rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5543/1:b..l rcu: (detected by 1, t=10503 jiffies, g=12317, q=860 ncpus=2) task:syz-executor.5 state:R running task stack:20832 pid:5543 tgid:5543 ppid:5533 flags:0x00000002 Call Trace: context_switch kernel/sched/core.c:5188 [inline] __schedule+0x1800/0x4a60 kernel/sched/core.c:6529 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:6851 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x264/0x550 kernel/locking/lockdep.c:5763 Code: 2b 00 74 08 4c 89 f7 e8 0a 02 8b 00 f6 44 24 61 02 0f 85 85 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25 RSP: 0018:ffffc90002fdf040 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 1ffff920005fbe14 RCX: 34ada3afe232b500 RDX: dffffc0000000000 RSI: ffffffff8c0ae6e0 RDI: ffffffff8c606a80 RBP: ffffc90002fdf198 R08: ffffffff93731847 R09: 1ffffffff26e6308 R10: dffffc0000000000 R11: fffffbfff26e6309 R12: 1ffff920005fbe10 R13: dffffc0000000000 R14: ffffc90002fdf0a0 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:326 [inline] rcu_read_lock include/linux/rcupdate.h:838 [inline] page_ext_get+0x3d/0x2a0 mm/page_ext.c:535 __page_table_check_zero+0xb1/0x350 mm/page_table_check.c:148 page_table_check_alloc include/linux/page_table_check.h:33 [inline] post_alloc_hook+0x206/0x230 mm/page_alloc.c:1494 prep_new_page mm/page_alloc.c:1501 [inline] get_page_from_freelist+0x2e4c/0x2f10 mm/page_alloc.c:3442 __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4700 alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2263 pagetable_alloc_noprof include/linux/mm.h:2868 [inline] __pud_alloc_one_noprof include/asm-generic/pgalloc.h:174 [inline] pud_alloc_one_noprof include/asm-generic/pgalloc.h:195 [inline] __pud_alloc+0x93/0x4a0 mm/memory.c:6056 pud_alloc include/linux/mm.h:2825 [inline] copy_pud_range mm/memory.c:1269 [inline] copy_p4d_range mm/memory.c:1313 [inline] copy_page_range+0xb30/0xe90 mm/memory.c:1411 dup_mmap kernel/fork.c:749 [inline] dup_mm kernel/fork.c:1672 [inline] copy_mm+0x11ea/0x1f30 kernel/fork.c:1721 copy_process+0x187c/0x3e10 kernel/fork.c:2387 kernel_clone+0x226/0x8f0 kernel/fork.c:2800 __do_sys_clone kernel/fork.c:2943 [inline] __se_sys_clone kernel/fork.c:2927 [inline] __x64_sys_clone+0x258/0x2a0 kernel/fork.c:2927 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5bb187add3 RSP: 002b:00007fff7833d1c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f5bb187add3 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: 0000555586952750 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10550 jiffies! g12317 f0x0 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:26448 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5188 [inline] __schedule+0x1800/0x4a60 kernel/sched/core.c:6529 __schedule_loop kernel/sched/core.c:6606 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6621 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2581 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2034 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2236 kthread+0x2f2/0x390 kernel/kthread.c:389 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5823 Comm: syz-executor.4 Not tainted 6.11.0-rc3-syzkaller-00315-ge0fac5fc8b76 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 RIP: 0010:hlock_class kernel/locking/lockdep.c:227 [inline] RIP: 0010:__lock_acquire+0x129f/0x2040 kernel/locking/lockdep.c:5139 Code: 10 8b 18 81 e3 ff 1f 00 00 48 89 d8 48 c1 e8 06 48 8d 3c c5 40 18 73 93 be 08 00 00 00 e8 79 ed 8a 00 48 0f a3 1d 31 31 03 12 <73> 1d 48 69 c3 c8 00 00 00 48 8d 98 40 77 41 93 48 ba 00 00 00 00 RSP: 0018:ffffc900041179f0 EFLAGS: 00000057 RAX: 0000000000000001 RBX: 00000000000001b8 RCX: ffffffff816fe707 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff93731870 RBP: e4c0a9e1e38d5b9c R08: ffffffff93731877 R09: 1ffffffff26e630e R10: dffffc0000000000 R11: fffffbfff26e630f R12: 0000000000000001 R13: ffff88802216a8d8 R14: 1ffff1100442d520 R15: ffff88802216a900 FS: 00007f8d6971b6c0(0000) GS:ffff8880b9200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8d6971aec0 CR3: 000000002a2e6000 CR4: 0000000000350ef0 Call Trace: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759 __might_fault+0xc6/0x120 mm/memory.c:6388 rseq_get_rseq_cs kernel/rseq.c:161 [inline] rseq_ip_fixup kernel/rseq.c:281 [inline] __rseq_handle_notify_resume+0x120/0x14e0 kernel/rseq.c:329 rseq_handle_notify_resume include/linux/rseq.h:38 [inline] rseq_signal_deliver include/linux/rseq.h:47 [inline] setup_rt_frame arch/x86/kernel/signal.c:212 [inline] handle_signal arch/x86/kernel/signal.c:267 [inline] arch_do_signal_or_restart+0x3ab/0x860 arch/x86/kernel/signal.c:312 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0xc9/0x370 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f8d69720d40 Code: 41 28 48 85 ff 74 03 48 89 07 5d c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 f3 0f 1e fa 55 48 89 e5 41 57 41 56 41 55 41 54 <53> 48 83 ec 20 83 ff 0f 0f 87 f5 01 00 00 b8 01 00 00 00 89 f9 d3 RSP: 002b:00007f8d6971b0b0 EFLAGS: 00000202 RAX: 00007f8d69720d30 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 00007f8d68b1d600 RSI: 00007f8d6971b140 RDI: 0000000000000001 RBP: 00007f8d6971b0d0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f8d68babf80 R15: 00007ffcb4682818 sched: RT throttling activated