rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P25377/1:b..l P25338/1:b..l rcu: (detected by 1, t=10502 jiffies, g=150177, q=224 ncpus=2) task:syz.7.4904 state:R running task stack:24304 pid:25338 tgid:25337 ppid:17869 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x14bc/0x5000 kernel/sched/core.c:6863 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7190 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x16c/0x340 kernel/locking/lockdep.c:5872 Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 f4 39 e0 10 <48> 3b 44 24 58 0f 85 e5 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc9000b687420 EFLAGS: 00000206 RAX: 6ced4c52264ab600 RBX: 0000000000000000 RCX: 6ced4c52264ab600 RDX: 00000000ba12b26f RSI: ffffffff8d978ed0 RDI: ffffffff8bc08360 RBP: ffffffff8264496c R08: ffffffff8264496c R09: ffffffff8df419e0 R10: dffffc0000000000 R11: ffffed100a401279 R12: 0000000000000002 R13: ffffffff8df419e0 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:867 [inline] class_rcu_constructor include/linux/rcupdate.h:1195 [inline] kernfs_root+0x38/0x230 fs/kernfs/kernfs-internal.h:75 kernfs_root_is_locked fs/kernfs/kernfs-internal.h:109 [inline] kernfs_parent+0x51/0x190 fs/kernfs/kernfs-internal.h:133 kernfs_unlink_sibling+0x5a/0x180 fs/kernfs/dir.c:423 __kernfs_remove+0x3d4/0x650 fs/kernfs/dir.c:1517 kernfs_remove_by_name_ns+0xaf/0x130 fs/kernfs/dir.c:1720 kernfs_remove_by_name include/linux/kernfs.h:633 [inline] remove_files fs/sysfs/group.c:28 [inline] sysfs_remove_group+0xfc/0x2f0 fs/sysfs/group.c:328 sysfs_remove_groups+0x54/0xb0 fs/sysfs/group.c:352 destroy_gid_attrs drivers/infiniband/core/sysfs.c:1182 [inline] ib_free_port_attrs+0xc5/0x3b0 drivers/infiniband/core/sysfs.c:1407 remove_one_compat_dev drivers/infiniband/core/device.c:1038 [inline] rdma_dev_exit_net+0x1d8/0x340 drivers/infiniband/core/device.c:1176 ops_exit_list net/core/net_namespace.c:199 [inline] ops_undo_list+0x49a/0x990 net/core/net_namespace.c:252 setup_net+0x2e8/0x330 net/core/net_namespace.c:462 copy_net_ns+0x3e3/0x570 net/core/net_namespace.c:581 create_new_namespaces+0x3e7/0x6a0 kernel/nsproxy.c:130 copy_namespaces+0x438/0x4b0 kernel/nsproxy.c:195 copy_process+0x1689/0x3950 kernel/fork.c:2224 kernel_clone+0x21e/0x820 kernel/fork.c:2651 __do_sys_clone kernel/fork.c:2792 [inline] __se_sys_clone kernel/fork.c:2776 [inline] __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2776 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f52c658f749 RSP: 002b:00007f52c745afe8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007f52c67e5fa0 RCX: 00007f52c658f749 RDX: 0000200000001f80 RSI: 0000200000001f40 RDI: 0000000044208000 RBP: 00007f52c6613f91 R08: 0000200000002000 R09: 0000200000002000 R10: 0000200000001fc0 R11: 0000000000000206 R12: 0000000000000000 R13: 00007f52c67e6038 R14: 00007f52c67e5fa0 R15: 00007ffecbbc2798 task:syz.0.4920 state:R running task stack:25336 pid:25377 tgid:25375 ppid:16295 task_flags:0x400040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x14bc/0x5000 kernel/sched/core.c:6863 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7190 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:mtree_range_walk+0x36f/0x840 lib/maple_tree.c:-1 Code: eb 23 e8 84 c5 6c f6 c7 44 24 04 00 00 00 00 31 db eb 60 e8 73 c5 6c f6 48 89 d9 48 bd 00 00 00 00 00 fc ff df 48 8b 44 24 48 24 e8 5a c5 6c f6 8b 44 24 04 89 c3 4c 8b 6c 24 18 48 bd 00 00 RSP: 0000:ffffc9000d427c40 EFLAGS: 00000283 RAX: ffff88807db20008 RBX: 0000000000000001 RCX: 0000000000000001 RDX: ffffc9001a99a000 RSI: 000000000004e793 RDI: 000000000004e794 RBP: dffffc0000000000 R08: ffff88801bfa1e80 R09: 0000000000000003 R10: 0000000000000003 R11: 0000000000000002 R12: ffff88807db20010 R13: 00007fc807dfffff R14: 00007fc7fe509000 R15: ffff88807db20000 mas_state_walk lib/maple_tree.c:3298 [inline] mas_walk+0xc6/0x2e0 lib/maple_tree.c:4599 lock_vma_under_rcu+0x193/0x4a0 mm/mmap_lock.c:253 do_user_addr_fault+0x2d9/0x1380 arch/x86/mm/fault.c:1327 handle_page_fault arch/x86/mm/fault.c:1476 [inline] exc_page_fault+0x82/0x100 arch/x86/mm/fault.c:1532 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7fc807e509e6 RSP: 002b:00007fc808d5a4a0 EFLAGS: 00010206 RAX: 0000000000909001 RBX: 00007fc808d5a540 RCX: 0000000000000062 RDX: 0000000000000005 RSI: 0000000000000001 RDI: 00007fc808d5a5e0 RBP: 0000000000000102 R08: 00007fc7fdc00000 R09: 0000000000909000 R10: 0000000000000000 R11: 00007fc808d5a550 R12: 0000000000000001 R13: 00007fc80802fc40 R14: 0000000000000000 R15: 00007fc808d5a5e0 rcu: rcu_preempt kthread starved for 10578 jiffies! g150177 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R running task stack:26832 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x14bc/0x5000 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0x165/0x360 kernel/sched/core.c:6960 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 25364 Comm: syz.1.4912 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:fpregs_activate+0x15/0x1c0 arch/x86/kernel/fpu/context.h:49 Code: 6c ff ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57 41 56 53 48 89 fb e8 52 f7 57 00 48 c7 c7 60 a2 65 8b c6 15 f2 09 65 48 89 1d 4e 2b 15 11 0f 1f 44 00 00 e8 34 f7 57 RSP: 0018:ffffc9000b3d7a90 EFLAGS: 00000246 RAX: ffffffff8169b9ae RBX: ffff8880695719c0 RCX: 0000000000080000 RDX: ffffc90015401000 RSI: 000000000007ffff RDI: ffffffff8b65a260 RBP: 0000000000000000 R08: ffff888069570007 R09: 1ffff1100d2ae000 R10: dffffc0000000000 R11: ffffed100d2ae001 R12: ffffffff8169f16b R13: dffffc0000000000 R14: ffff8880695719c0 R15: dffffc0000000000 FS: 00007f79e11b36c0(0000) GS:ffff888125e35000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc8081e7dac CR3: 000000001c2bc000 CR4: 0000000000350ef0 Call Trace: fpregs_mark_activate+0x64/0xe0 arch/x86/kernel/fpu/core.c:903 restore_fpregs_from_user arch/x86/kernel/fpu/signal.c:317 [inline] __fpu_restore_sig arch/x86/kernel/fpu/signal.c:346 [inline] fpu__restore_sig+0x95b/0x10d0 arch/x86/kernel/fpu/signal.c:480 restore_sigcontext arch/x86/kernel/signal_64.c:95 [inline] __ia32_sys_rt_sigreturn+0x704/0x860 arch/x86/kernel/signal_64.c:268 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f79e038f747 Code: ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 RSP: 002b:00007f79e11b3038 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 00007f79e05e6090 RCX: 00007f79e038f749 RDX: 0000000000000008 RSI: 0000200000000240 RDI: 0000000000000007 RBP: 00007f79e0413f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f79e05e6128 R14: 00007f79e05e6090 R15: 00007ffd03a34968 raw-gadget.0 gadget.1: ignoring, device is not running