rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P7168/1:b..l P5875/1:b..l P6499/1:b..l P6759/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=21461, q=5056 ncpus=2)
task:syz-executor    state:R  running task     stack:20920 pid:6759  tgid:6759  ppid:1      task_flags:0x40054c flags:0x00080003
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5282 [inline]
 __schedule+0x14db/0x5030 kernel/sched/core.c:6894
 preempt_schedule_notrace+0x57/0x90 kernel/sched/core.c:7171
 preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13
 rcu_is_watching+0x7f/0xb0 kernel/rcu/tree.c:753
 rcu_read_lock_held_common kernel/rcu/update.c:109 [inline]
 rcu_read_lock_held+0x15/0x50 kernel/rcu/update.c:349
 lookup_page_ext mm/page_ext.c:258 [inline]
 page_ext_lookup+0xe7/0x180 mm/page_ext.c:513
 page_ext_iter_begin include/linux/page_ext.h:132 [inline]
 __page_table_check_zero+0x135/0x3e0 mm/page_table_check.c:139
 page_table_check_free include/linux/page_table_check.h:43 [inline]
 free_pages_prepare mm/page_alloc.c:1437 [inline]
 __free_frozen_pages+0xbad/0xd10 mm/page_alloc.c:2976
 vfree+0x25a/0x400 mm/vmalloc.c:3471
 kcov_put kernel/kcov.c:442 [inline]
 kcov_close+0x28/0x50 kernel/kcov.c:543
 __fput+0x44c/0xa70 fs/file_table.c:468
 task_work_run+0x1d4/0x260 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x88c/0x2590 kernel/exit.c:971
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1112
 get_signal+0x1285/0x1340 kernel/signal.c:3034
 arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
 exit_to_user_mode_loop+0x87/0x4e0 kernel/entry/common.c:75
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
 do_syscall_64+0x2c1/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1bded915dc
RSP: 002b:00007ffe585f0520 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: 0000000000000040 RBX: 00007f1bdfb14620 RCX: 00007f1bded915dc
RDX: 0000000000000040 RSI: 00007f1bdfb14670 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007ffe585f0574 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f1bdfb14670 R15: 0000000000000000
 </TASK>
task:kworker/u8:68   state:R  running task     stack:24288 pid:6499  tgid:6499  ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: ib-unreg-wq ib_unregister_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5282 [inline]
 __schedule+0x14db/0x5030 kernel/sched/core.c:6894
 preempt_schedule_notrace+0x57/0x90 kernel/sched/core.c:7171
 preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13
 rcu_is_watching+0x7f/0xb0 kernel/rcu/tree.c:753
 rcu_read_lock include/linux/rcupdate.h:851 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1193 [inline]
 kernfs_root+0x55/0x230 fs/kernfs/kernfs-internal.h:75
 kernfs_next_descendant_post+0x83/0x310 fs/kernfs/dir.c:1378
 __kernfs_remove+0x1f0/0x660 fs/kernfs/dir.c:1495
 kernfs_remove_by_name_ns+0xaf/0x130 fs/kernfs/dir.c:1722
 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:1142 [inline]
 ib_free_port_attrs+0xc5/0x3b0 drivers/infiniband/core/sysfs.c:1367
 remove_one_compat_dev drivers/infiniband/core/device.c:1011 [inline]
 remove_compat_devs drivers/infiniband/core/device.c:1023 [inline]
 disable_device+0x230/0x320 drivers/infiniband/core/device.c:1305
 __ib_unregister_device+0x2cb/0x3f0 drivers/infiniband/core/device.c:1553
 ib_unregister_work+0x6d/0xe0 drivers/infiniband/core/device.c:1668
 process_one_work+0x93a/0x15a0 kernel/workqueue.c:3279
 process_scheduled_works kernel/workqueue.c:3362 [inline]
 worker_thread+0x9b0/0xee0 kernel/workqueue.c:3443
 kthread+0x389/0x480 kernel/kthread.c:467
 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
task:udevd           state:R  running task     stack:23544 pid:5875  tgid:5875  ppid:5193   task_flags:0x400140 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5282 [inline]
 __schedule+0x14db/0x5030 kernel/sched/core.c:6894
 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7221
 irqentry_exit+0x5e3/0x670 kernel/entry/common.c:216
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x222/0x340 kernel/locking/lockdep.c:5872
Code: ff ff ff e8 00 c6 c0 09 f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 1a 34 04 11 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 ff a3 c3 09 cc 48 8d 3d d7 c3 07
RSP: 0018:ffffc90004256f98 EFLAGS: 00000282
RAX: ca3c83d0e9fa7000 RBX: 0000000000000000 RCX: 0000000000000046
RDX: 00000000faf43aee RSI: ffffffff8db8dbf6 RDI: ffffffff8be09d60
RBP: ffffffff81745df5 R08: ffffffff81745df5 R09: ffffffff8e144f60
R10: ffffc90004257158 R11: fffff5200084ae2d R12: 0000000000000002
R13: ffffffff8e144f60 R14: 0000000000000000 R15: 0000000000000246
 rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 rcu_read_lock include/linux/rcupdate.h:850 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1193 [inline]
 unwind_next_frame+0xc2/0x23d0 arch/x86/kernel/unwind_orc.c:495
 __unwind_start+0x5b9/0x760 arch/x86/kernel/unwind_orc.c:773
 unwind_start arch/x86/include/asm/unwind.h:64 [inline]
 arch_stack_walk+0xe4/0x150 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0x9c/0xe0 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]
 __do_kmalloc_node mm/slub.c:5677 [inline]
 __kmalloc_noprof+0x41d/0x800 mm/slub.c:5689
 kmalloc_noprof include/linux/slab.h:962 [inline]
 tomoyo_realpath_from_path+0xe3/0x5d0 security/tomoyo/realpath.c:251
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_number_perm+0x1e8/0x5a0 security/tomoyo/file.c:728
 tomoyo_path_mknod+0x142/0x190 security/tomoyo/tomoyo.c:252
 security_path_mknod+0x17e/0x3a0 security/security.c:1391
 may_o_create+0x2d/0x370 fs/namei.c:4296
 lookup_open fs/namei.c:4437 [inline]
 open_last_lookups fs/namei.c:4581 [inline]
 path_openat+0x102e/0x3840 fs/namei.c:4825
 do_file_open+0x203/0x440 fs/namei.c:4857
 do_sys_openat2+0x105/0x1e0 fs/open.c:1366
 do_sys_open fs/open.c:1372 [inline]
 __do_sys_openat fs/open.c:1388 [inline]
 __se_sys_openat fs/open.c:1383 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1383
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd9004a7407
RSP: 002b:00007ffc76808910 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fd900c42880 RCX: 00007fd9004a7407
RDX: 0000000000080241 RSI: 00007ffc76808e70 RDI: ffffffffffffff9c
RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000000001b6 R11: 0000000000000202 R12: 0000560437aeddfc
R13: 0000560437aeddfc R14: 0000000000000001 R15: 00005604505ede00
 </TASK>
task:syz.3.286       state:R  running task     stack:25336 pid:7168  tgid:7168  ppid:5823   task_flags:0x40004c flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5282 [inline]
 __schedule+0x14db/0x5030 kernel/sched/core.c:6894
 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7221
 irqentry_exit+0x5e3/0x670 kernel/entry/common.c:216
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x222/0x340 kernel/locking/lockdep.c:5872
Code: ff ff ff e8 00 c6 c0 09 f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 1a 34 04 11 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 ff a3 c3 09 cc 48 8d 3d d7 c3 07
RSP: 0018:ffffc90003da7418 EFLAGS: 00000286
RAX: 33015f6ba185c600 RBX: 0000000000000000 RCX: 0000000000000046
RDX: 0000000010f0e9a2 RSI: ffffffff8db8dbf6 RDI: ffffffff8be09d60
RBP: ffffffff81745df5 R08: ffffffff81745df5 R09: ffffffff8e144f60
R10: ffffc90003da7578 R11: ffffffff81ad18d0 R12: 0000000000000002
R13: ffffffff8e144f60 R14: 0000000000000000 R15: 0000000000000246
 rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 rcu_read_lock include/linux/rcupdate.h:850 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1193 [inline]
 unwind_next_frame+0xc2/0x23d0 arch/x86/kernel/unwind_orc.c:495
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2556 [inline]
 slab_free mm/slub.c:6690 [inline]
 kmem_cache_free+0x197/0x620 mm/slub.c:6801
 anon_vma_chain_free mm/rmap.c:147 [inline]
 unlink_anon_vmas+0x368/0x730 mm/rmap.c:505
 free_pgtables+0x737/0x9d0 mm/memory.c:414
 exit_mmap+0x431/0xb10 mm/mmap.c:1288
 __mmput+0x118/0x430 kernel/fork.c:1177
 exit_mm+0x169/0x230 kernel/exit.c:581
 do_exit+0x81f/0x2590 kernel/exit.c:959
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1112
 __do_sys_exit_group kernel/exit.c:1123 [inline]
 __se_sys_exit_group kernel/exit.c:1121 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1121
 x64_sys_call+0x2210/0x2210 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa1f438f749
RSP: 002b:00007ffd4847f228 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fa1f438f749
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffd4847f28c R08: 0000000c4847f31f R09: 0000000000000036
R10: 0000000000000001 R11: 0000000000000246 R12: 000000000000003f
R13: 0000000000000036 R14: 00000000000406af R15: 00007ffd4847f2e0
 </TASK>
rcu: rcu_preempt kthread starved for 10543 jiffies! g21461 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:27656 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5282 [inline]
 __schedule+0x14db/0x5030 kernel/sched/core.c:6894
 __schedule_loop kernel/sched/core.c:6976 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6991
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x11b0 kernel/rcu/tree.c:2095
 rcu_gp_kthread+0x9b/0x2d0 kernel/rcu/tree.c:2297
 kthread+0x389/0x480 kernel/kthread.c:467
 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 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:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d e3 3f 29 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffffff8de07dc0 EFLAGS: 000002c2
RAX: 00000000007f9b8b RBX: ffffffff81977eae RCX: 0000000080000001
RDX: 0000000000000001 RSI: ffffffff8d9a99b4 RDI: ffffffff8be09d60
RBP: ffffffff8de07eb0 R08: ffff8880b863375b R09: 1ffff110170c66eb
R10: dffffc0000000000 R11: ffffed10170c66ec R12: ffffffff8fa2d8f0
R13: 1ffffffff1bd29d0 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888125bf7000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c37818c CR3: 000000002f64e000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:767
 default_idle_call+0x73/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:191 [inline]
 do_idle+0x1be/0x4d0 kernel/sched/idle.c:332
 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430
 rest_init+0x2de/0x300 init/main.c:758
 start_kernel+0x38b/0x3e0 init/main.c:1209
 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
 common_startup_64+0x13e/0x147
 </TASK>