rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (0 ticks this GP) idle=e21/1/0x4000000000000000 softirq=14435/14435 fqs=0 (detected by 1, t=10506 jiffies, g=16413, q=336) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 6681 Comm: syz.0.676 Not tainted 5.15.189-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:mark_usage kernel/locking/lockdep.c:4512 [inline] RIP: 0010:__lock_acquire+0xd4a/0x7c60 kernel/locking/lockdep.c:4966 Code: 60 00 00 83 3b 00 74 22 4c 89 ef 4c 89 fe ba 06 00 00 00 e8 38 a4 00 00 49 b8 00 00 00 00 00 fc ff df 85 c0 0f 84 a5 4c 00 00 <4c> 89 ef 4c 89 fe ba 08 00 00 00 e8 16 a4 00 00 85 c0 0f 84 7b 4c RSP: 0018:ffffc900034ced20 EFLAGS: 00000046 RAX: 0000000000000002 RBX: 0000000000000002 RCX: 0000000000000002 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8ffb70c0 RBP: ffffc900034cef70 R08: dffffc0000000000 R09: fffffbfff1ff6e19 R10: fffffbfff1ff6e19 R11: 1ffffffff1ff6e18 R12: ffff8880263346e0 R13: ffff888026333b80 R14: ffffffff8f93fff8 R15: ffff8880263346c0 FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b32223ffc CR3: 00000000651a0000 CR4: 00000000003506f0 DR0: 0000200000000300 DR1: 0000200000000300 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:312 rcu_read_lock include/linux/rcupdate.h:739 [inline] BPF_PROG_RUN_ARRAY include/linux/bpf.h:1333 [inline] trace_call_bpf+0xf3/0x5a0 kernel/trace/bpf_trace.c:127 perf_trace_run_bpf_submit+0x79/0x1c0 kernel/events/core.c:10002 perf_trace_preemptirq_template+0x2be/0x380 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+0x84/0x480 kernel/rcu/tree_plugin.h:671 Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 7d 16 9e 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b RSP: 0018:ffffc900034cf420 EFLAGS: 00000206 RAX: 9e2e3a19a5144d00 RBX: 1ffff92000699e88 RCX: 9e2e3a19a5144d00 RDX: dffffc0000000000 RSI: ffffffff8a0b15c0 RDI: ffffffff8a599340 RBP: ffffc900034cf4f0 R08: dffffc0000000000 R09: fffffbfff1ff6e19 R10: fffffbfff1ff6e19 R11: 1ffffffff1ff6e18 R12: ffffffff8c120800 R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422 rcu_read_unlock include/linux/rcupdate.h:771 [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+0xfbc/0x2520 mm/memory.c:1576 unmap_vmas+0x11b/0x230 mm/memory.c:1653 exit_mmap+0x38f/0x5f0 mm/mmap.c:3212 __mmput+0x115/0x3b0 kernel/fork.c:1127 exit_mm+0x567/0x6c0 kernel/exit.c:550 do_exit+0x5a1/0x20a0 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+0xc1/0x1300 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+0xb1/0x140 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: 0033:0x7f3e52121be9 Code: Unable to access opcode bytes at RIP 0x7f3e52121bbf. RSP: 002b:00007f3e503890e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f3e52348fa8 RCX: 00007f3e52121be9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f3e52348fa8 RBP: 00007f3e52348fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f3e52349038 R14: 00007ffe2d158150 R15: 00007ffe2d158238 rcu: rcu_preempt kthread timer wakeup didn't happen for 10505 jiffies! g16413 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=9684 rcu: rcu_preempt kthread starved for 10506 jiffies! g16413 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:27848 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5030 [inline] __schedule+0x11b8/0x43b0 kernel/sched/core.c:6376 schedule+0x11b/0x1e0 kernel/sched/core.c:6459 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914 rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x98/0x350 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: 6681 Comm: syz.0.676 Not tainted 5.15.189-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:__lock_acquire+0x1051/0x7c60 kernel/locking/lockdep.c:5007 Code: 41 01 d6 29 da 41 89 dc 41 c1 c4 04 41 31 d4 48 c7 c0 48 a2 69 8d 48 c1 e8 03 42 0f b6 04 00 84 c0 0f 85 8c 5a 00 00 41 01 de <83> 3d 40 97 0d 0c 00 4c 8b 7c 24 18 0f 85 f9 02 00 00 48 83 7c 24 RSP: 0018:ffffc900034ced20 EFLAGS: 00000083 RAX: 0000000000000000 RBX: 00000000cb74e569 RCX: 00000000219023bc RDX: 0000000083a0bcab RSI: 000000000d5ce631 RDI: ffffffff8ffb70c0 RBP: ffffc900034cef70 R08: dffffc0000000000 R09: fffffbfff1ff6e19 R10: fffffbfff1ff6e19 R11: 1ffffffff1ff6e18 R12: 0000000034eeea37 R13: ffff888026333b80 R14: 00000000b36544d9 R15: 00000000bb1a50e2 FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b32223ffc CR3: 00000000651a0000 CR4: 00000000003506f0 DR0: 0000200000000300 DR1: 0000200000000300 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:312 rcu_read_lock include/linux/rcupdate.h:739 [inline] BPF_PROG_RUN_ARRAY include/linux/bpf.h:1333 [inline] trace_call_bpf+0xf3/0x5a0 kernel/trace/bpf_trace.c:127 perf_trace_run_bpf_submit+0x79/0x1c0 kernel/events/core.c:10002 perf_trace_preemptirq_template+0x2be/0x380 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+0x84/0x480 kernel/rcu/tree_plugin.h:671 Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 7d 16 9e 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b RSP: 0018:ffffc900034cf420 EFLAGS: 00000206 RAX: 9e2e3a19a5144d00 RBX: 1ffff92000699e88 RCX: 9e2e3a19a5144d00 RDX: dffffc0000000000 RSI: ffffffff8a0b15c0 RDI: ffffffff8a599340 RBP: ffffc900034cf4f0 R08: dffffc0000000000 R09: fffffbfff1ff6e19 R10: fffffbfff1ff6e19 R11: 1ffffffff1ff6e18 R12: ffffffff8c120800 R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422 rcu_read_unlock include/linux/rcupdate.h:771 [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+0xfbc/0x2520 mm/memory.c:1576 unmap_vmas+0x11b/0x230 mm/memory.c:1653 exit_mmap+0x38f/0x5f0 mm/mmap.c:3212 __mmput+0x115/0x3b0 kernel/fork.c:1127 exit_mm+0x567/0x6c0 kernel/exit.c:550 do_exit+0x5a1/0x20a0 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+0xc1/0x1300 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+0xb1/0x140 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: 0033:0x7f3e52121be9 Code: Unable to access opcode bytes at RIP 0x7f3e52121bbf. RSP: 002b:00007f3e503890e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f3e52348fa8 RCX: 00007f3e52121be9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f3e52348fa8 RBP: 00007f3e52348fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f3e52349038 R14: 00007ffe2d158150 R15: 00007ffe2d158238