rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P8144/1:b..l rcu: (detected by 1, t=10503 jiffies, g=28817, q=314 ncpus=2) task:syz-executor state:R running task stack:20544 pid:8144 tgid:8144 ppid:1 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5371 [inline] __schedule+0x18f6/0x4cd0 kernel/sched/core.c:6758 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:7080 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:__nr_to_section include/linux/mmzone.h:1905 [inline] RIP: 0010:__pfn_to_section include/linux/mmzone.h:2013 [inline] RIP: 0010:lookup_page_ext mm/page_ext.c:251 [inline] RIP: 0010:page_ext_get+0x138/0x2a0 mm/page_ext.c:526 Code: 44 9a e8 6b 79 f4 ff 48 8b 05 b4 09 13 18 48 85 c0 74 41 4c 89 e1 48 c1 e9 16 48 8d 1c c8 48 89 d8 48 c1 e8 03 42 80 3c 38 00 <74> 08 48 89 df e8 3e 79 f4 ff 48 8b 1b 48 85 db 74 1f 4c 89 e5 48 RSP: 0018:ffffc90005aa77f8 EFLAGS: 00000246 RAX: 1ffff11047ffdea8 RBX: ffff88823ffef540 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000001710a80 RDI: 000000ffffffffc0 RBP: 000000ffffffffc0 R08: ffffffff82310f9e R09: 1ffffffff285b708 R10: dffffc0000000000 R11: fffffbfff285b709 R12: 000000000005c42a R13: 0000000000000000 R14: ffffffff82310ed0 R15: dffffc0000000000 __page_table_check_zero+0xb1/0x350 mm/page_table_check.c:148 page_table_check_free include/linux/page_table_check.h:41 [inline] free_pages_prepare mm/page_alloc.c:1128 [inline] free_frozen_pages+0xe21/0x10e0 mm/page_alloc.c:2660 vfree+0x1c3/0x360 mm/vmalloc.c:3383 kcov_put kernel/kcov.c:439 [inline] kcov_close+0x28/0x50 kernel/kcov.c:535 __fput+0x3e9/0x9f0 fs/file_table.c:450 task_work_run+0x24f/0x310 kernel/task_work.c:227 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0xa2a/0x28e0 kernel/exit.c:938 do_group_exit+0x207/0x2c0 kernel/exit.c:1087 get_signal+0x16b2/0x1750 kernel/signal.c:3017 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0xce/0x340 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc7d678473c RSP: 002b:00007fff81e99650 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: fffffffffffffe00 RBX: 0000000000000003 RCX: 00007fc7d678473c RDX: 0000000000000030 RSI: 00007fff81e99700 RDI: 00000000000000f9 RBP: 00007fff81e996ac R08: 0000000000000000 R09: 0079746972756365 R10: 00007fc7d69487e0 R11: 0000000000000246 R12: 0000000000000054 R13: 0000000000030716 R14: 00007fff81e99700 R15: 0000000000000012 rcu: rcu_preempt kthread starved for 10178 jiffies! g28817 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:25336 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5371 [inline] __schedule+0x18f6/0x4cd0 kernel/sched/core.c:6758 __schedule_loop kernel/sched/core.c:6835 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6850 schedule_timeout+0x15a/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2024 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2226 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 24 Comm: ksoftirqd/1 Not tainted 6.13.0-rc6-next-20250107-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:__kasan_check_read+0x6/0x20 mm/kasan/shadow.c:31 Code: 78 01 ff 31 db eb d0 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 89 f6 <48> 8b 0c 24 31 d2 e9 af e6 ff ff 66 2e 0f 1f 84 00 00 00 00 00 0f RSP: 0018:ffffc900001e7678 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffff88801d2f8000 RDX: 0000000000000100 RSI: 0000000000000008 RDI: ffffffff901ac9f0 RBP: ffffc900001e77b0 R08: ffffffff89becd72 R09: 1ffffffff203593e R10: dffffc0000000000 R11: fffffbfff203593f R12: 1ffff9200003cedc R13: ffffffff89beca3b R14: dffffc0000000000 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005571d376e950 CR3: 000000006304a000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: instrument_atomic_read include/linux/instrumented.h:68 [inline] _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] cpumask_test_cpu include/linux/cpumask.h:570 [inline] cpu_online include/linux/cpumask.h:1116 [inline] trace_lock_release include/trace/events/lock.h:69 [inline] lock_release+0xb0/0xa30 kernel/locking/lockdep.c:5862 rcu_lock_release include/linux/rcupdate.h:347 [inline] rcu_read_unlock include/linux/rcupdate.h:880 [inline] process_backlog+0x6ed/0x15b0 net/core/dev.c:6120 __napi_poll+0xcb/0x490 net/core/dev.c:6885 napi_poll net/core/dev.c:6954 [inline] net_rx_action+0x89b/0x1240 net/core/dev.c:7076 handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561 run_ksoftirqd+0xca/0x130 kernel/softirq.c:950 smpboot_thread_fn+0x544/0xa30 kernel/smpboot.c:164 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244