rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P6471/1:b..l
	(detected by 0, t=10502 jiffies, g=24749, q=402 ncpus=2)
task:syz.4.576       state:R  running task     stack:22760 pid:6471  ppid:4257   flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x143f/0x4570 kernel/sched/core.c:6561
 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6873
 irqentry_exit+0x53/0x80 kernel/entry/common.c:439
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:blk_cgroup_congested+0xe1/0x220 block/blk-cgroup.c:2004
Code: ff ff 48 85 c0 0f 84 9f 00 00 00 48 89 c5 49 bf 00 00 00 00 00 fc ff df 41 bc b8 09 00 00 48 89 e8 48 c1 e8 03 42 80 3c 38 00 <74> 08 48 89 ef e8 b5 d4 b1 fd 48 8b 5d 00 4c 01 e3 48 89 df be 04
RSP: 0018:ffffc90004ddf638 EFLAGS: 00000246
RAX: 1ffffffff2eb95e8 RBX: 0000000000000000 RCX: 0000000000080000
RDX: ffffc9000e2c2000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffffff975caf40 R08: ffffffff8430370a R09: ffffed100a60b938
R10: 0000000000000000 R11: dffffc0000000001 R12: 00000000000009b8
R13: ffffc90004ddf778 R14: ffffffff84303609 R15: dffffc0000000000
 __cgroup_throttle_swaprate+0x6d/0x1b0 mm/swapfile.c:3671
 cgroup_throttle_swaprate include/linux/swap.h:662 [inline]
 folio_throttle_swaprate include/linux/swap.h:671 [inline]
 shmem_add_to_page_cache+0xb90/0x1e60 mm/shmem.c:717
 shmem_get_folio_gfp+0x164e/0x3470 mm/shmem.c:1971
 shmem_get_folio mm/shmem.c:2072 [inline]
 shmem_write_begin+0x16e/0x4e0 mm/shmem.c:2556
 generic_perform_write+0x2fc/0x5e0 mm/filemap.c:3845
 __generic_file_write_iter+0x176/0x400 mm/filemap.c:3973
 generic_file_write_iter+0xab/0x310 mm/filemap.c:4005
 call_write_iter include/linux/fs.h:2265 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x857/0xbc0 fs/read_write.c:584
 ksys_write+0x19c/0x2c0 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fd9f278bc1f
RSP: 002b:00007fd9f3581df0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00000000013bd7ef RCX: 00007fd9f278bc1f
RDX: 00000000013bd7ef RSI: 00007fd9e7ff7000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000005580
R10: 00002000000079c2 R11: 0000000000000293 R12: 0000000000000003
R13: 00007fd9f3581ef0 R14: 00007fd9f3581eb0 R15: 00007fd9e7ff7000
 </TASK>
rcu: rcu_preempt kthread starved for 10476 jiffies! g24749 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:26712 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x143f/0x4570 kernel/sched/core.c:6561
 schedule+0xbf/0x180 kernel/sched/core.c:6637
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1965
 rcu_gp_fqs_loop+0x2d2/0x1150 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0xa3/0x3b0 kernel/rcu/tree.c:1905
 kthread+0x28d/0x320 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:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 6479 Comm: syz.1.580 Not tainted 6.1.132-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:fpu__restore_sig+0x25b/0x1300 arch/x86/kernel/fpu/signal.c:500
Code: 09 89 c3 31 ff 89 c6 e8 93 a6 57 00 85 db 74 67 e8 2a a3 57 00 48 8b 7c 24 38 e8 50 c5 ff ff 31 c0 48 c7 44 24 60 0e 36 e0 45 <48> b9 00 00 00 00 00 fc ff df 48 8b 54 24 58 c7 04 11 00 00 00 00
RSP: 0018:ffffc90004567aa0 EFLAGS: 00000246
RAX: d0634b5e1579de01 RBX: 0000000000000000 RCX: ffffffff973c2103
RDX: dffffc0000000000 RSI: ffffffff8b0c1dc0 RDI: ffffffff8b5f70e0
RBP: ffffc90004567c50 R08: ffffffff815c0116 R09: ffffed100318b581
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffff1100601de16
FS:  00005555893e5500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2ce20e CR3: 0000000057459000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 restore_sigcontext+0x633/0x700 arch/x86/kernel/signal.c:140
 __do_sys_rt_sigreturn+0x190/0x250 arch/x86/kernel/signal.c:675
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f85dfd8d169
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fffd50b1748 EFLAGS: 00000246
RAX: ffffffffffffff92 RBX: 000000000002a2f5 RCX: 00007f85dfd8d169
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f85dffa5fac
RBP: 0000000000000032 R08: 0000000000000010 R09: 00000009d50b1a3f
R10: 00007fffd50b1840 R11: 0000000000000246 R12: 00007f85dffa5fac
R13: 00007fffd50b1840 R14: 000000000002a327 R15: 00007fffd50b1860
 </TASK>