[moderation] [kernel?] KASAN: vmalloc-out-of-bounds Write in irq_work_single

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: e5f0a698b34e Linux 6.17
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11904334580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f5b21423ca3f0a96
dashboard link: https://syzkaller.appspot.com/bug?extid=b4bb939c0f22f6cc80fa
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
CC: [linux-...@vger.kernel.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/65c62c135cfb/disk-e5f0a698.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/140dd0458281/vmlinux-e5f0a698.xz
kernel image: https://storage.googleapis.com/syzbot-assets/56ec522db146/bzImage-e5f0a698.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b4bb93...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: vmalloc-out-of-bounds in instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
BUG: KASAN: vmalloc-out-of-bounds in atomic_cmpxchg include/linux/atomic/atomic-instrumented.h:1195 [inline]
BUG: KASAN: vmalloc-out-of-bounds in irq_work_single+0x14f/0x2b0 kernel/irq_work.c:228
Write of size 4 at addr ffffc90005dc5098 by task irq_work/1/26

CPU: 1 UID: 0 PID: 26 Comm: irq_work/1 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
<TASK>
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xca/0x240 mm/kasan/report.c:482
kasan_report+0x118/0x150 mm/kasan/report.c:595
check_region_inline mm/kasan/generic.c:-1 [inline]
kasan_check_range+0x2b0/0x2c0 mm/kasan/generic.c:189
instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
atomic_cmpxchg include/linux/atomic/atomic-instrumented.h:1195 [inline]
irq_work_single+0x14f/0x2b0 kernel/irq_work.c:228
irq_work_run_list kernel/irq_work.c:252 [inline]
run_irq_workd+0x121/0x190 kernel/irq_work.c:305
smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160
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>

The buggy address belongs to a vmalloc virtual mapping
Memory state around the buggy address:
ffffc90005dc4f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
ffffc90005dc5000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
>ffffc90005dc5080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
^
ffffc90005dc5100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
ffffc90005dc5180: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
==================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup