syzbot


KASAN: vmalloc-out-of-bounds Write in irq_work_single

Status: moderation: reported on 2025/10/03 09:44
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+b4bb939c0f22f6cc80fa@syzkaller.appspotmail.com
First crash: 4d16h, last: 4d16h

Sample crash report:
==================================================================
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
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/09/29 09:38 upstream e5f0a698b34e 001c9061 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: vmalloc-out-of-bounds Write in irq_work_single
* Struck through repros no longer work on HEAD.