netdev - [syzbot] [net?] BUG: unable to handle kernel NULL pointer dereference in pc_clock

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Message-ID: <690256f3.050a0220.32483.0219.GAE@google.com>
Date: Wed, 29 Oct 2025 11:03:31 -0700
From: syzbot <syzbot+a546141ca6d53b90aba3@...kaller.appspotmail.com>
To: andrew+netdev@...n.ch, davem@...emloft.net, edumazet@...gle.com, 
	kuba@...nel.org, linux-kernel@...r.kernel.org, netdev@...r.kernel.org, 
	pabeni@...hat.com, richardcochran@...il.com, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [net?] BUG: unable to handle kernel NULL pointer dereference
 in pc_clock_settime

Hello,

syzbot found the following issue on:

HEAD commit:    b98c94eed4a9 arm64: mte: Do not warn if the page is alread..
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=11260e14580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=158bd6857eb7a550
dashboard link: https://syzkaller.appspot.com/bug?extid=a546141ca6d53b90aba3
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
userspace arch: arm64

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/2c82e514449b/disk-b98c94ee.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a322ed38c368/vmlinux-b98c94ee.xz
kernel image: https://storage.googleapis.com/syzbot-assets/059db7d7114e/Image-b98c94ee.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a546141ca6d53b90aba3@...kaller.appspotmail.com

Unable to handle kernel NULL pointer dereferenc
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
Mem abort info:
  ESR = 0x0000000086000006
  EC = 0x21: IABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x06: level 2 translation fault
user pgtable: 4k pages, 48-bit VAs, pgdp=0000000133ddc000
[0000000000000000] pgd=0800000105883403, p4d=0800000105883403, pud=0800000127709403, pmd=0000000000000000
Internal error: Oops: 0000000086000006 [#1]  SMP
Modules linked in:
CPU: 1 UID: 0 PID: 7008 Comm: syz.4.69 Not tainted syzkaller #0 PREEMPT 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025
pstate: 83400805 (Nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=-c)
pc : 0x0
lr : ptp_clock_settime+0x148/0x264 drivers/ptp/ptp_clock.c:107
sp : ffff8000a2957c40
x29: ffff8000a2957c40 x28: ffff0000cbad5c40 x27: 00000000fffffffb
x26: 1fffe0001975ab88 x25: 000000003b9aca00 x24: dfff800000000000
x23: 00000001ed5d7404 x22: 0000000000989680 x21: 0000000000000000
x20: ffff0000cca30600 x19: ffff8000a2957d00 x18: 00000000ffffffff
x17: ffff800093305000 x16: ffff800082de95c8 x15: 0000000000000001
x14: 1ffff0001452af70 x13: 0000000000000000 x12: 0000000000000000
x11: ffff70001452af71 x10: 0000000000ff0100 x9 : 0000000000000000
x8 : 0000000000000000 x7 : ffff8000877add70 x6 : 0000000000000000
x5 : ffff800093586d90 x4 : 0000000000000002 x3 : ffff80008adffef8
x2 : 0000000000000001 x1 : ffff8000a2957d00 x0 : ffff0000cca30600
Call trace:
 0x0 (P)
 pc_clock_settime+0x224/0x298 kernel/time/posix-clock.c:304
 __do_sys_clock_settime kernel/time/posix-timers.c:1131 [inline]
 __se_sys_clock_settime kernel/time/posix-timers.c:1115 [inline]
 __arm64_sys_clock_settime+0x208/0x254 kernel/time/posix-timers.c:1115
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x1e0/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:746
 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:765
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596
---[ end trace 0000000000000000 ]---


---
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