[v6.6] INFO: rcu detected stall in khugepaged

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 924b4a879cbb Linux 6.6.142
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=170c44ae580000
kernel config: https://syzkaller.appspot.com/x/.config?x=90249d2d52c08134
dashboard link: https://syzkaller.appspot.com/bug?extid=5b7e641d9594d1aa0abf
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/bd13425862f1/disk-924b4a87.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/eaa5de9e440b/vmlinux-924b4a87.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5a9aa3293c15/bzImage-924b4a87.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5b7e64...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P35/1:b..l
rcu: (detected by 1, t=10503 jiffies, g=36033, q=759404 ncpus=2)
task:khugepaged state:R running task stack:26888 pid:35 ppid:2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x1553/0x45a0 kernel/sched/core.c:6700
preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7010
irqentry_exit+0x67/0x70 kernel/entry/common.c:438
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:strscpy+0x4b/0x1c0 lib/string.c:178
Code: 48 81 fa ff ff ff 7f 0f 87 76 01 00 00 49 89 f4 48 89 fb 48 ba 00 00 00 00 00 fc ff df 45 31 ed 49 83 ff 08 0f 83 94 00 00 00 <4c> 01 eb 4d 01 ec 45 31 f6 4d 39 f7 0f 84 ca 00 00 00 4b 8d 3c 34
RSP: 0018:ffffc90000abf430 EFLAGS: 00000297
RAX: 1ffff110034ba2d1 RBX: ffff88801a5d1688 RCX: fefefefefefefeff
RDX: dffffc0000000000 RSI: ffff88801ca744b0 RDI: ffff88801a5d1688
RBP: 0000000000000000 R08: ffff88801a5d161f R09: 1ffff110034ba2c3
R10: dffffc0000000000 R11: ffffed10034ba2c4 R12: ffff88801ca744b0
R13: 0000000000000008 R14: 676170656775686b R15: 0000000000000003
strscpy include/linux/fortify-string.h:358 [inline]
__set_page_owner_handle+0x22f/0x3c0 mm/page_owner.c:177
__set_page_owner+0x45/0x60 mm/page_owner.c:197
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x1c1/0x200 mm/page_alloc.c:1581
prep_new_page mm/page_alloc.c:1588 [inline]
get_page_from_freelist+0x1951/0x19e0 mm/page_alloc.c:3220
__alloc_pages+0x1f0/0x460 mm/page_alloc.c:4500
__folio_alloc+0x10/0x20 mm/page_alloc.c:4532
alloc_charge_folio+0x47b/0xbf0 mm/khugepaged.c:1052
collapse_huge_page mm/khugepaged.c:1097 [inline]
hpage_collapse_scan_pmd+0x1797/0x3ff0 mm/khugepaged.c:1393
khugepaged_scan_mm_slot mm/khugepaged.c:2411 [inline]
khugepaged_do_scan mm/khugepaged.c:2499 [inline]
khugepaged+0x921/0x15d0 mm/khugepaged.c:2555
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</TASK>


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