rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6103/1:b..l P6055/1:b..l P5832/1:b..l P5834/1:b..l rcu: (detected by 1, t=10502 jiffies, g=13085, q=1049 ncpus=2) task:syz-executor state:R running task stack:21672 pid:5834 tgid:5834 ppid:5828 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7113 preempt_schedule+0xae/0xc0 kernel/sched/core.c:7137 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] copy_pte_range mm/memory.c:1329 [inline] copy_pmd_range+0x7630/0x7f00 mm/memory.c:1389 copy_pud_range mm/memory.c:1426 [inline] copy_p4d_range mm/memory.c:1450 [inline] copy_page_range+0xc14/0x1270 mm/memory.c:1538 dup_mmap+0xf4c/0x1b10 mm/mmap.c:1834 dup_mm kernel/fork.c:1489 [inline] copy_mm+0x13c/0x4b0 kernel/fork.c:1541 copy_process+0x1706/0x3c00 kernel/fork.c:2181 kernel_clone+0x21e/0x840 kernel/fork.c:2609 __do_sys_clone kernel/fork.c:2750 [inline] __se_sys_clone kernel/fork.c:2734 [inline] __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2734 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f8a7af85713 RSP: 002b:00007ffdff4a1358 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f8a7af85713 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 000055556756a7d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 000000000001f483 R15: 00007ffdff4a14f0 task:syz-executor state:R running task stack:20312 pid:5832 tgid:5832 ppid:5824 task_flags:0x400140 flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256 irqentry_exit+0x6f/0x90 kernel/entry/common.c:211 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_release+0x2b5/0x3e0 kernel/locking/lockdep.c:5893 Code: 51 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 75 56 f7 c3 00 02 00 00 74 01 fb 65 48 8b 05 4b ba d0 10 <48> 3b 44 24 28 0f 85 8b 00 00 00 48 83 c4 30 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc9000409f0f0 EFLAGS: 00000206 RAX: f1cbde536e2ca100 RBX: 0000000000000206 RCX: f1cbde536e2ca100 RDX: 0000000000000000 RSI: ffffffff8d8f29f0 RDI: ffffffff8bbf05e0 RBP: ffff88802979e5f0 R08: ffffc9000409fcf8 R09: ffffc9000409f278 R10: dffffc0000000000 R11: fffff52000813e51 R12: 0000000000000000 R13: 0000000000000000 R14: ffffffff8df3d2e0 R15: ffff88802979dac0 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:897 [inline] class_rcu_destructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0x19a9/0x2390 arch/x86/kernel/unwind_orc.c:680 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 save_stack+0xf5/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:311 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1394 [inline] free_unref_folios+0xdb3/0x14f0 mm/page_alloc.c:2963 folios_put_refs+0x584/0x670 mm/swap.c:1002 folio_batch_release include/linux/pagevec.h:101 [inline] shmem_undo_range+0x49e/0x14b0 mm/shmem.c:1120 shmem_truncate_range mm/shmem.c:1232 [inline] shmem_evict_inode+0x272/0xa70 mm/shmem.c:1360 evict+0x504/0x9c0 fs/inode.c:810 __dentry_kill+0x209/0x660 fs/dcache.c:669 dput+0x19f/0x2b0 fs/dcache.c:911 __fput+0x68e/0xa70 fs/file_table.c:476 task_work_run+0x1d4/0x260 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop+0xe9/0x130 kernel/entry/common.c:43 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f963ad8dc2a RSP: 002b:00007ffcebf6f750 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007f963ad8dc2a RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007ffcebf6f7ac R08: 0000000000000000 R09: 00007ffcebf6f4b7 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000007 R13: 00000000000927c0 R14: 000000000001ecd2 R15: 00007ffcebf6f800 task:udevd state:R running task stack:24264 pid:6055 tgid:6055 ppid:5196 task_flags:0x400140 flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256 irqentry_exit+0x6f/0x90 kernel/entry/common.c:211 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:srso_alias_safe_ret+0x0/0x7 arch/x86/lib/retpoline.S:210 Code: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc <48> 8d 64 24 08 c3 cc e8 f4 ff ff ff 0f 0b cc cc cc cc cc cc cc cc RSP: 0018:ffffc9000aae7180 EFLAGS: 00000212 RAX: 0000000000000001 RBX: 00007f197d4a7407 RCX: 79aef24187408b00 RDX: ffff88801ff61e40 RSI: ffffffff8bbf05c0 RDI: ffffffff8bbf0580 RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff81cf13b6 R10: dffffc0000000000 R11: ffffffff81ac2d30 R12: ffff88801ff61e40 R13: 1ffff9200155ce70 R14: 00007f197d4a7407 R15: 1ffff9200155ce4e srso_alias_return_thunk+0x5/0xfbef5 arch/x86/lib/retpoline.S:220 rcu_read_lock include/linux/rcupdate.h:868 [inline] is_bpf_text_address+0x64/0x2b0 kernel/bpf/core.c:744 kernel_text_address+0xa5/0xe0 kernel/extable.c:125 __kernel_text_address+0xd/0x40 kernel/extable.c:79 unwind_get_return_address+0x4d/0x90 arch/x86/kernel/unwind_orc.c:369 arch_stack_walk+0xfc/0x150 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 save_stack+0xf5/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:311 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1394 [inline] free_unref_folios+0xdb3/0x14f0 mm/page_alloc.c:2963 folios_put_refs+0x584/0x670 mm/swap.c:1002 folio_batch_release include/linux/pagevec.h:101 [inline] shmem_undo_range+0x49e/0x14b0 mm/shmem.c:1120 shmem_truncate_range mm/shmem.c:1232 [inline] shmem_evict_inode+0x272/0xa70 mm/shmem.c:1360 evict+0x504/0x9c0 fs/inode.c:810 __dentry_kill+0x209/0x660 fs/dcache.c:669 dput+0x19f/0x2b0 fs/dcache.c:911 __fput+0x68e/0xa70 fs/file_table.c:476 task_work_run+0x1d4/0x260 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop+0xe9/0x130 kernel/entry/common.c:43 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f197d4a7407 RSP: 002b:00007ffe48fccf50 EFLAGS: 00000202 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 00007f197dba2880 RCX: 00007f197d4a7407 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000008 RBP: 00007f197dba26e8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000002 R13: 000055595365e190 R14: 0000000000000008 R15: 0000555953663e20 task:syz.3.38 state:R running task stack:25800 pid:6103 tgid:6100 ppid:5841 task_flags:0x400040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 preempt_schedule_notrace+0xd1/0x110 kernel/sched/core.c:7206 preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13 rcu_is_watching+0x7f/0xb0 kernel/rcu/tree.c:752 rcu_read_lock include/linux/rcupdate.h:868 [inline] class_rcu_constructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0xd4/0x2390 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 save_stack+0xf5/0x1f0 mm/page_owner.c:156 __set_page_owner+0x8d/0x4c0 mm/page_owner.c:332 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1850 prep_new_page mm/page_alloc.c:1858 [inline] get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3884 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5183 __alloc_pages_noprof mm/page_alloc.c:5217 [inline] alloc_pages_bulk_noprof+0x560/0x710 mm/page_alloc.c:5137 ___alloc_pages_bulk mm/kasan/shadow.c:345 [inline] __kasan_populate_vmalloc mm/kasan/shadow.c:370 [inline] kasan_populate_vmalloc+0xd1/0x270 mm/kasan/shadow.c:435 alloc_vmap_area+0xd7a/0x14c0 mm/vmalloc.c:2098 __get_vm_area_node+0x1f8/0x300 mm/vmalloc.c:3193 __vmalloc_node_range_noprof+0x30c/0x12d0 mm/vmalloc.c:3857 __vmalloc_node_noprof mm/vmalloc.c:3960 [inline] vmalloc_noprof+0xb2/0xf0 mm/vmalloc.c:3993 __snd_dma_alloc_pages sound/core/memalloc.c:45 [inline] snd_dma_alloc_dir_pages+0x120/0x220 sound/core/memalloc.c:79 do_alloc_pages+0x175/0x2c0 sound/core/pcm_memory.c:69 snd_pcm_lib_malloc_pages+0x303/0x690 sound/core/pcm_memory.c:455 snd_pcm_hw_params+0x7e5/0x1d30 sound/core/pcm_native.c:796 snd_pcm_oss_change_params_locked+0x21cb/0x3e40 sound/core/oss/pcm_oss.c:965 snd_pcm_oss_change_params sound/core/oss/pcm_oss.c:1104 [inline] snd_pcm_oss_get_active_substream+0x20b/0x280 sound/core/oss/pcm_oss.c:1121 snd_pcm_oss_get_channels sound/core/oss/pcm_oss.c:1815 [inline] snd_pcm_oss_set_channels+0x1b6/0x4d0 sound/core/oss/pcm_oss.c:1807 snd_pcm_oss_ioctl+0xadb/0xdd0 sound/core/oss/pcm_oss.c:2658 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3b0738efc9 RSP: 002b:00007f3b08184038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f3b075e6180 RCX: 00007f3b0738efc9 RDX: 0000200000000000 RSI: 00000000c0045006 RDI: 0000000000000003 RBP: 00007f3b07411f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f3b075e6218 R14: 00007f3b075e6180 R15: 00007ffd33271df8 rcu: rcu_preempt kthread starved for 10285 jiffies! g13085 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 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:27400 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0x165/0x360 kernel/sched/core.c:7026 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+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: 5e 33 ca f5 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 33 21 22 00 f3 0f 1e fa fb f4 33 33 ca f5 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90000197de0 EFLAGS: 000002c6 RAX: d919f7b373e6e600 RBX: ffffffff81967be7 RCX: d919f7b373e6e600 RDX: 0000000000000001 RSI: ffffffff8d70bf53 RDI: ffffffff8bbf05e0 RBP: ffffc90000197f10 R08: ffff8880b8932fdb R09: 1ffff110171265fb R10: dffffc0000000000 R11: ffffed10171265fc R12: ffffffff8f7cd470 R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff110038d8b58 FS: 0000000000000000(0000) GS:ffff88812623e000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00002000003f6030 CR3: 000000007d6b4000 CR4: 0000000000350ef0 Call Trace: 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:190 [inline] do_idle+0x1e7/0x510 kernel/sched/idle.c:330 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:315 common_startup_64+0x13e/0x147