rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (0 ticks this GP) idle=71d/1/0x4000000000000002 softirq=16529/16529 fqs=0 (detected by 1, t=10502 jiffies, g=21253, q=1371) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 7453 Comm: syz.3.3000 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 RIP: 0010:memset_erms+0x9/0x10 arch/x86/lib/memset_64.S:64 Code: c1 e9 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 aa 4c 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 RSP: 0018:ffffc9000c78f278 EFLAGS: 00010002 RAX: ffffffff8198a300 RBX: dffffc0000000000 RCX: 0000000000000080 RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffffc9000c78f380 RBP: ffffc9000c78f4e8 R08: ffffc9000c78f3ff R09: ffffc9000c78f300 R10: dffffc0000000000 R11: fffff520018f1e80 R12: ffffe8ffffc35488 R13: 1ffff920018f1e58 R14: ffffe8ffffc7e000 R15: ffffc9000c78f300 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7accd79feb CR3: 000000000ce8e000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: perf_tp_event+0xfa/0xbe0 kernel/events/core.c:10040 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10031 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 82 fc 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: 0018:ffffc9000c78f720 EFLAGS: 00000206 RAX: d0a7771bb0272f00 RBX: 1ffff920018f1ee8 RCX: d0a7771bb0272f00 RDX: dffffc0000000000 RSI: ffffffff8a2b2b60 RDI: ffffffff8a7a4b40 RBP: ffffc9000c78f7f0 R08: ffffffff910150c7 R09: 1ffffffff2202a18 R10: dffffc0000000000 R11: fffffbfff2202a19 R12: ffffffff8d123400 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+0xee4/0x2410 mm/memory.c:1576 unmap_vmas+0x131/0x250 mm/memory.c:1653 exit_mmap+0x3b9/0x640 mm/mmap.c:3216 __mmput+0x115/0x390 kernel/fork.c:1133 exit_mm+0x632/0x7b0 kernel/exit.c:557 do_exit+0x5b8/0x2110 kernel/exit.c:877 do_group_exit+0x12c/0x2f0 kernel/exit.c:1004 __do_sys_exit_group kernel/exit.c:1015 [inline] __se_sys_exit_group kernel/exit.c:1013 [inline] __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1013 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f673d18f559 Code: Unable to access opcode bytes at RIP 0x7f673d18f52f. RSP: 002b:00007ffe901776f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f673d18f559 RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007ffe9017775c R08: 0000000000000000 R09: 00000000000927c0 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000251 R13: 00000000000927c0 R14: 000000000002ff10 R15: 00007ffe901777b0 rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g21253 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=10852 rcu: rcu_preempt kthread starved for 10502 jiffies! g21253 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:27840 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11c3/0x4350 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/0x11f0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x9a/0x370 kernel/rcu/tree.c:2145 kthread+0x42e/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: 7453 Comm: syz.3.3000 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 RIP: 0010:check_kcov_mode kernel/kcov.c:182 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x32/0x60 kernel/kcov.c:205 Code: 54 4c 89 7e 65 8b 15 55 4c 89 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 34 16 00 00 00 74 2c 8b 91 10 16 00 00 <83> fa 02 75 21 48 8b 91 18 16 00 00 48 8b 32 48 8d 7e 01 8b 89 14 RSP: 0018:ffffc9000c78eff8 EFLAGS: 00000046 RAX: ffffffff81980568 RBX: ffffffff817f50b8 RCX: ffff88807bf88000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc9000c78f0f0 R08: ffffc9000c78f177 R09: ffffc9000c78f140 R10: dffffc0000000000 R11: fffff520018f1e2f R12: dffffc0000000000 R13: ffffc9000c78f1a6 R14: 0000000000010101 R15: ffffc9000c78f300 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7accd79feb CR3: 000000000ce8e000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: perf_prepare_sample+0x418/0x1cb0 kernel/events/core.c:7650 __perf_event_output kernel/events/core.c:7812 [inline] perf_event_output_forward+0x185/0x2e0 kernel/events/core.c:7832 __perf_event_overflow+0x35f/0x550 kernel/events/core.c:9525 perf_tp_event+0x324/0xbe0 kernel/events/core.c:10057 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10031 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 82 fc 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: 0018:ffffc9000c78f720 EFLAGS: 00000206 RAX: d0a7771bb0272f00 RBX: 1ffff920018f1ee8 RCX: d0a7771bb0272f00 RDX: dffffc0000000000 RSI: ffffffff8a2b2b60 RDI: ffffffff8a7a4b40 RBP: ffffc9000c78f7f0 R08: ffffffff910150c7 R09: 1ffffffff2202a18 R10: dffffc0000000000 R11: fffffbfff2202a19 R12: ffffffff8d123400 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+0xee4/0x2410 mm/memory.c:1576 unmap_vmas+0x131/0x250 mm/memory.c:1653 exit_mmap+0x3b9/0x640 mm/mmap.c:3216 __mmput+0x115/0x390 kernel/fork.c:1133 exit_mm+0x632/0x7b0 kernel/exit.c:557 do_exit+0x5b8/0x2110 kernel/exit.c:877 do_group_exit+0x12c/0x2f0 kernel/exit.c:1004 __do_sys_exit_group kernel/exit.c:1015 [inline] __se_sys_exit_group kernel/exit.c:1013 [inline] __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1013 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f673d18f559 Code: Unable to access opcode bytes at RIP 0x7f673d18f52f. RSP: 002b:00007ffe901776f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f673d18f559 RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007ffe9017775c R08: 0000000000000000 R09: 00000000000927c0 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000251 R13: 00000000000927c0 R14: 000000000002ff10 R15: 00007ffe901777b0