syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P6164/1:b..l
	(detected by 0, t=10502 jiffies, g=25973, q=189 ncpus=2)
task:syz.1.373       state:R  running task     stack:23168 pid:6164  ppid:4266   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873
 irqentry_exit+0x63/0x70 kernel/entry/common.c:439
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:unwind_next_frame+0x0/0x20b0 arch/x86/kernel/unwind_orc.c:423
Code: 02 31 c0 5b 41 5e 41 5f c3 89 d9 80 e1 07 80 c1 03 38 c1 7c 97 48 89 df e8 5d 8d 98 00 eb 8d 66 2e 0f 1f 84 00 00 00 00 00 90 <55> 41 57 41 56 41 55 41 54 53 48 81 ec a0 00 00 00 48 89 fb 49 be
RSP: 0018:ffffc900051e6e40 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffffc900051e6f00 RCX: 0000000080000000
RDX: dffffc0000000000 RSI: ffffffff81c58f0b RDI: ffffc900051e6e48
RBP: ffffc900051e6ed0 R08: ffffc900051e6f10 R09: 0000000000000001
R10: fffff52000a3cdd5 R11: 1ffff92000a3cdd3 R12: ffff88802588bb80
R13: 1ffff92000a3cdf4 R14: ffffffff816fb740 R15: ffffc900051e6e48
 arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x98/0xe0 kernel/stacktrace.c:122
 save_stack+0xf3/0x1e0 mm/page_owner.c:127
 __reset_page_owner+0x51/0x1a0 mm/page_owner.c:148
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1459 [inline]
 free_pcp_prepare mm/page_alloc.c:1509 [inline]
 free_unref_page_prepare+0x8b4/0x9a0 mm/page_alloc.c:3384
 free_unref_page_list+0xbb/0x8e0 mm/page_alloc.c:3525
 release_pages+0x1f92/0x2200 mm/swap.c:1035
 __pagevec_release+0x6d/0xe0 mm/swap.c:1055
 pagevec_release include/linux/pagevec.h:71 [inline]
 folio_batch_release include/linux/pagevec.h:135 [inline]
 shmem_undo_range+0x75b/0x2050 mm/shmem.c:946
 shmem_truncate_range mm/shmem.c:1062 [inline]
 shmem_evict_inode+0x248/0xa40 mm/shmem.c:1171
 evict+0x485/0x870 fs/inode.c:705
 __dentry_kill+0x431/0x650 fs/dcache.c:611
 dentry_kill+0xb8/0x290 fs/dcache.c:-1
 dput+0xfa/0x1d0 fs/dcache.c:918
 __fput+0x5e0/0x920 fs/file_table.c:328
 task_work_run+0x1ca/0x250 kernel/task_work.c:203
 exit_task_work include/linux/task_work.h:39 [inline]
 do_exit+0x93e/0x2400 kernel/exit.c:880
 do_group_exit+0x217/0x2d0 kernel/exit.c:1022
 get_signal+0x1272/0x1350 kernel/signal.c:2871
 arch_do_signal_or_restart+0xb0/0x1230 arch/x86/kernel/signal.c:871
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 irqentry_exit_to_user_mode+0x5/0x30 kernel/entry/common.c:316
 exc_page_fault+0x88/0x100 arch/x86/mm/fault.c:1490
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608
RIP: 0033:0x7f794b78ebb1
RSP: 002b:fffffffffffffe70 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007f794b9d5fa0 RCX: 00007f794b78eba9
RDX: 0000000000000000 RSI: fffffffffffffe70 RDI: 0000000000008000
RBP: 00007f794b811e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f794b9d6038 R14: 00007f794b9d5fa0 R15: 00007ffeaabdbde8
 </TASK>
rcu: rcu_preempt kthread starved for 10545 jiffies! g25973 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
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:27840 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1965
 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 6375 Comm: syz.2.434 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202
Code: f5 ff 0f 1f 00 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 3e 18 42 f7 48 89 df e8 96 dd 42 f7 e8 61 d1 65 f7 fb bf 01 00 00 00 <e8> e6 5a 36 f7 65 8b 05 e7 13 e1 75 85 c0 74 02 5b c3 e8 34 25 df
RSP: 0018:ffffc900061afcf0 EFLAGS: 00000286
RAX: c9a89411936ad600 RBX: ffff8880689a1bc0 RCX: c9a89411936ad600
RDX: dffffc0000000000 RSI: ffffffff8a8c0500 RDI: 0000000000000001
RBP: ffffc900061aff10 R08: dffffc0000000000 R09: ffffed100d134379
R10: ffffed100d134379 R11: 1ffff1100d134378 R12: ffff888061f49dc0
R13: 1ffff92000c35ffe R14: 1ffff92000c35fa8 R15: ffffc900061afff0
FS:  0000555587694500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c3f64cf CR3: 000000006406c000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __ia32_sys_rt_sigreturn+0x184/0x790 arch/x86/kernel/signal.c:673
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f132892ada9
Code: 64 c7 00 16 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 90 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 c7 c0 0f 00 00 00 0f 05 <0f> 1f 80 00 00 00 00 48 81 ec 48 01 00 00 49 89 d0 64 48 8b 04 25
RSP: 002b:00007ffcf894b580 EFLAGS: 00000246 ORIG_RAX: 000000000000000f
RAX: ffffffffffffffda RBX: 000000000003cee1 RCX: 00007f132892ada9
RDX: 00007ffcf894b580 RSI: 00007ffcf894b6b0 RDI: 0000000000000011
RBP: 0000000000000032 R08: 00214135c1ca8572 R09: 0000001ef894be2f
R10: 00007ffcf894bc30 R11: 0000000000000246 R12: 00007f1328bd5fac
R13: 00007ffcf894bc30 R14: 000000000003cf13 R15: 00007ffcf894bc50
 </TASK>