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

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Message-ID: <68fd58db.050a0220.32483.0009.GAE@google.com>
Date: Sat, 25 Oct 2025 16:10:19 -0700
From: syzbot <syzbot+c8c0e7ccabd456541612@...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_gettime

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=1337c258580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=158bd6857eb7a550
dashboard link: https://syzkaller.appspot.com/bug?extid=c8c0e7ccabd456541612
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+c8c0e7ccabd456541612@...kaller.appspotmail.com

loop5: detected capacity change from 0 to 128
EXT4-fs (loop5): mounted filesystem 76b65be2-f6da-4727-8c75-0525a5b65a09 r/w without journal. Quota mode: none.
Unable to handle kernel NULL pointer dereference at virtual 
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=00000001274b4000
[0000000000000000] pgd=0800000119171403, p4d=0800000119171403, pud=080000010c419403, pmd=0000000000000000
Internal error: Oops: 0000000086000006 [#1]  SMP
Modules linked in:
CPU: 1 UID: 0 PID: 9258 Comm: syz.5.429 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_gettime+0xa4/0xb8 drivers/ptp/ptp_clock.c:118
sp : ffff80009c077c70
x29: ffff80009c077c70 x28: ffff0000fabb8000 x27: fffffffffffffffb
x26: 1fffe0001f577000 x25: ffff80008aedca60 x24: ffff80009c077ce0
x23: dfff800000000000 x22: dfff800000000000 x21: 0000000000000000
x20: ffff0000cc206400 x19: ffff80009c077d00 x18: 0000000000000000
x17: 0000000000000000 x16: ffff800082de95c8 x15: 0000000000000001
x14: 1fffe0001996ac19 x13: 0000000000000000 x12: 0000000000000000
x11: 0000000000080000 x10: 00000000000000eb x9 : ffff8000a5059000
x8 : 0000000000000000 x7 : ffff800080653180 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000001 x3 : ffff80008ae046c4
x2 : 0000000000000001 x1 : ffff80009c077d00 x0 : ffff0000cc206400
Call trace:
 0x0 (P)
 pc_clock_gettime+0x148/0x1a8 kernel/time/posix-clock.c:258
 __do_sys_clock_gettime kernel/time/posix-timers.c:1144 [inline]
 __se_sys_clock_gettime kernel/time/posix-timers.c:1134 [inline]
 __arm64_sys_clock_gettime+0x1b4/0x248 kernel/time/posix-timers.c:1134
 __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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