INFO: rcu detected stall in khugepaged

Status: upstream: reported on 2026/06/16 00:14
Reported-by: syzbot+5b7e641d9594d1aa0abf@syzkaller.appspotmail.com
First crash: 57d, last: 57d
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in khugepaged (2) mm 1 1 723d 723d 0/29 auto-obsoleted due to no activity on 2024/11/17 09:26
upstream INFO: rcu detected stall in khugepaged mm 1 1 1432d 1432d 0/29 auto-obsoleted due to no activity on 2022/12/08 19:48
upstream INFO: rcu detected stall in khugepaged (3) prio:normal mm 1 33 6d01h 7d12h 0/29 upstream: reported on 2026/08/05 00:01

Sample crash report:
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>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/06/16 00:13 linux-6.6.y 924b4a879cbb 50bb0618 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in khugepaged
* Struck through repros no longer work on HEAD.