sched: RT throttling activated rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 0, t=10502 jiffies, g=40025, q=244 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 10422 (4294976906-4294966484), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10423 jiffies! g40025 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:27840 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561 schedule+0xb9/0x180 kernel/sched/core.c:6637 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1965 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706 rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 PID: 8992 Comm: syz.2.1795 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:lock_acquire+0x20f/0x490 kernel/locking/lockdep.c:5666 Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f5 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 66 43 c7 44 3d 09 00 00 43 c6 44 3d 0b RSP: 0018:ffffc90004057a60 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0abd9a27935c4b00 RDX: 0000000000000000 RSI: ffffffff8a8c1680 RDI: ffffffff8adefd20 RBP: ffffc90004057b80 R08: dffffc0000000000 R09: fffffbfff215c44f R10: fffffbfff215c44f R11: 1ffffffff215c44e R12: 0000000000000000 R13: 1ffff9200080af58 R14: 0000000000000246 R15: dffffc0000000000 FS: 00007fec22e336c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000020000006b000 CR3: 00000000798ba000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __might_fault+0xc2/0x120 mm/memory.c:5852 _copy_from_user+0x27/0x170 lib/usercopy.c:14 copy_from_user include/linux/uaccess.h:161 [inline] restore_altstack+0x9a/0x4a0 kernel/signal.c:4257 __ia32_sys_rt_sigreturn+0x660/0x790 arch/x86/kernel/signal.c:678 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fec21f8eec7 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:00007fec22e33038 EFLAGS: 00000246 RAX: 0000000000000113 RBX: 00007fec221e5fa0 RCX: 00007fec21f8eec9 RDX: 0000000000000006 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 00007fec22011f91 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fec221e6038 R14: 00007fec221e5fa0 R15: 00007ffe11c46268