[moderation] [kernel?] BUG: unable to handle kernel NULL pointer dereference in deactivate_slab (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: fec734e8d564 Merge tag 'riscv-for-linus-v6.17-rc8' of git:..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1404b2e2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f5b21423ca3f0a96
dashboard link: https://syzkaller.appspot.com/bug?extid=805668f2653c57255273
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
CC: [b...@alien8.de dave....@linux.intel.com h...@zytor.com linux-...@vger.kernel.org mi...@redhat.com tg...@linutronix.de x...@kernel.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/48c4501294d0/disk-fec734e8.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/676541d0dae1/vmlinux-fec734e8.xz
kernel image: https://storage.googleapis.com/syzbot-assets/17081d19c70e/bzImage-fec734e8.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+805668...@syzkaller.appspotmail.com

BUG: kernel NULL pointer dereference, address: 0000000000000001
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: Oops: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 977 Comm: kworker/0:2 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: slub_flushwq flush_cpu_slab
RIP: 0010:PagePoisoned include/linux/page-flags.h:335 [inline]
RIP: 0010:page_to_nid include/linux/mm.h:1516 [inline]
RIP: 0010:folio_nid include/linux/mm.h:1522 [inline]
RIP: 0010:slab_nid mm/slab.h:177 [inline]
RIP: 0010:deactivate_slab+0x1e/0x3f0 mm/slub.c:3109
Code: 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57 41 56 41 55 41 54 53 48 83 ec 48 49 89 f7 65 48 8b 05 97 c9 e2 0f 48 89 44 24 40 <48> 8b 06 48 83 f8 ff 0f 84 9e 03 00 00 49 89 d5 49 89 fc 48 c1 e8
RSP: 0018:ffffc900048af9d0 EFLAGS: 00010282
RAX: bb2db7d1442f0800 RBX: ffff88803c71b8c0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff88803c71b8c0
RBP: ffffc900048afc70 R08: ffffffff8f1d6237 R09: 1ffffffff1e3ac46
R10: dffffc0000000000 R11: fffffbfff1e3ac47 R12: ffffe8ffffc7ddf0
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8881268bc000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000001 CR3: 0000000036bfc000 CR4: 00000000003526f0
Call Trace:
<TASK>
flush_slab mm/slub.c:3329 [inline]
flush_cpu_slab+0xc6/0x1c0 mm/slub.c:3375
process_one_work kernel/workqueue.c:3236 [inline]
process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3319
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Modules linked in:
CR2: 0000000000000001
---[ end trace 0000000000000000 ]---
RIP: 0010:PagePoisoned include/linux/page-flags.h:335 [inline]
RIP: 0010:page_to_nid include/linux/mm.h:1516 [inline]
RIP: 0010:folio_nid include/linux/mm.h:1522 [inline]
RIP: 0010:slab_nid mm/slab.h:177 [inline]
RIP: 0010:deactivate_slab+0x1e/0x3f0 mm/slub.c:3109
Code: 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57 41 56 41 55 41 54 53 48 83 ec 48 49 89 f7 65 48 8b 05 97 c9 e2 0f 48 89 44 24 40 <48> 8b 06 48 83 f8 ff 0f 84 9e 03 00 00 49 89 d5 49 89 fc 48 c1 e8
RSP: 0018:ffffc900048af9d0 EFLAGS: 00010282
RAX: bb2db7d1442f0800 RBX: ffff88803c71b8c0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff88803c71b8c0
RBP: ffffc900048afc70 R08: ffffffff8f1d6237 R09: 1ffffffff1e3ac46
R10: dffffc0000000000 R11: fffffbfff1e3ac47 R12: ffffe8ffffc7ddf0
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8881268bc000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000001 CR3: 0000000036bfc000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
0: 90 nop
1: 90 nop
2: 90 nop
3: 90 nop
4: 90 nop
5: 90 nop
6: 90 nop
7: 90 nop
8: 90 nop
9: 90 nop
a: 90 nop
b: 90 nop
c: 55 push %rbp
d: 41 57 push %r15
f: 41 56 push %r14
11: 41 55 push %r13
13: 41 54 push %r12
15: 53 push %rbx
16: 48 83 ec 48 sub $0x48,%rsp
1a: 49 89 f7 mov %rsi,%r15
1d: 65 48 8b 05 97 c9 e2 mov %gs:0xfe2c997(%rip),%rax # 0xfe2c9bc
24: 0f
25: 48 89 44 24 40 mov %rax,0x40(%rsp)
* 2a: 48 8b 06 mov (%rsi),%rax <-- trapping instruction
2d: 48 83 f8 ff cmp $0xffffffffffffffff,%rax
31: 0f 84 9e 03 00 00 je 0x3d5
37: 49 89 d5 mov %rdx,%r13
3a: 49 89 fc mov %rdi,%r12
3d: 48 rex.W
3e: c1 .byte 0xc1
3f: e8 .byte 0xe8


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