rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P6909/1:b..l
rcu: 	(detected by 1, t=10503 jiffies, g=16873, q=879 ncpus=2)
task:sed             state:R  running task     stack:24232 pid:6909  ppid:6908   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:692
RIP: 0010:lock_release+0x57c/0x8b0 kernel/locking/lockdep.c:5778
Code: 00 00 00 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 75 75 f7 44 24 50 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 2f 00 00 00 00 66 43 c7 44 2f 09 00 00 43 c6 44 2f 0b 00
RSP: 0000:ffffc900039b7d20 EFLAGS: 00000206
RAX: 0000000000000001 RBX: ffffffffffffffff RCX: d56b090f8b3dda00
RDX: 00000000ffffffff RSI: ffffffff8aaace20 RDI: ffffffff8afc71c0
RBP: ffffc900039b7e28 R08: dffffc0000000000 R09: 1ffffffff21b4ca0
R10: dffffc0000000000 R11: fffffbfff21b4ca1 R12: ffff88802b648ae0
R13: dffffc0000000000 R14: ffff88802b648ad0 R15: 1ffff92000736fb0
 up_read+0x16/0x20 kernel/locking/rwsem.c:1615
 vma_end_read+0xdd/0x170 include/linux/mm.h:693
 do_user_addr_fault+0xafe/0x12e0 arch/x86/mm/fault.c:1326
 handle_page_fault arch/x86/mm/fault.c:1465 [inline]
 exc_page_fault+0x67/0x110 arch/x86/mm/fault.c:1521
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:608
RIP: 0033:0x7fcccd2a7000
RSP: 002b:00007ffc2247bb48 EFLAGS: 00010206
RAX: 00007fcccd2a7000 RBX: 00007fcccd3106b0 RCX: 00007ffc2247bbf0
RDX: 00007ffc2247bbf0 RSI: 00007ffc2247bbc8 RDI: 0000000000000004
RBP: 0000000000000004 R08: 00007fcccd642af8 R09: 0000000000000000
R10: 00007ffc2247b7f0 R11: 0000000000000246 R12: 00007ffc2247bbc8
R13: 00007ffc2247bbf0 R14: 00007fcccd645310 R15: 0000000000000000
 </TASK>
rcu: rcu_preempt kthread starved for 10529 jiffies! g16873 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:27752 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 schedule+0xbd/0x170 kernel/sched/core.c:6773
 schedule_timeout+0x160/0x280 kernel/time/timer.c:2167
 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x99/0x380 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:
CPU: 1 PID: 6914 Comm: syz.2.19 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:202
Code: 00 f3 0f 1e fa 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 0a 90 ef f6 48 89 df e8 22 62 f0 f6 e8 6d 08 14 f7 fb bf 01 00 00 00 <e8> 32 79 e3 f6 65 8b 05 43 c5 8b 75 85 c0 74 02 5b c3 e8 60 a9 88
RSP: 0018:ffffc9000438fc98 EFLAGS: 00000282
RAX: 55f86fdc7546cb00 RBX: ffff88802b1965c0 RCX: 55f86fdc7546cb00
RDX: dffffc0000000000 RSI: ffffffff8aaabca0 RDI: 0000000000000001
RBP: ffff88802b196a58 R08: ffffffff8e4a7fef R09: 1ffffffff1c94ffd
R10: dffffc0000000000 R11: fffffbfff1c94ffe R12: 1ffff11005632d4b
R13: 0000000000000021 R14: dffffc0000000000 R15: 0000000000000000
FS:  00007f4a065eb6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000006b000 CR3: 000000002379f000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 spin_unlock_irq include/linux/spinlock.h:401 [inline]
 get_signal+0x11f5/0x1400 kernel/signal.c:2905
 arch_do_signal_or_restart+0x96/0x780 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xf6/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f4a0578eba7
Code: ff ff 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
RSP: 002b:00007f4a065eb0e8 EFLAGS: 00000246
RAX: 00000000000000ca RBX: 00007f4a059d5fa8 RCX: 00007f4a0578eba9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f4a059d5fa8
RBP: 00007f4a059d5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4a059d6038 R14: 00007ffc95390ea0 R15: 00007ffc95390f88
 </TASK>