syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P6821/1:b..l P6829/1:b..l P6835/1:b..l
rcu: 	(detected by 0, t=10503 jiffies, g=19113, q=996634 ncpus=2)
task:syz.1.232       state:R  running task     stack:24968 pid:6835  tgid:6826  ppid:5874   task_flags:0x400040 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7288
 irqentry_exit+0x6f/0x90 kernel/entry/common.c:197
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
RIP: 0010:rcu_is_watching+0x6c/0xb0 kernel/rcu/tree.c:751
Code: 7c 00 48 c7 c3 98 7f a1 92 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38 84 c0 75 34 8b 03 65 ff 0d 99 f2 f9 10 74 11 83 e0 04 <c1> e8 02 5b 41 5e 41 5f c3 cc cc cc cc cc e8 81 69 8d ff eb e8 48
RSP: 0018:ffffc9000daae998 EFLAGS: 00000202
RAX: 0000000000000004 RBX: ffff8880b8632f98 RCX: b7077157f2f03a00
RDX: 0000000000000000 RSI: ffffffff8be33760 RDI: ffffffff8be33720
RBP: dffffc0000000000 R08: 0000000000000000 R09: ffffffff8172c195
R10: ffffc9000daaead8 R11: ffffffff81ac3820 R12: 1ffff92001b55d51
R13: ffffc9000daaeac0 R14: ffffffff8dbdfd10 R15: dffffc0000000000
 rcu_read_lock include/linux/rcupdate.h:842 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1155 [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/0x4a0 mm/page_owner.c:329
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1851
 prep_new_page mm/page_alloc.c:1859 [inline]
 get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3858
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5148
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416
 folio_alloc_mpol_noprof mm/mempolicy.c:2435 [inline]
 vma_alloc_folio_noprof+0xe4/0x200 mm/mempolicy.c:2470
 folio_prealloc+0x30/0x180 mm/memory.c:-1
 wp_page_copy mm/memory.c:3552 [inline]
 do_wp_page+0x1231/0x5800 mm/memory.c:4013
 handle_pte_fault mm/memory.c:6068 [inline]
 __handle_mm_fault+0x1033/0x5440 mm/memory.c:6195
 handle_mm_fault+0x40a/0x8e0 mm/memory.c:6364
 do_user_addr_fault+0x764/0x1390 arch/x86/mm/fault.c:1387
 handle_page_fault arch/x86/mm/fault.c:1476 [inline]
 exc_page_fault+0x76/0xf0 arch/x86/mm/fault.c:1532
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0010:__put_user_nocheck_4+0x3/0x10 arch/x86/lib/putuser.S:104
Code: d9 0f 01 cb 89 01 31 c9 0f 01 ca c3 cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 01 cb <89> 01 31 c9 0f 01 ca e9 01 44 03 00 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9000daaf8b8 EFLAGS: 00050202
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000200000061030
RDX: ffff88802c9f3c00 RSI: 0000000000000002 RDI: 00000000ffffffff
RBP: ffffc9000daafa30 R08: ffffc9000daaf667 R09: 1ffff92001b55ecc
R10: dffffc0000000000 R11: fffff52001b55ecd R12: 0000000000000002
R13: dffffc0000000000 R14: 0000000000000000 R15: 0000200000061000
 ____sys_recvmsg+0x2ab/0x460 net/socket.c:2847
 ___sys_recvmsg+0x1b5/0x510 net/socket.c:2876
 do_recvmmsg+0x307/0x770 net/socket.c:2971
 __sys_recvmmsg net/socket.c:3045 [inline]
 __do_sys_recvmmsg net/socket.c:3068 [inline]
 __se_sys_recvmmsg net/socket.c:3061 [inline]
 __x64_sys_recvmmsg+0x190/0x240 net/socket.c:3061
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f07e1d8ebe9
RSP: 002b:00007f07e2bd8038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007f07e1fb6090 RCX: 00007f07e1d8ebe9
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000006
RBP: 00007f07e1e11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f07e1fb6128 R14: 00007f07e1fb6090 R15: 00007f07e20dfa28
 </TASK>
task:syz.2.231       state:R  running task     stack:26888 pid:6829  tgid:6828  ppid:5873   task_flags:0x40044c flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7145
 preempt_schedule+0xae/0xc0 kernel/sched/core.c:7169
 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]
 zap_pte_range mm/memory.c:1756 [inline]
 zap_pmd_range mm/memory.c:1818 [inline]
 zap_pud_range mm/memory.c:1847 [inline]
 zap_p4d_range mm/memory.c:1868 [inline]
 unmap_page_range+0x3a79/0x4370 mm/memory.c:1889
 unmap_single_vma mm/memory.c:1932 [inline]
 unmap_vmas+0x399/0x580 mm/memory.c:1976
 exit_mmap+0x248/0xb50 mm/mmap.c:1280
 __mmput+0x118/0x420 kernel/fork.c:1130
 exit_mm+0x1da/0x2c0 kernel/exit.c:582
 do_exit+0x648/0x2300 kernel/exit.c:949
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1102
 get_signal+0x1286/0x1340 kernel/signal.c:3034
 arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:40
 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/0x3b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f35e198e7eb
RSP: 002b:00007f35e272ef10 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007f35e198e7eb
RDX: 00007f35e272ffe0 RSI: 0000000080085502 RDI: 0000000000000003
RBP: 00007f35e272ffe0 R08: 0000000000000080 R09: 00007f35e272efd8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000080085502
R13: 0000000800000000 R14: 0000000000000009 R15: 00007f35e1a1d391
 </TASK>
task:syz.4.229       state:R  running task     stack:24104 pid:6821  tgid:6821  ppid:5870   task_flags:0x400040 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
 preempt_schedule_notrace+0xd1/0x110 kernel/sched/core.c:7238
 preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13
 rcu_is_watching+0x7f/0xb0 kernel/rcu/tree.c:752
 rcu_read_unlock include/linux/rcupdate.h:869 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1155 [inline]
 unwind_next_frame+0x1965/0x2390 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:308
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1395 [inline]
 __free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2895
 __slab_free+0x303/0x3c0 mm/slub.c:4591
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:340
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4180 [inline]
 slab_alloc_node mm/slub.c:4229 [inline]
 __do_kmalloc_node mm/slub.c:4364 [inline]
 __kmalloc_noprof+0x224/0x4f0 mm/slub.c:4377
 kmalloc_noprof include/linux/slab.h:909 [inline]
 kmalloc_array_noprof include/linux/slab.h:948 [inline]
 snd_pcm_plugin_build+0x267/0x500 sound/core/oss/pcm_plugin.c:181
 snd_pcm_plugin_build_io+0x1d9/0x5f0 sound/core/oss/io.c:124
 snd_pcm_oss_change_params_locked+0x2364/0x3e40 sound/core/oss/pcm_oss.c:983
 snd_pcm_oss_change_params sound/core/oss/pcm_oss.c:1104 [inline]
 snd_pcm_oss_make_ready+0x11b/0x340 sound/core/oss/pcm_oss.c:1163
 snd_pcm_oss_sync+0x19b/0xc30 sound/core/oss/pcm_oss.c:1729
 snd_pcm_oss_release+0xff/0x250 sound/core/oss/pcm_oss.c:2574
 __fput+0x44c/0xa70 fs/file_table.c:468
 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+0xec/0x110 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/0x3b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa15098ebe9
RSP: 002b:00007fa150cdfb88 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007fa150bb7da0 RCX: 00007fa15098ebe9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007fa150bb7da0 R08: 0000000000010ef4 R09: 0000001c50cdfe7f
R10: 00007fa150bb7cb0 R11: 0000000000000246 R12: 000000000002a403
R13: 00007fa150bb6270 R14: ffffffffffffffff R15: 00007fa150cdfca0
 </TASK>
rcu: rcu_preempt kthread starved for 5917 jiffies! g19113 f0x2 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:26792 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
 __schedule_loop kernel/sched/core.c:7043 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7058
 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+0x70e/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:217 [inline]
RIP: 0010:unwind_next_frame+0x214/0x2390 arch/x86/kernel/unwind_orc.c:494
Code: ef 08 8b 15 1e 3f 4b 0c 8d 42 ff 44 39 f8 0f 86 65 18 00 00 44 89 f8 4c 8d 2c 85 38 19 e0 90 4c 89 e8 48 c1 e8 03 0f b6 04 28 <84> c0 48 89 eb 0f 85 1c 1c 00 00 45 8b 6d 00 44 89 f8 ff c0 48 8d
RSP: 0018:ffffc90000006bf8 EFLAGS: 00000a07
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 99d1df192f91dd00
RDX: 00000000000a7d74 RSI: ffffffff8be33760 RDI: ffffffff8be33720
RBP: dffffc0000000000 R08: 0000000000000000 R09: ffffffff8172c195
R10: ffffc90000006d18 R11: ffffffff81ac3820 R12: ffffffff8b799f05
R13: ffffffff9109ffb4 R14: ffffc90000006cc8 R15: 00000000000a799f
FS:  0000000000000000(0000) GS:ffff888125c1b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000258030 CR3: 000000007eb4a000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 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:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:243 [inline]
 __kasan_slab_free+0x5b/0x80 mm/kasan/common.c:275
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2417 [inline]
 slab_free mm/slub.c:4680 [inline]
 kfree+0x18e/0x440 mm/slub.c:4879
 ieee80211_inform_bss+0xbd9/0x10a0 net/mac80211/scan.c:160
 rdev_inform_bss net/wireless/rdev-ops.h:418 [inline]
 cfg80211_inform_single_bss_data+0xd02/0x1ac0 net/wireless/scan.c:2379
 cfg80211_inform_bss_data+0x1fb/0x3b30 net/wireless/scan.c:3234
 cfg80211_inform_bss_frame_data+0x3d7/0x730 net/wireless/scan.c:3325
 ieee80211_bss_info_update+0x746/0x9e0 net/mac80211/scan.c:226
 ieee80211_scan_rx+0x593/0xa20 net/mac80211/scan.c:355
 __ieee80211_rx_handle_packet net/mac80211/rx.c:5186 [inline]
 ieee80211_rx_list+0x201c/0x2a90 net/mac80211/rx.c:5423
 ieee80211_rx_napi+0x1a8/0x3d0 net/mac80211/rx.c:5446
 ieee80211_rx include/net/mac80211.h:5210 [inline]
 ieee80211_handle_queued_frames+0xe8/0x1f0 net/mac80211/main.c:453
 tasklet_action_common+0x369/0x580 kernel/softirq.c:829
 handle_softirqs+0x283/0x870 kernel/softirq.c:579
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1050
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: 53 e7 02 00 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 f3 86 0e 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:ffffffff8de07d80 EFLAGS: 000002c2
RAX: 99d1df192f91dd00 RBX: ffffffff819683c8 RCX: 99d1df192f91dd00
RDX: 0000000000000001 RSI: ffffffff8d9b7d7a RDI: ffffffff8be33780
RBP: ffffffff8de07eb8 R08: ffff8880b8632f9b R09: 1ffff110170c65f3
R10: dffffc0000000000 R11: ffffed10170c65f4 R12: ffffffff8fa38c30
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1bd2a20
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:757
 default_idle_call+0x74/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:190 [inline]
 do_idle+0x1e8/0x510 kernel/sched/idle.c:330
 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428
 rest_init+0x2de/0x300 init/main.c:744
 start_kernel+0x3a9/0x410 init/main.c:1097
 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:307
 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:288
 common_startup_64+0x13e/0x147
 </TASK>