rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (0 ticks this GP) idle=bef/1/0x4000000000000002 softirq=11330/11330 fqs=0 (detected by 1, t=10502 jiffies, g=15489, q=17319) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 5506 Comm: syz.1.112 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:debug_lockdep_rcu_enabled+0x0/0x30 kernel/rcu/update.c:279 Code: a8 cd 03 00 75 e8 48 c7 c7 20 26 2b 8a 48 c7 c6 a0 4a 2b 8a e8 f1 0a f5 ff 0f 0b eb d1 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 <31> c0 83 3d fb 75 cd 03 00 74 1d 83 3d 72 a8 cd 03 00 74 14 65 48 RSP: 0000:ffffc9000394ec48 EFLAGS: 00000093 RAX: ffffffff819bdc46 RBX: 0000000000000001 RCX: ffff888018bb8000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000394ed90 R08: ffffc9000394ed17 R09: ffffc9000394ed00 R10: dffffc0000000000 R11: fffff52000729da3 R12: 1ffff92000729d9c R13: ffffc9000394ede0 R14: dffffc0000000000 R15: ffff888074f0afc0 FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd201c20d90 CR3: 000000001e55d000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_read_unlock+0xb/0x90 include/linux/rcupdate.h:769 __perf_output_begin kernel/events/ring_buffer.c:262 [inline] perf_output_begin_forward+0x79b/0xa40 kernel/events/ring_buffer.c:271 __perf_event_output kernel/events/core.c:7804 [inline] perf_event_output_forward+0x19b/0x2e0 kernel/events/core.c:7822 __perf_event_overflow+0x364/0x530 kernel/events/core.c:9515 perf_swevent_overflow kernel/events/core.c:9591 [inline] perf_swevent_event+0x4ad/0x530 kernel/events/core.c:9629 perf_tp_event+0x383/0xbf0 kernel/events/core.c:10047 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021 perf_trace_preemptirq_template+0x2aa/0x360 include/trace/events/preemptirq.h:14 trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40 trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713 RIP: 0010:rcu_read_unlock_special+0x7f/0x4a0 kernel/rcu/tree_plugin.h:674 Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 12 f2 9c 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08 RSP: 0000:ffffc9000394f420 EFLAGS: 00000206 RAX: c5f62f80a3f50900 RBX: 1ffff92000729e88 RCX: c5f62f80a3f50900 RDX: dffffc0000000000 RSI: ffffffff8a2b2780 RDI: ffffffff8a79f980 RBP: ffffc9000394f4f0 R08: ffffffff901d40c7 R09: 1ffffffff203a818 R10: dffffc0000000000 R11: fffffbfff203a819 R12: ffffffff8c322f00 R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422 rcu_read_unlock include/linux/rcupdate.h:772 [inline] __unlock_page_memcg+0xea/0x100 mm/memcontrol.c:2093 zap_pte_range mm/memory.c:1384 [inline] zap_pmd_range mm/memory.c:1505 [inline] zap_pud_range mm/memory.c:1534 [inline] zap_p4d_range mm/memory.c:1555 [inline] unmap_page_range+0xf96/0x2500 mm/memory.c:1576 unmap_vmas+0x131/0x250 mm/memory.c:1653 exit_mmap+0x3b9/0x640 mm/mmap.c:3216 __mmput+0x115/0x3b0 kernel/fork.c:1127 exit_mm+0x588/0x6e0 kernel/exit.c:550 do_exit+0x5a9/0x20c0 kernel/exit.c:870 do_group_exit+0x12e/0x300 kernel/exit.c:997 get_signal+0x6ca/0x12c0 kernel/signal.c:2900 arch_do_signal_or_restart+0xe7/0x12c0 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fc1193b1ef9 Code: Unable to access opcode bytes at RIP 0x7fc1193b1ecf. RSP: 002b:00007fc118a150e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007fc11961cfa8 RCX: 00007fc1193b1ef9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fc11961cfa8 RBP: 00007fc11961cfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc11961d038 R14: 00007ffc906c2ae0 R15: 00007ffc906c2bc8 rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g15489 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=4727 rcu: rcu_preempt kthread starved for 10502 jiffies! g15489 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:26864 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117 rcu_gp_fqs_loop+0x2be/0x11d0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x9b/0x370 kernel/rcu/tree.c:2145 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 5506 Comm: syz.1.112 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x0/0x80 kernel/kcov.c:294 Code: 28 4d 39 ca 77 22 89 ff 89 f6 4a c7 44 02 08 03 00 00 00 4a 89 7c 02 10 4a 89 74 02 18 4a 89 44 02 20 48 ff c1 48 89 0a c3 90 <48> 8b 04 24 65 48 8b 0d 44 4b 89 7e 65 8b 15 45 4b 89 7e 81 e2 00 RSP: 0000:ffffc9000394ef20 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff888018bb8000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000005 R08: ffffffff8d89e36f R09: 1ffffffff1b13c6d R10: dffffc0000000000 R11: fffffbfff1b13c6e R12: 0000000000000001 R13: ffff88807be9d390 R14: ffff8880b9035120 R15: ffffc9000394f000 FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd201c20d90 CR3: 000000001e55d000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: perf_swevent_overflow kernel/events/core.c:9591 [inline] perf_swevent_event+0x4b8/0x530 kernel/events/core.c:9629 perf_tp_event+0x383/0xbf0 kernel/events/core.c:10047 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021 perf_trace_preemptirq_template+0x2aa/0x360 include/trace/events/preemptirq.h:14 trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40 trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713 RIP: 0010:rcu_read_unlock_special+0x7f/0x4a0 kernel/rcu/tree_plugin.h:674 Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 12 f2 9c 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08 RSP: 0000:ffffc9000394f420 EFLAGS: 00000206 RAX: c5f62f80a3f50900 RBX: 1ffff92000729e88 RCX: c5f62f80a3f50900 RDX: dffffc0000000000 RSI: ffffffff8a2b2780 RDI: ffffffff8a79f980 RBP: ffffc9000394f4f0 R08: ffffffff901d40c7 R09: 1ffffffff203a818 R10: dffffc0000000000 R11: fffffbfff203a819 R12: ffffffff8c322f00 R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422 rcu_read_unlock include/linux/rcupdate.h:772 [inline] __unlock_page_memcg+0xea/0x100 mm/memcontrol.c:2093 zap_pte_range mm/memory.c:1384 [inline] zap_pmd_range mm/memory.c:1505 [inline] zap_pud_range mm/memory.c:1534 [inline] zap_p4d_range mm/memory.c:1555 [inline] unmap_page_range+0xf96/0x2500 mm/memory.c:1576 unmap_vmas+0x131/0x250 mm/memory.c:1653 exit_mmap+0x3b9/0x640 mm/mmap.c:3216 __mmput+0x115/0x3b0 kernel/fork.c:1127 exit_mm+0x588/0x6e0 kernel/exit.c:550 do_exit+0x5a9/0x20c0 kernel/exit.c:870 do_group_exit+0x12e/0x300 kernel/exit.c:997 get_signal+0x6ca/0x12c0 kernel/signal.c:2900 arch_do_signal_or_restart+0xe7/0x12c0 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fc1193b1ef9 Code: Unable to access opcode bytes at RIP 0x7fc1193b1ecf. RSP: 002b:00007fc118a150e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007fc11961cfa8 RCX: 00007fc1193b1ef9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fc11961cfa8 RBP: 00007fc11961cfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc11961d038 R14: 00007ffc906c2ae0 R15: 00007ffc906c2bc8