rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=9634/1/0x4000000000000000 softirq=43284/43286 fqs=1 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P8867/1:b..l rcu: (detected by 1, t=10502 jiffies, g=45113, q=499 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 8861 Comm: syz.3.487 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:_find_first_zero_bit+0x8/0xb0 lib/find_bit.c:148 Code: 86 e8 0c bb 7f fd e9 7c ff ff ff 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 <41> 55 41 54 53 48 85 f6 74 46 48 89 f3 49 89 fe 49 bc 00 00 00 00 RSP: 0018:ffffc9000406fc30 EFLAGS: 00000046 RAX: 0000000000000000 RBX: ffff88803493e150 RCX: 0000000080000001 RDX: dffffc0000000000 RSI: 0000000000000002 RDI: ffff88803493e150 RBP: 0000000080000000 R08: 1ffff11006927ad9 R09: 0000000000000000 R10: ffff88803493d80c R11: fffff5200080df78 R12: 1ffffffff1c4d9d7 R13: 0000000080000000 R14: 0000000000000002 R15: ffff88803493d5c0 FS: 00007f02eb0386c0(0000) GS:ffff888125287000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f69019b3368 CR3: 000000004207b000 CR4: 0000000000350ef0 Call Trace: find_first_zero_bit include/linux/find.h:391 [inline] __mm_get_cid kernel/sched/sched.h:3865 [inline] mm_get_cid kernel/sched/sched.h:3880 [inline] sched_mm_cid_fork+0x67c/0x10e0 kernel/sched/core.c:10954 bprm_execve+0xdb7/0x1510 fs/exec.c:1771 do_execveat_common+0x50d/0x690 fs/exec.c:1846 __do_sys_execveat fs/exec.c:1941 [inline] __se_sys_execveat fs/exec.c:1934 [inline] __x64_sys_execveat+0xc7/0xf0 fs/exec.c:1934 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0x560 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f02ea19ce59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f02eb038028 EFLAGS: 00000246 ORIG_RAX: 0000000000000142 RAX: ffffffffffffffda RBX: 00007f02ea415fa0 RCX: 00007f02ea19ce59 RDX: 0000000000000000 RSI: 0000200000000000 RDI: 000000000000000a RBP: 00007f02ea232d6f R08: 0000000000001000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f02ea416038 R14: 00007f02ea415fa0 R15: 00007ffe19962588 task:dhcpcd-run-hook state:R running task stack:27232 pid:8867 tgid:8867 ppid:8850 task_flags:0x40004c flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 kernel/sched/core.c:7189 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7513 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x760 kernel/entry/common.c:164 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:rcu_is_watching+0x67/0xb0 kernel/rcu/tree.c:753 Code: 89 f7 e8 5c 2c 86 00 48 c7 c3 d8 c9 3a 93 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38 84 c0 75 34 8b 03 65 ff 0d a9 c1 8e 11 <74> 11 83 e0 04 c1 e8 02 5b 41 5e 41 5f e9 72 72 65 ff cc e8 01 bd RSP: 0018:ffffc9000402f340 EFLAGS: 00000286 RAX: 0000000000349634 RBX: ffff8880b86339d8 RCX: 0000000080000001 RDX: 00000000ae0c93a7 RSI: ffffffff8c28b840 RDI: ffffffff8c28b800 RBP: 0000000000000000 R08: ffffffff81af520d R09: ffffffff8e95cce0 R10: dffffc0000000000 R11: ffffffff81b0e040 R12: ffff8880773d0000 R13: ffff8880549d2b00 R14: ffffffff8e26c790 R15: dffffc0000000000 rcu_read_unlock include/linux/rcupdate.h:867 [inline] class_rcu_destructor include/linux/rcupdate.h:1181 [inline] is_module_text_address+0x147/0x1e0 kernel/module/main.c:3923 kernel_text_address+0x94/0xe0 kernel/extable.c:119 __kernel_text_address+0xd/0x30 kernel/extable.c:79 unwind_get_return_address+0x4d/0x90 arch/x86/kernel/unwind_orc.c:385 arch_stack_walk+0xfb/0x150 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x31c/0x660 mm/slub.c:5420 kmalloc_noprof include/linux/slab.h:950 [inline] slab_free_hook mm/slub.c:2641 [inline] slab_free mm/slub.c:6251 [inline] kmem_cache_free+0x156/0x650 mm/slub.c:6378 anon_vma_free mm/rmap.c:137 [inline] __put_anon_vma+0x12b/0x2d0 mm/rmap.c:2915 put_anon_vma mm/internal.h:216 [inline] unlink_anon_vmas+0x58b/0x730 mm/rmap.c:536 free_pgtables+0x836/0xb70 mm/memory.c:414 exit_mmap+0x490/0x9e0 mm/mmap.c:1312 __mmput+0x118/0x430 kernel/fork.c:1178 exit_mm+0x1f6/0x2d0 kernel/exit.c:582 do_exit+0x6a2/0x22c0 kernel/exit.c:964 do_group_exit+0x21b/0x2d0 kernel/exit.c:1119 __do_sys_exit_group kernel/exit.c:1130 [inline] __se_sys_exit_group kernel/exit.c:1128 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1128 x64_sys_call+0x221a/0x2240 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0x560 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f69017e36c5 RSP: 002b:00007fffa711a238 EFLAGS: 00000202 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007fffa711a504 RCX: 00007f69017e36c5 RDX: 00000000000000e7 RSI: ffffffffffffff88 RDI: 0000000000000000 RBP: 0000000000000003 R08: 00007fffa711a330 R09: 0000000000000002 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007fffa711a570 R14: 00007f69019f3000 R15: 0000560c216f2d98 rcu: rcu_preempt kthread starved for 10500 jiffies! g45113 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:27640 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0x164/0x360 kernel/sched/core.c:7283 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297 kthread+0x389/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 8870 Comm: syz.9.486 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xfd4/0x13d0 kernel/smp.c:892 Code: 89 ee 83 e6 01 31 ff e8 9a 07 0c 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 45 03 0c 00 eb 37 f3 90 43 0f b6 04 2c <84> c0 75 10 41 f7 06 01 00 00 00 74 1e e8 2a 03 0c 00 eb e5 44 89 RSP: 0018:ffffc9000502fa20 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff8880b873c148 RCX: ffff888028ee1ec0 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000502fb60 R08: ffffffff9030dbf7 R09: 1ffffffff2061b7e R10: dffffc0000000000 R11: fffffbfff2061b7f R12: 1ffff110170c8589 R13: dffffc0000000000 R14: ffff8880b8642c48 R15: 0000000000000000 FS: 00007ff1f1bf66c0(0000) GS:ffff888125387000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff1f1bf5ff8 CR3: 000000003410b000 CR4: 0000000000350ef0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1057 on_each_cpu include/linux/smp.h:72 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2773 [inline] smp_text_poke_batch_finish+0x5f5/0x1160 arch/x86/kernel/alternative.c:2983 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_slow_inc_cpuslocked+0x80/0xf0 kernel/jump_label.c:168 static_key_slow_inc+0x1a/0x30 kernel/jump_label.c:191 io_uring_create+0xed/0x9a0 io_uring/io_uring.c:2998 io_uring_setup io_uring/io_uring.c:3125 [inline] __do_sys_io_uring_setup io_uring/io_uring.c:3159 [inline] __se_sys_io_uring_setup+0x2a8/0x2c0 io_uring/io_uring.c:3150 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0x560 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff1f399ce59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ff1f1bf6028 EFLAGS: 00000246 ORIG_RAX: 00000000000001a9 RAX: ffffffffffffffda RBX: 00007ff1f3c16180 RCX: 00007ff1f399ce59 RDX: 0000000000000000 RSI: 0000200000000040 RDI: 0000000000000007 RBP: 00007ff1f3a32d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ff1f3c16218 R14: 00007ff1f3c16180 R15: 00007ffff2745bf8