rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P31028/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=198677, q=392 ncpus=2)
task:syz.5.5973      state:R  running task     stack:26248 pid:31028 tgid:31023 ppid:30405  task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5290 [inline]
 __schedule+0x14db/0x5030 kernel/sched/core.c:6902
 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7229
 irqentry_exit+0x5e3/0x670 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+0x107/0x150 kernel/locking/lockdep.c:5945
Code: 18 00 00 b8 ff ff ff ff 65 0f c1 05 a3 10 44 07 83 f8 01 75 25 9c 58 a9 00 02 00 00 75 39 41 f7 c4 00 02 00 00 74 01 fb 89 d8 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 90 0f 0b 90 48 c7
RSP: 0018:ffffc9000b79f690 EFLAGS: 00000206
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000046
RDX: ffff88801cb41e40 RSI: ffffffff8db8bddd RDI: ffffffff8be09760
RBP: 00000000ffffffff R08: ffffffff8478e83d R09: ffffffff8e144ce0
R10: dffffc0000000000 R11: fffff9400022486f R12: 0000000000000246
R13: ffff88801cb41e40 R14: ffffffff8e17e898 R15: 0000000000000004
 lock_is_held include/linux/lockdep.h:249 [inline]
 task_css include/linux/cgroup.h:460 [inline]
 blkcg_css+0xcc/0x1d0 block/blk-cgroup.c:110
 blk_cgroup_congested+0xbc/0x210 block/blk-cgroup.c:2238
 __folio_throttle_swaprate+0x3c/0x140 mm/swapfile.c:3926
 folio_throttle_swaprate include/linux/swap.h:587 [inline]
 shmem_add_to_page_cache+0x6f1/0xba0 mm/shmem.c:900
 shmem_alloc_and_add_folio+0x829/0xf40 mm/shmem.c:1971
 shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2540
 shmem_get_folio mm/shmem.c:2646 [inline]
 shmem_write_begin+0x16c/0x330 mm/shmem.c:3299
 generic_perform_write+0x2c5/0x900 mm/filemap.c:4314
 shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3474
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x5c9/0xb30 fs/read_write.c:688
 ksys_write+0x145/0x250 fs/read_write.c:740
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5a1eb8f749
RSP: 002b:00007f5a1facb038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f5a1ede6090 RCX: 00007f5a1eb8f749
RDX: 00000000fffffd9d RSI: 0000200000000100 RDI: 0000000000000004
RBP: 00007f5a1ec13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5a1ede6128 R14: 00007f5a1ede6090 R15: 00007ffc0e0ab298
 </TASK>
rcu: rcu_preempt kthread starved for 1327 jiffies! g198677 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:27680 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5290 [inline]
 __schedule+0x14db/0x5030 kernel/sched/core.c:6902
 __schedule_loop kernel/sched/core.c:6984 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6999
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x11b0 kernel/rcu/tree.c:2095
 rcu_gp_kthread+0x9b/0x2d0 kernel/rcu/tree.c:2297
 kthread+0x389/0x480 kernel/kthread.c:467
 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </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+0x13/0x20 arch/x86/kernel/paravirt.c:63
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 e3 bd 29 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90000197e20 EFLAGS: 00000242
RAX: 000000000354e737 RBX: ffffffff8197831e RCX: 0000000080000001
RDX: 0000000000000001 RSI: ffffffff8d9a73db RDI: ffffffff8be09760
RBP: ffffc90000197f10 R08: ffff8880b873375b R09: 1ffff110170e66eb
R10: dffffc0000000000 R11: ffffed10170e66ec R12: ffffffff8fa2d9f0
R13: 1ffff11003adab58 R14: 0000000000000001 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff888125cf9000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001000 CR3: 0000000084f44000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 000000000000bd32
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/kernel/process.c:766 [inline]
 default_idle+0x9/0x20 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+0x1be/0x4d0 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>