rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P6608/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=15533, q=1623 ncpus=2)
task:syz.1.131       state:R  running task     stack:25920 pid:6608  tgid:6606  ppid:5839   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_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_is_held_type+0x137/0x190 kernel/locking/lockdep.c:5945
Code: 01 75 44 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 75 4c 41 f7 c4 00 02 00 00 74 01 fb 65 48 8b 05 49 fa 22 07 <48> 3b 44 24 08 75 43 89 d8 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f
RSP: 0018:ffffc90002f07258 EFLAGS: 00000206
RAX: aada9d51bdda8f00 RBX: 0000000000000000 RCX: aada9d51bdda8f00
RDX: ffff88802abadb80 RSI: ffffffff8d97a89b RDI: ffffffff8bc08460
RBP: 00000000ffffffff R08: ffffffff8477a89d R09: ffffffff8df41b20
R10: dffffc0000000000 R11: fffff9400034c4f7 R12: 0000000000000246
R13: ffff88802abadb80 R14: ffffffff8df41be0 R15: 0000000000000002
 lock_is_held include/linux/lockdep.h:249 [inline]
 rcu_read_lock_sched_held+0x89/0x100 kernel/rcu/update.c:126
 task_css include/linux/cgroup.h:460 [inline]
 blkcg_css+0x71/0x1d0 block/blk-cgroup.c:110
 blk_cgroup_congested+0xbc/0x210 block/blk-cgroup.c:2238
 __folio_throttle_swaprate+0x3c/0x140 mm/swapfile.c:4034
 folio_throttle_swaprate include/linux/swap.h:608 [inline]
 shmem_add_to_page_cache+0x6f1/0xba0 mm/shmem.c:899
 shmem_alloc_and_add_folio+0x829/0xf40 mm/shmem.c:1958
 shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2556
 shmem_fault+0x179/0x390 mm/shmem.c:2757
 __do_fault+0x138/0x390 mm/memory.c:5320
 do_read_fault mm/memory.c:5755 [inline]
 do_fault mm/memory.c:5889 [inline]
 do_pte_missing+0x2206/0x3330 mm/memory.c:4401
 handle_pte_fault mm/memory.c:6273 [inline]
 __handle_mm_fault mm/memory.c:6411 [inline]
 handle_mm_fault+0x1b26/0x32b0 mm/memory.c:6580
 faultin_page mm/gup.c:1126 [inline]
 __get_user_pages+0x1650/0x29f0 mm/gup.c:1428
 populate_vma_page_range+0x29f/0x3a0 mm/gup.c:1860
 __mm_populate+0x24c/0x380 mm/gup.c:1963
 mm_populate include/linux/mm.h:3706 [inline]
 vm_mmap_pgoff+0x387/0x4d0 mm/util.c:586
 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: 0033:0x7fb35d58f749
RSP: 002b:00007fb35e511038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007fb35d7e5fa0 RCX: 00007fb35d58f749
RDX: b635773f06ebbee2 RSI: 0000000000b36000 RDI: 0000200000000000
RBP: 00007fb35d613f91 R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb35d7e6038 R14: 00007fb35d7e5fa0 R15: 00007ffe5b166f18
 </TASK>
rcu: rcu_preempt kthread starved for 10441 jiffies! g15533 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:27168 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:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 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 b3 70 0c 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:ffffffff8dc07d80 EFLAGS: 000002c6
RAX: d34a0f365761c400 RBX: ffffffff8197928a RCX: d34a0f365761c400
RDX: 0000000000000001 RSI: ffffffff8d793d57 RDI: ffffffff8bc08460
RBP: ffffffff8dc07ea8 R08: ffff8880b86336db R09: 1ffff110170c66db
R10: dffffc0000000000 R11: ffffed10170c66dc R12: ffffffff8f822c70
R13: 1ffffffff1b92a68 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888125e32000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f06849b9358 CR3: 0000000027f46000 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
 rest_init+0x2de/0x300 init/main.c:757
 start_kernel+0x3a7/0x400 init/main.c:1206
 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
 common_startup_64+0x13e/0x147
 </TASK>