rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P21640/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=158749, q=40 ncpus=2)
task:syz.9.3356      state:R  running task     stack:25960 pid:21640 ppid:11767  flags:0x00004002
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:__sanitizer_cov_trace_pc+0x45/0x60 kernel/kcov.c:221
Code: ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 1c 16 00 00 00 74 2c 8b 91 f8 15 00 00 83 fa 02 75 21 48 8b 91 00 16 00 00 48 8b 32 <48> 8d 7e 01 8b 89 fc 15 00 00 48 39 cf 73 08 48 89 3a 48 89 44 f2
RSP: 0018:ffffc90002e677a0 EFLAGS: 00000246
RAX: ffffffff8415302b RBX: ffffffff84154fcf RCX: ffff88802b560000
RDX: ffffc9000be99000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: 0000000000000001 R08: dffffc0000000000 R09: 1ffffffff2237ea0
R10: dffffc0000000000 R11: fffffbfff2237ea1 R12: 0000000000000cc0
R13: 0000000000000001 R14: ffffea0001614680 R15: dffffc0000000000
 blkcg_css+0xb/0x1c0 block/blk-cgroup.c:104
 blk_cgroup_congested+0xbe/0x220 block/blk-cgroup.c:2191
 __folio_throttle_swaprate+0x71/0x1a0 mm/swapfile.c:3649
 folio_throttle_swaprate include/linux/swap.h:649 [inline]
 shmem_add_to_page_cache+0x9dd/0x1b30 mm/shmem.c:793
 shmem_get_folio_gfp+0xf08/0x2aa0 mm/shmem.c:2071
 shmem_get_folio mm/shmem.c:2164 [inline]
 shmem_write_begin+0xf2/0x420 mm/shmem.c:2706
 generic_perform_write+0x2fe/0x5c0 mm/filemap.c:4031
 shmem_file_write_iter+0xfb/0x120 mm/shmem.c:2883
 call_write_iter include/linux/fs.h:2018 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x46c/0x990 fs/read_write.c:584
 ksys_write+0x150/0x260 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f663cf5b78e
RSP: 002b:00007f663de49da8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f663de4a6c0 RCX: 00007f663cf5b78e
RDX: 00000000013bd7ef RSI: 00007f6632df7000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 00007f663de49ee0 R14: 00007f663de49ea0 R15: 00007f6632df7000
 </TASK>
rcu: rcu_preempt kthread starved for 10463 jiffies! g158749 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:27656 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5381 [inline]
 __schedule+0x1553/0x45a0 kernel/sched/core.c:6700
 schedule+0xbd/0x170 kernel/sched/core.c:6774
 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x313/0x1590 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866
 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>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 0 Comm: swapper/1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:pv_native_safe_halt+0xf/0x10 arch/x86/kernel/paravirt.c:148
Code: f8 22 02 c3 cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d 33 02 44 00 fb f4 <c3> 66 0f 1f 00 55 41 57 41 56 41 54 53 50 8b 2f eb 2e 41 89 de 80
RSP: 0018:ffffc90000187de0 EFLAGS: 000002c2
RAX: 6ee18adbe8a97c00 RBX: ffffffff8162a490 RCX: 6ee18adbe8a97c00
RDX: 0000000000000001 RSI: ffffffff8acac900 RDI: ffffffff8b1c81e0
RBP: ffffc90000187f20 R08: ffff8880b8f36b2b R09: 1ffff110171e6d65
R10: dffffc0000000000 R11: ffffed10171e6d66 R12: 1ffff1100384b780
R13: 1ffff92000030fc8 R14: 0000000000000001 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fae49432ea7 CR3: 000000002f00d000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:753
 default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97
 cpuidle_idle_call kernel/sched/idle.c:170 [inline]
 do_idle+0x1f0/0x4e0 kernel/sched/idle.c:282
 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:380
 start_secondary+0xee/0xf0 arch/x86/kernel/smpboot.c:323
 secondary_startup_64_no_verify+0x179/0x17b
 </TASK>