KASAN: out-of-bounds Write in dup_task_struct

Status: premoderation: reported on 2026/09/03 14:39
Reported-by: syzbot+7ee019af823d6c081a4a@syzkaller.appspotmail.com
First crash: 18d, last: 18d

Sample crash report:
==================================================================
BUG: KASAN: out-of-bounds in kasan_save_stack mm/kasan/common.c:35 [inline]
BUG: KASAN: out-of-bounds in kasan_set_track mm/kasan/common.c:45 [inline]
BUG: KASAN: out-of-bounds in set_alloc_info mm/kasan/common.c:430 [inline]
BUG: KASAN: out-of-bounds in __kasan_slab_alloc+0xa8/0xe0 mm/kasan/common.c:463
Write of size 512 at addr ffffc90000ae77f0 by task syz-executor/271

CPU: 1 PID: 271 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 __dump_stack+0x21/0x24 lib/dump_stack.c:77
 dump_stack_lvl+0x1a7/0x208 lib/dump_stack.c:118
 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:435 [inline]
 kasan_report+0x100/0x140 mm/kasan/report.c:452
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x249/0x2a0 mm/kasan/generic.c:189
 memset+0x23/0x40 mm/kasan/shadow.c:44
 kasan_save_stack mm/kasan/common.c:35 [inline]
 kasan_set_track mm/kasan/common.c:45 [inline]
 set_alloc_info mm/kasan/common.c:430 [inline]
 __kasan_slab_alloc+0xa8/0xe0 mm/kasan/common.c:463
 kasan_slab_alloc include/linux/kasan.h:244 [inline]
 slab_post_alloc_hook+0x5d/0x2f0 mm/slab.h:580
 slab_alloc_node mm/slub.c:2952 [inline]
 slab_alloc mm/slub.c:2960 [inline]
 kmem_cache_alloc+0x15a/0x2d0 mm/slub.c:2965
 kmem_cache_alloc_node include/linux/slab.h:426 [inline]
 alloc_task_struct_node kernel/fork.c:177 [inline]
 dup_task_struct+0x57/0xbd0 kernel/fork.c:912
 copy_process+0x5dd/0x3320 kernel/fork.c:2101
 kernel_clone+0x233/0x950 kernel/fork.c:2650
 __do_sys_clone kernel/fork.c:2776 [inline]
 __se_sys_clone kernel/fork.c:2760 [inline]
 __x64_sys_clone+0x198/0x210 kernel/fork.c:2760
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f27c1bfabd2
Code: 89 e7 e8 71 8b f7 ff 45 31 c0 31 d2 31 f6 64 48 8b 04 25 10 00 00 00 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 66 89 c5 85 c0 75 3b 64 48 8b 04 25 10 00 00
RSP: 002b:00007ffc7ca22040 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007ffc7ca22040 RCX: 00007f27c1bfabd2
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 00007ffc7ca225e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000555566bd37d0 R11: 0000000000000246 R12: 0000000000000000
R13: 0000555566beb4b0 R14: 0000000000310208 R15: 0000000000000000


Memory state around the buggy address:
 ffffc90000ae7880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90000ae7900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc90000ae7980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                                                             ^
 ffffc90000ae7a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90000ae7a80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
cgroup: Unknown subsys name 'net'
cgroup: Unknown subsys name 'devices'
cgroup: Unknown subsys name 'hugetlb'
cgroup: Unknown subsys name 'rlimit'
Adding 124996k swap on ./swap-file.  Priority:0 extents:1 across:124996k 

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/03 14:39 android13-5.10-lts d1d91e95d6f1 6a988719 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: out-of-bounds Write in dup_task_struct
* Struck through repros no longer work on HEAD.