea
x23: ffff800088d6e8b0 x22: 0000000000000000 x21: dfff800000000000
x20: ffff0000c71e0598 x19: ffff0000d4e7e4a0 x18: 0000000000000000
x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000001
x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000
x11: 0000000000000000 x10: dfff800000000000 x9 : ffff0000d2e90f01
x8 : 0000000000000000 x7 : ffff800080538ea0 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000000 x3 : ffff8000806c6790
x2 : 0000000000000000 x1 : ffff0000d2e90f01 x0 : 0000000000000000
Call trace:
 strcmp+0x28/0xf0 lib/string.c:265 (P)
 remove_cache_mod kernel/trace/trace_events.c:948 [inline]
 cache_mod kernel/trace/trace_events.c:977 [inline]
 __ftrace_set_clr_event_nolock+0x6a0/0x940 kernel/trace/trace_events.c:1395
 __ftrace_set_clr_event+0xa8/0xec kernel/trace/trace_events.c:1410
 ftrace_set_clr_event+0x2a0/0x438 kernel/trace/trace_events.c:1460
 ftrace_event_write+0x1dc/0x28c kernel/trace/trace_events.c:1548
 vfs_write+0x2a4/0xa0c fs/read_write.c:685
 ksys_write+0x12c/0x228 fs/read_write.c:739
 __do_sys_write fs/read_write.c:750 [inline]
 __se_sys_write fs/read_write.c:747 [inline]
 __arm64_sys_write+0x84/0x98 fs/read_write.c:747
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121
 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140
 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:738
 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:757
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:590
Code: aa0103e9 f2fbffea d343fc0b 1200080c (38ea696b) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	aa0103e9 	mov	x9, x1
   4:	f2fbffea 	movk	x10, #0xdfff, lsl #48
   8:	d343fc0b 	lsr	x11, x0, #3
   c:	1200080c 	and	w12, w0, #0x7
* 10:	38ea696b 	ldrsb	w11, [x11, x10] <-- trapping instruction


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