rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: (detected by 0, t=10502 jiffies, g=9761, q=301 ncpus=2)
rcu: All QSes seen, last rcu_preempt kthread activity 10500 (4294956491-4294945991), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10500 jiffies! g9761 f0x2 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:27784 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5257 [inline]
__schedule+0x14bc/0x5000 kernel/sched/core.c:6864
__schedule_loop kernel/sched/core.c:6946 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6961
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
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 5842 Comm: iou-sqp-5840 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__sanitizer_cov_trace_pc+0x5d/0x70 kernel/kcov.c:235
Code: 48 16 00 00 83 fa 02 75 21 48 8b 91 50 16 00 00 48 8b 32 48 8d 7e 01 8b 89 4c 16 00 00 48 39 cf 73 08 48 89 3a 48 89 44 f2 08 4e 99 9a 09 cc 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90
RSP: 0018:ffffc900040bfa78 EFLAGS: 00000293
RAX: ffffffff84863af5 RBX: ffff8880313ef898 RCX: ffff888032a15b80
RDX: 0000000000000000 RSI: 0000000000063d9e RDI: 0000000000000000
RBP: ffffc900040bfe30 R08: ffffffff8f813377 R09: 1ffffffff1f0266e
R10: dffffc0000000000 R11: fffffbfff1f0266f R12: dffffc0000000000
R13: 0000000000000000 R14: 00000000ffffd5ca R15: 0000000100061368
FS: 000055556824f380(0000) GS:ffff888125e4f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000002040 CR3: 0000000072526000 CR4: 00000000003526f0
Call Trace:
io_sq_thread+0x1235/0x2020 io_uring/sqpoll.c:362
ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246