rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P19211/1:b..l rcu: (detected by 1, t=10502 jiffies, g=92181, q=325 ncpus=2) task:syz.6.3820 state:R running task stack:26584 pid:19211 tgid:19207 ppid:12429 task_flags:0x400040 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5360 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6964 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7291 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:mas_start+0x25f/0x560 lib/maple_tree.c:1202 Code: 48 8b 44 24 38 0f b6 04 28 84 c0 0f 85 0e 01 00 00 48 8b 44 24 10 c6 00 00 48 8b 44 24 20 0f b6 04 28 84 c0 0f 85 14 01 00 00 <41> c7 07 00 00 00 00 48 8b 44 24 28 80 3c 28 00 74 08 4c 89 ef e8 RSP: 0018:ffffc9000e2bf488 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffc9000e2bf560 RCX: ffff88801e36dac0 RDX: 0000000000000002 RSI: 0000000000000002 RDI: 0000000000000002 RBP: dffffc0000000000 R08: 0000000000000000 R09: ffffffff8b7c1dfc R10: dffffc0000000000 R11: fffffbfff1f88787 R12: ffff88807c3f101e R13: ffffc9000e2bf578 R14: 0000000000000002 R15: ffffc9000e2bf5a8 mas_state_walk lib/maple_tree.c:3289 [inline] mt_find+0x216/0x5e0 lib/maple_tree.c:6495 find_vma+0xe7/0x160 mm/mmap.c:909 lock_mm_and_find_vma+0x5f/0x300 mm/mmap_lock.c:431 do_user_addr_fault+0x331/0x1390 arch/x86/mm/fault.c:1359 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: 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 11 65 03 00 90 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc9000e2bf8b8 EFLAGS: 00050202 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 000020000004c030 RDX: ffff88801e36dac0 RSI: 0000000000000002 RDI: 00000000ffffffff RBP: ffffc9000e2bfa30 R08: ffffc9000e2bf667 R09: 1ffff92001c57ecc R10: dffffc0000000000 R11: fffff52001c57ecd R12: 0000000000000002 R13: dffffc0000000000 R14: 0000000000000000 R15: 000020000004c000 ____sys_recvmsg+0x2ab/0x460 net/socket.c:2850 ___sys_recvmsg+0x1b5/0x510 net/socket.c:2879 do_recvmmsg+0x307/0x770 net/socket.c:2974 __sys_recvmmsg net/socket.c:3048 [inline] __do_sys_recvmmsg net/socket.c:3071 [inline] __se_sys_recvmmsg net/socket.c:3064 [inline] __x64_sys_recvmmsg+0x190/0x240 net/socket.c:3064 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: 0033:0x7f22c9d8eba9 RSP: 002b:00007f22cacda038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f22c9fd6090 RCX: 00007f22c9d8eba9 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000003 RBP: 00007f22c9e11e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f22c9fd6128 R14: 00007f22c9fd6090 R15: 00007fff371f3428 rcu: rcu_preempt kthread starved for 10548 jiffies! g92181 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:27256 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5360 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6964 __schedule_loop kernel/sched/core.c:7046 [inline] schedule+0x165/0x360 kernel/sched/core.c:7061 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 08/18/2025 RIP: 0010:unwind_next_frame+0x50f/0x2390 arch/x86/kernel/unwind_orc.c:512 Code: 18 00 00 4c 89 e0 48 c1 e8 03 0f b6 04 28 84 c0 0f 85 63 18 00 00 0f b7 1e c1 eb 0b 80 e3 01 48 8b 44 24 28 0f b6 04 28 84 c0 <4c> 8b 7c 24 70 0f 85 6d 18 00 00 48 8b 44 24 10 88 18 0f b7 1e 83 RSP: 0018:ffffc90000a07978 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff90429d88 RDX: ffffffff90f4104a RSI: ffffffff90f4104e RDI: ffffffff8c037da0 RBP: dffffc0000000000 R08: 0000000000000009 R09: ffffffff8173bd25 R10: ffffc90000a07a98 R11: ffffffff81ac4710 R12: ffffffff90f4104f R13: ffffc90000a07a98 R14: ffffc90000a07a48 R15: ffffffff8173bd25 FS: 0000000000000000(0000) GS:ffff888125ae1000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c43ac3e CR3: 0000000077886000 CR4: 00000000003526f0 Call Trace: 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:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 unpoison_slab_object mm/kasan/common.c:342 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:368 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4927 [inline] slab_alloc_node mm/slub.c:5226 [inline] kmem_cache_alloc_noprof+0x367/0x6e0 mm/slub.c:5233 kmem_alloc_batch lib/debugobjects.c:371 [inline] fill_pool+0x100/0x570 lib/debugobjects.c:403 debug_objects_fill_pool lib/debugobjects.c:725 [inline] debug_object_activate+0x383/0x420 lib/debugobjects.c:814 debug_rcu_head_queue kernel/rcu/rcu.h:236 [inline] kvfree_call_rcu+0xc4/0x4c0 mm/slab_common.c:1986 cfg80211_update_known_bss+0x830/0x1590 net/wireless/scan.c:1944 __cfg80211_bss_update+0x147/0x2120 net/wireless/scan.c:1989 cfg80211_inform_single_bss_data+0xba9/0x1ac0 net/wireless/scan.c:2381 cfg80211_inform_bss_data+0x1fb/0x3b30 net/wireless/scan.c:3240 cfg80211_inform_bss_frame_data+0x3d7/0x730 net/wireless/scan.c:3331 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+0x36c/0x580 kernel/softirq.c:829 handle_softirqs+0x286/0x870 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:1052 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1052 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 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 03 7c 24 00 f3 0f 1e fa fb f4 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90000197de0 EFLAGS: 000002c2 RAX: ee8733406aa89d00 RBX: ffffffff819697b8 RCX: ee8733406aa89d00 RDX: 0000000000000001 RSI: ffffffff8dbc0cb8 RDI: ffffffff8c037e00 RBP: ffffc90000197f10 R08: ffff8880b8732fdb R09: 1ffff110170e65fb R10: dffffc0000000000 R11: ffffed10170e65fc R12: ffffffff8fc43c30 R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff1100395cb58 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 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 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:315 common_startup_64+0x13e/0x147