KASAN: slab-out-of-bounds Read in process_one_work

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 98555239e4c3 Merge tag 'arc-6.1-fixes' of git://git.kernel..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=167c9a32880000
kernel config: https://syzkaller.appspot.com/x/.config?x=701f2aae1cb0470e
dashboard link: https://syzkaller.appspot.com/bug?extid=83cb0411d0fcf0a30fc1
compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
CC: [ak...@linux-foundation.org big...@linutronix.de b...@vger.kernel.org bra...@kernel.org ebie...@xmission.com linux-...@vger.kernel.org tg...@linutronix.de]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5e0bf19d7c3e/disk-98555239.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/16fb10cc9d0a/vmlinux-98555239.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ef56d08e0125/bzImage-98555239.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+83cb04...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-out-of-bounds in swake_up_locked kernel/sched/swait.c:29 [inline]
BUG: KASAN: slab-out-of-bounds in complete+0xa8/0x1c0 kernel/sched/completion.c:36
Read of size 8 at addr ffff88801ffcba78 by task kworker/u4:32/11940

CPU: 0 PID: 11940 Comm: kworker/u4:32 Not tainted 6.1.0-rc2-syzkaller-00078-g98555239e4c3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
Workqueue: events_unbound call_usermodehelper_exec_work
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
print_address_description+0x74/0x340 mm/kasan/report.c:284
print_report+0x107/0x220 mm/kasan/report.c:395
kasan_report+0x139/0x170 mm/kasan/report.c:495
swake_up_locked kernel/sched/swait.c:29 [inline]
complete+0xa8/0x1c0 kernel/sched/completion.c:36
process_one_work+0x81c/0xd10 kernel/workqueue.c:2289
worker_thread+0xb14/0x1330 kernel/workqueue.c:2436
kthread+0x266/0x300 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
</TASK>

Allocated by task 2:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4c/0x70 mm/kasan/common.c:52
__kasan_slab_alloc+0x65/0x70 mm/kasan/common.c:325
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook mm/slab.h:737 [inline]
slab_alloc_node mm/slub.c:3398 [inline]
kmem_cache_alloc_node+0x1ca/0x340 mm/slub.c:3443
alloc_task_struct_node kernel/fork.c:171 [inline]
dup_task_struct+0x4e/0x490 kernel/fork.c:966
copy_process+0x637/0x3fc0 kernel/fork.c:2084
kernel_clone+0x227/0x640 kernel/fork.c:2671
kernel_thread+0x150/0x1d0 kernel/fork.c:2731
create_kthread kernel/kthread.c:399 [inline]
kthreadd+0x5bc/0x790 kernel/kthread.c:746
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306

The buggy address belongs to the object at ffff88801ffc9d40
which belongs to the cache task_struct of size 7232
The buggy address is located 248 bytes to the right of
7232-byte region [ffff88801ffc9d40, ffff88801ffcb980)

The buggy address belongs to the physical page:
page:ffffea00007ff200 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1ffc8
head:ffffea00007ff200 order:3 compound_mapcount:0 compound_pincount:0
memcg:ffff888076124f01
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 dead000000000001 ffff8881400073c0
raw: 0000000000000000 0000000000040004 00000001ffffffff ffff888076124f01
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 9, tgid 9 (kworker/u4:0), ts 6883003803, free_ts 0
prep_new_page mm/page_alloc.c:2538 [inline]
get_page_from_freelist+0x72b/0x7a0 mm/page_alloc.c:4287
__alloc_pages+0x259/0x560 mm/page_alloc.c:5554
alloc_slab_page+0x70/0xf0 mm/slub.c:1794
allocate_slab+0x5e/0x4b0 mm/slub.c:1939
new_slab mm/slub.c:1992 [inline]
___slab_alloc+0x7f4/0xeb0 mm/slub.c:3180
__slab_alloc mm/slub.c:3279 [inline]
slab_alloc_node mm/slub.c:3364 [inline]
kmem_cache_alloc_node+0x283/0x340 mm/slub.c:3443
alloc_task_struct_node kernel/fork.c:171 [inline]
dup_task_struct+0x4e/0x490 kernel/fork.c:966
copy_process+0x637/0x3fc0 kernel/fork.c:2084
kernel_clone+0x227/0x640 kernel/fork.c:2671
user_mode_thread+0x12d/0x190 kernel/fork.c:2747
call_usermodehelper_exec_work+0x57/0x220 kernel/umh.c:175
process_one_work+0x81c/0xd10 kernel/workqueue.c:2289
worker_thread+0xb14/0x1330 kernel/workqueue.c:2436
kthread+0x266/0x300 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
page_owner free stack trace missing

Memory state around the buggy address:
ffff88801ffcb900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88801ffcb980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88801ffcba00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff88801ffcba80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88801ffcbb00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================


---
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.

[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.