rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P29981/1:b..l P28910/1:b..l P29977/1:b..l P134/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=137481, q=763 ncpus=2)
task:kworker/u8:5    state:R  running task     stack:23080 pid:134   tgid:134   ppid:2      task_flags:0x4208160 flags:0x00080000
Workqueue: iou_exit io_ring_exit_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x1139/0x6150 kernel/sched/core.c:6863
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7190
 irqentry_exit+0x1d8/0x8c0 kernel/entry/common.c:216
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_release+0x183/0x2d0 kernel/locking/lockdep.c:5893
Code: 0f c1 05 48 01 19 12 83 f8 01 0f 85 03 01 00 00 9c 58 f6 c4 02 0f 85 ee 00 00 00 41 f7 c5 00 02 00 00 74 01 fb 48 8b 44 24 10 <65> 48 2b 05 dd b9 18 12 0f 85 32 01 00 00 48 83 c4 18 5b 41 5c 41
RSP: 0018:ffffc90002e77510 EFLAGS: 00000206
RAX: 2ab424c35d538600 RBX: ffffffff8e3c9620 RCX: ffffc90002e7751c
RDX: 0000000000000003 RSI: ffffffff8daa7d80 RDI: ffffffff8bf2b380
RBP: 0000000000000001 R08: 0000000000000001 R09: 00000000e3ebf034
R10: 0000000000000002 R11: 00000000000061ed R12: ffffffff816cb9a4
R13: 0000000000000206 R14: ffff88801e378000 R15: 0000000000000004
 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+0x3f9/0x20b0 arch/x86/kernel/unwind_orc.c:495
 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
 kasan_save_track+0x14/0x30 mm/kasan/common.c:77
 poison_kmalloc_redzone mm/kasan/common.c:397 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:414
 kmalloc_noprof include/linux/slab.h:957 [inline]
 slab_free_hook mm/slub.c:2492 [inline]
 slab_free mm/slub.c:6668 [inline]
 kmem_cache_free+0x147/0x770 mm/slub.c:6779
 __io_req_caches_free+0x19e/0x5c0 io_uring/io_uring.c:2826
 io_req_caches_free io_uring/io_uring.c:2838 [inline]
 io_ring_exit_work+0x33c/0x1130 io_uring/io_uring.c:3024
 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257
 process_scheduled_works kernel/workqueue.c:3340 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
task:syz.5.6882      state:R  running task     stack:25984 pid:29977 tgid:29977 ppid:26498  task_flags:0x40004c flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x1139/0x6150 kernel/sched/core.c:6863
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7190
 irqentry_exit+0x1d8/0x8c0 kernel/entry/common.c:216
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:unwind_next_frame+0x161d/0x20b0 arch/x86/kernel/unwind_orc.c:680
Code: 89 e2 48 89 c5 48 c1 ea 03 48 b8 00 00 00 00 00 fc ff df 80 3c 02 00 0f 84 31 f8 ff ff 4c 89 e7 e8 b8 f5 bb 00 e9 24 f8 ff ff <48> b8 00 00 00 00 00 fc ff df 48 8b 14 24 48 c1 ea 03 80 3c 02 00
RSP: 0018:ffffc9000db77830 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffc9000db78000
RDX: 1ffff92001b6ef14 RSI: ffffc9000db77ed8 RDI: ffffc9000db778e0
RBP: ffffc9000db77f38 R08: 0000000000000001 R09: 000000002d64dbdc
R10: 0000000000000002 R11: 0000000000007d7e R12: ffffc9000db778f0
R13: ffffc9000db778a0 R14: ffffc9000db77f00 R15: ffffc9000db778d4
 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 save_stack+0x160/0x1f0 mm/page_owner.c:165
 __reset_page_owner+0x84/0x1a0 mm/page_owner.c:320
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1395 [inline]
 __free_frozen_pages+0x7df/0x1170 mm/page_alloc.c:2943
 tlb_batch_list_free mm/mmu_gather.c:159 [inline]
 tlb_finish_mmu+0x237/0x7c0 mm/mmu_gather.c:500
 exit_mmap+0x3f9/0xb60 mm/mmap.c:1290
 __mmput+0x12a/0x410 kernel/fork.c:1173
 mmput+0x62/0x70 kernel/fork.c:1196
 exit_mm kernel/exit.c:581 [inline]
 do_exit+0x7d7/0x2bd0 kernel/exit.c:959
 do_group_exit+0xd3/0x2a0 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+0x3e/0x50 kernel/exit.c:1121
 x64_sys_call+0x151c/0x1740 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2ca9f8f749
RSP: 002b:00007ffd77b00f38 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f2ca9f8f749
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffd77b00f9c R08: 0000000c77b0102f R09: 00000000000927c0
R10: 000000000000d8b8 R11: 0000000000000246 R12: 00000000000000a4
R13: 00000000000927c0 R14: 00000000001c7866 R15: 00007ffd77b00ff0
 </TASK>
task:kworker/u8:23   state:R  running task     stack:25168 pid:28910 tgid:28910 ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x1139/0x6150 kernel/sched/core.c:6863
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7190
 irqentry_exit+0x1d8/0x8c0 kernel/entry/common.c:216
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:deref_stack_reg arch/x86/kernel/unwind_orc.c:422 [inline]
RIP: 0010:unwind_next_frame+0xbae/0x20b0 arch/x86/kernel/unwind_orc.c:600
Code: ff 48 8b 7c 24 18 e8 51 ea ff ff 48 89 ee 48 8b 4c 24 20 48 ba 00 00 00 00 00 fc ff df 48 c1 ee 03 4c 8b 44 24 28 80 3c 16 00 <0f> 85 e4 10 00 00 48 8b 14 24 49 89 45 48 48 b8 00 00 00 00 00 fc
RSP: 0018:ffffc9000d8c74f8 EFLAGS: 00000246
RAX: ffffffff8b3f9f3d RBX: 0000000000000001 RCX: ffffffff91b148a8
RDX: dffffc0000000000 RSI: 1ffff92001b18eb6 RDI: ffffc9000d8c79d0
RBP: ffffc9000d8c75b0 R08: ffffffff91b148ac R09: 00000000abe50334
R10: 0000000000000002 R11: 0000000000083ffd R12: ffffc9000d8c75b8
R13: ffffc9000d8c7568 R14: ffffc9000d8c79d8 R15: ffffc9000d8c759c
 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
 kasan_save_track+0x14/0x30 mm/kasan/common.c:77
 unpoison_slab_object mm/kasan/common.c:339 [inline]
 __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:365
 kasan_slab_alloc include/linux/kasan.h:252 [inline]
 slab_post_alloc_hook mm/slub.c:4953 [inline]
 slab_alloc_node mm/slub.c:5263 [inline]
 kmem_cache_alloc_noprof+0x25e/0x770 mm/slub.c:5270
 __build_skb+0x3f/0x90 net/core/skbuff.c:474
 __netdev_alloc_skb+0x22d/0x920 net/core/skbuff.c:784
 __netdev_alloc_skb_ip_align include/linux/skbuff.h:3504 [inline]
 netdev_alloc_skb_ip_align include/linux/skbuff.h:3514 [inline]
 batadv_iv_ogm_aggregate_new+0x10d/0x4c0 net/batman-adv/bat_iv_ogm.c:566
 batadv_iv_ogm_queue_add net/batman-adv/bat_iv_ogm.c:677 [inline]
 batadv_iv_ogm_schedule_buff+0x9c2/0x14c0 net/batman-adv/bat_iv_ogm.c:841
 batadv_iv_ogm_schedule net/batman-adv/bat_iv_ogm.c:873 [inline]
 batadv_iv_ogm_schedule net/batman-adv/bat_iv_ogm.c:866 [inline]
 batadv_iv_send_outstanding_bat_ogm_packet+0x329/0x920 net/batman-adv/bat_iv_ogm.c:1709
 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257
 process_scheduled_works kernel/workqueue.c:3340 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
task:syz.2.6883      state:R  running task     stack:25072 pid:29981 tgid:29980 ppid:25502  task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x1139/0x6150 kernel/sched/core.c:6863
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7190
 irqentry_exit+0x1d8/0x8c0 kernel/entry/common.c:216
 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_release+0x183/0x2d0 kernel/locking/lockdep.c:5893
Code: 0f c1 05 48 01 19 12 83 f8 01 0f 85 03 01 00 00 9c 58 f6 c4 02 0f 85 ee 00 00 00 41 f7 c5 00 02 00 00 74 01 fb 48 8b 44 24 10 <65> 48 2b 05 dd b9 18 12 0f 85 32 01 00 00 48 83 c4 18 5b 41 5c 41
RSP: 0000:ffffc9000fc8f520 EFLAGS: 00000206
RAX: c70560333cb6a600 RBX: ffffffff8e3c9620 RCX: ffffc9000fc8f52c
RDX: 0000000000000001 RSI: ffffffff8daa7d80 RDI: ffffffff8bf2b380
RBP: 0000000000000001 R08: 0000000000000001 R09: 000000004e8bb507
R10: 0000000000000002 R11: 0000000000011d33 R12: ffffffff816cb9a4
R13: 0000000000000206 R14: ffff88802cad0000 R15: 0000000000000002
 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+0x3f9/0x20b0 arch/x86/kernel/unwind_orc.c:495
 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
 kasan_save_track+0x14/0x30 mm/kasan/common.c:77
 unpoison_slab_object mm/kasan/common.c:339 [inline]
 __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:365
 kasan_slab_alloc include/linux/kasan.h:252 [inline]
 slab_post_alloc_hook mm/slub.c:4953 [inline]
 slab_alloc_node mm/slub.c:5263 [inline]
 kmem_cache_alloc_node_noprof+0x298/0x800 mm/slub.c:5315
 __alloc_skb+0x156/0x410 net/core/skbuff.c:679
 alloc_skb_fclone include/linux/skbuff.h:1433 [inline]
 tcp_stream_alloc_skb+0x34/0x670 net/ipv4/tcp.c:910
 tcp_sendmsg_locked+0x12de/0x42a0 net/ipv4/tcp.c:1217
 tcp_sendmsg+0x2e/0x50 net/ipv4/tcp.c:1412
 inet_sendmsg+0xb9/0x140 net/ipv4/af_inet.c:859
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg net/socket.c:742 [inline]
 __sys_sendto+0x43c/0x520 net/socket.c:2206
 __do_sys_sendto net/socket.c:2213 [inline]
 __se_sys_sendto net/socket.c:2209 [inline]
 __x64_sys_sendto+0xe0/0x1c0 net/socket.c:2209
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2e60b8f749
RSP: 002b:00007f2e61ac2038 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f2e60de5fa0 RCX: 00007f2e60b8f749
RDX: 12571144d43d7ee5 RSI: 0000200000000580 RDI: 0000000000000003
RBP: 00007f2e60c13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000010008095 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2e60de6038 R14: 00007f2e60de5fa0 R15: 00007ffe1722aab8
 </TASK>
rcu: rcu_preempt kthread starved for 10653 jiffies! g137481 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:28064 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x1139/0x6150 kernel/sched/core.c:6863
 __schedule_loop kernel/sched/core.c:6945 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6960
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x983/0xb10 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 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82
Code: c6 5f 02 c3 cc cc cc cc 0f 1f 00 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 13 49 12 00 fb f4 <e9> cc 35 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffffff8e007df8 EFLAGS: 000002c6
RAX: 00000000046b8e0b RBX: 0000000000000000 RCX: ffffffff8b7816d9
RDX: 0000000000000000 RSI: ffffffff8dacde18 RDI: ffffffff8bf2b380
RBP: fffffbfff1c12f68 R08: 0000000000000001 R09: ffffed101708673d
R10: ffff8880b84339eb R11: ffffffff8e098670 R12: 0000000000000000
R13: ffffffff8e097b40 R14: ffffffff9088b3d0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8881248f5000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2ea07ff8 CR3: 00000000658d8000 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+0x6c/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:191 [inline]
 do_idle+0x38d/0x510 kernel/sched/idle.c:332
 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430
 rest_init+0x16b/0x2b0 init/main.c:757
 start_kernel+0x3ef/0x4d0 init/main.c:1206
 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:310
 x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:291
 common_startup_64+0x13e/0x148
 </TASK>