rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P14338/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=63889, q=201 ncpus=2)
task:syz.4.2299      state:R  running task     stack:24776 pid:14338 tgid:14337 ppid:5807   task_flags:0x400740 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x1139/0x6150 kernel/sched/core.c:6863
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7190
 irqentry_exit+0x1d8/0x8c0 kernel/entry/common.c:216
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_is_held_type+0x10c/0x150 kernel/locking/lockdep.c:5945
Code: ff ff 65 0f c1 05 5c f0 3a 08 83 f8 01 75 2d 9c 58 f6 c4 02 75 43 48 f7 04 24 00 02 00 00 74 01 fb 48 83 c4 08 44 89 e8 5b 5d <41> 5c 41 5d 41 5e 41 5f e9 87 2c 03 00 45 31 ed eb b5 90 0f 0b 90
RSP: 0018:ffffc9000214e9f0 EFLAGS: 00000292
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff8daa7ab3 RDI: ffffffff8bf2b300
RBP: ffff888025be8000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: ffff888025be8b30 R12: ffff888025be8000
R13: 0000000000000000 R14: 00000000ffffffff R15: 0000000000000003
 lock_is_held include/linux/lockdep.h:249 [inline]
 rcu_read_lock_sched_held kernel/rcu/update.c:126 [inline]
 rcu_read_lock_sched_held+0x3e/0x70 kernel/rcu/update.c:120
 task_css include/linux/cgroup.h:460 [inline]
 blkcg_css.part.0+0x8b/0x1d0 block/blk-cgroup.c:110
 blkcg_css block/blk-cgroup.c:2241 [inline]
 blk_cgroup_congested+0xf8/0x270 block/blk-cgroup.c:2238
 __folio_throttle_swaprate+0x3d/0x190 mm/swapfile.c:4034
 folio_throttle_swaprate include/linux/swap.h:608 [inline]
 shmem_add_to_page_cache+0x5b6/0xa70 mm/shmem.c:899
 shmem_alloc_and_add_folio+0x662/0xc20 mm/shmem.c:1958
 shmem_get_folio_gfp+0x67f/0x1610 mm/shmem.c:2556
 shmem_get_folio mm/shmem.c:2662 [inline]
 shmem_write_begin+0x1a4/0x3b0 mm/shmem.c:3315
 generic_perform_write+0x3c4/0x900 mm/filemap.c:4314
 shmem_file_write_iter+0x10e/0x140 mm/shmem.c:3490
 __kernel_write_iter+0x31a/0xb10 fs/read_write.c:619
 dump_emit_page fs/coredump.c:1298 [inline]
 dump_user_range+0x413/0xb70 fs/coredump.c:1372
 elf_core_dump+0x29c3/0x3c10 fs/binfmt_elf.c:2111
 coredump_write fs/coredump.c:1049 [inline]
 do_coredump fs/coredump.c:1126 [inline]
 vfs_coredump+0x2b85/0x55e0 fs/coredump.c:1200
 get_signal+0x22e1/0x26d0 kernel/signal.c:3019
 arch_do_signal_or_restart+0x8f/0x7e0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
 exit_to_user_mode_loop+0x8c/0x540 kernel/entry/common.c:75
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
 do_syscall_64+0x4ee/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbdb218f749
RSP: 002b:00007fbdb2f89038 EFLAGS: 00000246 ORIG_RAX: 00000000000000c8
RAX: 0000000000000000 RBX: 00007fbdb23e5fa0 RCX: 00007fbdb218f749
RDX: 0000000000000000 RSI: 0000000000000008 RDI: 00000000000006c3
RBP: 00007fbdb2213f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbdb23e6038 R14: 00007fbdb23e5fa0 R15: 00007ffd552692f8
 </TASK>
rcu: rcu_preempt kthread starved for 10563 jiffies! g63889 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:28320 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x1139/0x6150 kernel/sched/core.c:6863
 __schedule_loop kernel/sched/core.c:6945 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6960
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x983/0xb10 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 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82
Code: c6 5f 02 c3 cc cc cc cc 0f 1f 00 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 13 59 12 00 fb f4 <e9> cc 35 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffc90000197de8 EFLAGS: 000002c6
RAX: 00000000034d9e31 RBX: 0000000000000001 RCX: ffffffff8b7806d9
RDX: 0000000000000000 RSI: ffffffff8dacdb2d RDI: ffffffff8bf2b300
RBP: ffffed1003b56498 R08: 0000000000000001 R09: ffffed10170a673d
R10: ffff8880b85339eb R11: ffff88801dab2ff0 R12: 0000000000000001
R13: ffff88801dab24c0 R14: ffffffff9088aed0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8881249f6000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000240 CR3: 0000000049096000 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+0x6c/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:191 [inline]
 do_idle+0x38d/0x510 kernel/sched/idle.c:332
 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430
 start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312
 common_startup_64+0x13e/0x148
 </TASK>