syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P10/1:b..l P6351/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=20973, q=662 ncpus=2)
task:syz-executor    state:R  running task     stack:19496 pid:6351  tgid:6351  ppid:6344   task_flags:0x400140 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5258 [inline]
 __schedule+0x150e/0x5070 kernel/sched/core.c:6866
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7193
 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216
 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:check_kcov_mode kernel/kcov.c:194 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:246 [inline]
RIP: 0010:__sanitizer_cov_trace_cmp8+0x37/0x90 kernel/kcov.c:294
Code: 08 b0 9f 92 65 8b 15 58 f5 dd 10 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 57 83 b9 6c 16 00 00 00 74 4e 8b 91 48 16 00 00 <83> fa 03 75 43 48 8b 91 50 16 00 00 44 8b 89 4c 16 00 00 49 c1 e1
RSP: 0018:ffffc9000b30f4e8 EFLAGS: 00000246
RAX: ffffffff823236e3 RBX: dffffc0000000000 RCX: ffff88802f5bdb80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffff8232358e R09: ffffffff8e13f2e0
R10: 0000000000000009 R11: ffffffff81ad9d50 R12: 0000000000041681
R13: 0000000000000001 R14: 0000000000000000 R15: ffff88801cc70800
 __update_page_owner_free_handle+0x183/0x470 mm/page_owner.c:284
 __reset_page_owner+0x85/0x1f0 mm/page_owner.c:321
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1406 [inline]
 free_unref_folios+0xdb3/0x14f0 mm/page_alloc.c:3000
 folios_put_refs+0x584/0x670 mm/swap.c:1002
 folio_batch_release include/linux/pagevec.h:101 [inline]
 shmem_undo_range+0x49e/0x1490 mm/shmem.c:1137
 shmem_truncate_range mm/shmem.c:1249 [inline]
 shmem_evict_inode+0x26e/0xa70 mm/shmem.c:1379
 evict+0x5f4/0xae0 fs/inode.c:837
 do_unlinkat+0x41d/0x5d0 fs/namei.c:5509
 __do_sys_unlink fs/namei.c:5540 [inline]
 __se_sys_unlink fs/namei.c:5538 [inline]
 __x64_sys_unlink+0x47/0x50 fs/namei.c:5538
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb67338ecf7
RSP: 002b:00007ffe81cc1e48 EFLAGS: 00000206 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb67338ecf7
RDX: 00007ffe81cc1e70 RSI: 00007ffe81cc1f00 RDI: 00007ffe81cc1f00
RBP: 00007ffe81cc1f00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffe81cc2f90
R13: 00007fb673413d7d R14: 000055555f4074a8 R15: 0000000000000005
 </TASK>
task:kworker/0:1     state:R  running task     stack:20992 pid:10    tgid:10    ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: events drain_vmap_area_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5258 [inline]
 __schedule+0x150e/0x5070 kernel/sched/core.c:6866
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7193
 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:__orc_find arch/x86/kernel/unwind_orc.c:110 [inline]
RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:238 [inline]
RIP: 0010:unwind_next_frame+0x2ca/0x23d0 arch/x86/kernel/unwind_orc.c:510
Code: 4a 8d 1c 82 48 83 c3 fc 49 89 d5 48 39 da 0f 86 21 02 00 00 49 29 d5 49 c1 fd 02 4a 8d 04 6d 00 00 00 00 4c 01 e8 48 8d 14 46 <48> bd 00 00 00 00 00 fc ff df e9 8f 01 00 00 31 db e9 d6 17 00 00
RSP: 0018:ffffc900000f72f8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffffff8fc23c3c RCX: ffffffff8fc23c40
RDX: ffffffff9041e414 RSI: ffffffff9041e414 RDI: ffffffff8be07900
RBP: ffffffff8fc23c40 R08: 0000000000000001 R09: ffffffff8e13f2e0
R10: ffffc900000f7418 R11: ffffffff81ad9d50 R12: ffffffff821a1f67
R13: 0000000000000000 R14: ffffc900000f73c8 R15: ffffffff8fc23c3c
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 save_stack+0xf5/0x1f0 mm/page_owner.c:165
 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:320
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1406 [inline]
 __free_frozen_pages+0xbc8/0xd30 mm/page_alloc.c:2943
 kasan_depopulate_vmalloc_pte+0x6d/0x90 mm/kasan/shadow.c:484
 apply_to_pte_range mm/memory.c:3182 [inline]
 apply_to_pmd_range mm/memory.c:3226 [inline]
 apply_to_pud_range mm/memory.c:3262 [inline]
 apply_to_p4d_range mm/memory.c:3298 [inline]
 __apply_to_page_range+0xb66/0x13d0 mm/memory.c:3334
 __kasan_release_vmalloc+0xa2/0xd0 mm/kasan/shadow.c:602
 kasan_release_vmalloc include/linux/kasan.h:593 [inline]
 kasan_release_vmalloc_node mm/vmalloc.c:2320 [inline]
 purge_vmap_node+0x214/0x8d0 mm/vmalloc.c:2337
 __purge_vmap_area_lazy+0x77a/0xb00 mm/vmalloc.c:2427
 drain_vmap_area_work+0x27/0x40 mm/vmalloc.c:2461
 process_one_work+0x93a/0x15a0 kernel/workqueue.c:3279
 process_scheduled_works kernel/workqueue.c:3362 [inline]
 worker_thread+0x9b0/0xee0 kernel/workqueue.c:3443
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
rcu: rcu_preempt kthread starved for 10583 jiffies! g20973 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:27424 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5258 [inline]
 __schedule+0x150e/0x5070 kernel/sched/core.c:6866
 __schedule_loop kernel/sched/core.c:6948 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6963
 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+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: cc cc cc cc 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 33 9e 2a 00 f3 0f 1e fa fb f4 <e9> 48 ee 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90000197de0 EFLAGS: 000002c6
RAX: af4b269a8d1dda00 RBX: ffffffff819786ba RCX: af4b269a8d1dda00
RDX: 0000000000000001 RSI: ffffffff8d997e54 RDI: ffffffff8be07960
RBP: ffffc90000197f10 R08: ffff8880b87336db R09: 1ffff110170e66db
R10: dffffc0000000000 R11: ffffed10170e66dc R12: ffffffff8fa22f70
R13: 1ffff11003adab70 R14: 0000000000000001 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff888125d25000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f002dd72a60 CR3: 000000001f7d4000 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:767
 default_idle_call+0x73/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:191 [inline]
 do_idle+0x1ea/0x520 kernel/sched/idle.c:332
 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430
 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312
 common_startup_64+0x13e/0x147
 </TASK>