INFO: rcu detected stall in hugetlbfs_file

Kernel	Title	Rank 🛈	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
linux-4.19	INFO: rcu detected stall in hugetlbfs_file_mmap	1				6	1623d	1721d	0/1	auto-closed as invalid on 2021/09/03 15:56
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P11698/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=58425, q=210 ncpus=2)
task:syz.4.1524      state:R  running task     stack:25928 pid:11698 tgid:11696 ppid:5855   task_flags:0x400040 flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7288
 irqentry_exit+0x6f/0x90 kernel/entry/common.c:197
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:strnlen+0x3a/0x90 lib/string.c:432
Code: f8 48 85 f6 74 5e 4c 8d 34 37 49 bf 00 00 00 00 00 fc ff df 48 89 fb 48 89 f8 48 89 d9 48 c1 e9 03 42 0f b6 0c 39 84 c9 75 12 <80> 38 00 74 35 48 ff c0 48 ff c3 48 ff ce 75 e0 eb 25 89 da 80 e2
RSP: 0018:ffffc900040cee68 EFLAGS: 00000246
RAX: ffff8880264b44c3 RBX: ffff8880264b44c3 RCX: 0000000000000000
RDX: 0000000000000002 RSI: 000000000000000d RDI: ffff8880264b44c0
RBP: ffff88801cded1b0 R08: ffff88801cded167 R09: 1ffff110039bda2c
R10: dffffc0000000000 R11: ffffed10039bda2d R12: 0000000000000009
R13: 000000000000009f R14: ffff8880264b44d0 R15: dffffc0000000000
 strnlen include/linux/fortify-string.h:233 [inline]
 sized_strscpy include/linux/fortify-string.h:309 [inline]
 __update_page_owner_handle+0x2a7/0x570 mm/page_owner.c:253
 __set_page_owner+0x10b/0x4a0 mm/page_owner.c:330
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1851
 prep_new_page mm/page_alloc.c:1859 [inline]
 get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3858
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5148
 alloc_buddy_hugetlb_folio+0xdf/0x1c0 mm/hugetlb.c:1965
 only_alloc_fresh_hugetlb_folio+0x8c/0x280 mm/hugetlb.c:2001
 alloc_surplus_hugetlb_folio+0x103/0x430 mm/hugetlb.c:2244
 gather_surplus_pages mm/hugetlb.c:2434 [inline]
 hugetlb_acct_memory+0x59f/0x1050 mm/hugetlb.c:5317
 hugetlb_reserve_pages+0x831/0xec0 mm/hugetlb.c:7328
 hugetlbfs_file_mmap+0x490/0x680 fs/hugetlbfs/inode.c:153
 vfs_mmap include/linux/fs.h:2289 [inline]
 mmap_file mm/internal.h:167 [inline]
 __mmap_new_file_vma mm/vma.c:2413 [inline]
 __mmap_new_vma mm/vma.c:2476 [inline]
 __mmap_region mm/vma.c:2669 [inline]
 mmap_region+0x18ae/0x20c0 mm/vma.c:2739
 do_mmap+0xc45/0x10d0 mm/mmap.c:558
 vm_mmap_pgoff+0x2a6/0x4d0 mm/util.c:580
 ksys_mmap_pgoff+0x587/0x760 mm/mmap.c:604
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f931318eb69
RSP: 002b:00007f9313fcc038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f93133b5fa0 RCX: 00007f931318eb69
RDX: 000000000000000b RSI: 0000000000c00000 RDI: 0000200000400000
RBP: 00007f9313211df1 R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000059032 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f93133b5fa0 R15: 00007ffcdad56d58
 </TASK>
rcu: rcu_preempt kthread starved for 9649 jiffies! g58425 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:R  running task     stack:27160 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
 __schedule_loop kernel/sched/core.c:7043 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7058
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
 kthread+0x70e/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.16.0-next-20250731-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: 53 e8 02 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d d3 06 11 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90000197de0 EFLAGS: 000002c6
RAX: c74c6a3740c5be00 RBX: ffffffff81968308 RCX: c74c6a3740c5be00
RDX: 0000000000000001 RSI: ffffffff8d98c137 RDI: ffffffff8be34100
RBP: ffffc90000197f20 R08: ffff8880b8732f5b R09: 1ffff110170e65eb
R10: dffffc0000000000 R11: ffffed10170e65ec R12: ffffffff8fa21830
R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff11003a58b40
FS:  0000000000000000(0000) GS:ffff888125d43000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f07c673ff98 CR3: 000000001dec6000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:757
 default_idle_call+0x74/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:190 [inline]
 do_idle+0x1e8/0x510 kernel/sched/idle.c:330
 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428
 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:315
 common_startup_64+0x13e/0x147
 </TASK>