rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P7963 rcu: (detected by 1, t=10503 jiffies, g=27465, q=406 ncpus=2) task:syz.7.587 state:R running task stack:24040 pid:7963 ppid:5963 flags:0x0000400a Call Trace: sched_show_task+0x49b/0x5c0 kernel/sched/core.c:9179 rcu_print_detail_task_stall_rnp kernel/rcu/tree_stall.h:261 [inline] print_other_cpu_stall+0xff9/0x1380 kernel/rcu/tree_stall.h:637 check_cpu_stall kernel/rcu/tree_stall.h:809 [inline] rcu_pending kernel/rcu/tree.c:3950 [inline] rcu_sched_clock_irq+0x88e/0x1230 kernel/rcu/tree.c:2295 update_process_times+0x147/0x1b0 kernel/time/timer.c:2072 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x3a2/0x580 kernel/time/tick-sched.c:1492 __run_hrtimer kernel/time/hrtimer.c:1750 [inline] __hrtimer_run_queues+0x4e1/0xc40 kernel/time/hrtimer.c:1814 hrtimer_interrupt+0x3c9/0x9c0 kernel/time/hrtimer.c:1876 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline] __sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline] sysvec_apic_timer_interrupt+0x51/0xc0 arch/x86/kernel/apic/apic.c:1088 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:bpf_tree_comp kernel/bpf/core.c:632 [inline] RIP: 0010:__lt_find include/linux/rbtree_latch.h:115 [inline] RIP: 0010:latch_tree_find include/linux/rbtree_latch.h:208 [inline] RIP: 0010:bpf_ksym_find kernel/bpf/core.c:708 [inline] RIP: 0010:is_bpf_text_address+0x135/0x2a0 kernel/bpf/core.c:742 Code: e3 03 8d 2c 5b 48 f7 dd 4d 8d a4 2f e0 fd ff ff 4c 89 e0 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 e7 e8 cf e3 4a 00 4d 8b 24 24 <4c> 89 e7 4c 89 f6 e8 80 aa f2 ff 4d 39 f4 76 0c e8 66 a8 f2 ff b8 RSP: 0018:ffffc900001f04a8 EFLAGS: 00000246 RAX: 1ffff110041ea229 RBX: 0000000000000000 RCX: ffff888024078000 RDX: 0000000000000100 RSI: 00007f35bdb9ce59 RDI: ffffffffa0004140 RBP: 0000000000000000 R08: dffffc0000000000 R09: 1ffffffff2238ea0 R10: dffffc0000000000 R11: fffffbfff2238ea1 R12: ffffffffa00040d8 R13: dffffc0000000000 R14: 00007f35bdb9ce59 R15: ffff888020f51368 kernel_text_address+0xa0/0xd0 kernel/extable.c:125 __kernel_text_address+0xd/0x30 kernel/extable.c:79 unwind_get_return_address+0x5d/0xc0 arch/x86/kernel/unwind_orc.c:369 arch_stack_walk+0x11d/0x190 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:53 kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:237 kasan_slab_free include/linux/kasan.h:164 [inline] slab_free_hook mm/slub.c:1811 [inline] slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837 slab_free mm/slub.c:3830 [inline] kmem_cache_free+0xf8/0x270 mm/slub.c:3852 tcp_write_queue_purge+0x143/0x2f0 net/ipv4/tcp.c:3007 tcp_done_with_error+0x43/0xc0 net/ipv4/tcp_input.c:4446 tcp_write_err net/ipv4/tcp_timer.c:72 [inline] tcp_write_timeout net/ipv4/tcp_timer.c:281 [inline] tcp_retransmit_timer+0x1728/0x3020 net/ipv4/tcp_timer.c:576 tcp_write_timer+0x12a/0x280 net/ipv4/tcp_timer.c:709 call_timer_fn+0x189/0x540 kernel/time/timer.c:1701 expire_timers kernel/time/timer.c:1752 [inline] __run_timers+0x542/0x800 kernel/time/timer.c:2023 run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2036 handle_softirqs+0x280/0x820 kernel/softirq.c:578 __do_softirq kernel/softirq.c:612 [inline] invoke_softirq kernel/softirq.c:452 [inline] __irq_exit_rcu+0xd3/0x190 kernel/softirq.c:661 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline] sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:check_kcov_mode kernel/kcov.c:182 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x17/0x60 kernel/kcov.c:216 Code: 48 8b 3d 7c 0a 04 0d 48 89 de 5b e9 f3 6b 57 00 cc cc cc f3 0f 1e fa 48 8b 04 24 65 48 8b 0d 10 8e 7c 7e 65 8b 15 11 8e 7c 7e <81> e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 1c 16 00 00 RSP: 0018:ffffc90011f77700 EFLAGS: 00000283 RAX: ffffffff813b6e19 RBX: ffffc90011f77cb0 RCX: ffff888024078000 RDX: 0000000080000001 RSI: 0000000000015528 RDI: ffffc90011f77cb0 RBP: ffffc90011f77838 R08: ffff888024078000 R09: 0000000000000003 R10: 0000000000000004 R11: 0000000000000002 R12: ffffc90011f777e8 R13: dffffc0000000000 R14: ffffc90011f77cb0 R15: ffffffff8f1a05a6 __read_once_word_nocheck+0x9/0x10 include/asm-generic/rwonce.h:66 deref_stack_reg arch/x86/kernel/unwind_orc.c:406 [inline] unwind_next_frame+0x15f9/0x2970 arch/x86/kernel/unwind_orc.c:585 arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122 save_stack+0x125/0x230 mm/page_owner.c:128 __reset_page_owner+0x4e/0x190 mm/page_owner.c:149 reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1181 [inline] free_unref_page_prepare+0x7b2/0x8c0 mm/page_alloc.c:2365 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2458 discard_slab mm/slub.c:2127 [inline] __unfreeze_partials+0x1cf/0x210 mm/slub.c:2667 put_cpu_partial+0x17c/0x250 mm/slub.c:2743 __slab_free+0x319/0x400 mm/slub.c:3700 qlink_free mm/kasan/quarantine.c:166 [inline] qlist_free_all+0x75/0xd0 mm/kasan/quarantine.c:185 kasan_quarantine_reduce+0x143/0x160 mm/kasan/quarantine.c:292 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:306 kasan_slab_alloc include/linux/kasan.h:188 [inline] slab_post_alloc_hook+0x6e/0x4b0 mm/slab.h:767 slab_alloc_node mm/slub.c:3495 [inline] slab_alloc mm/slub.c:3503 [inline] __kmem_cache_alloc_lru mm/slub.c:3510 [inline] kmem_cache_alloc_lru+0x111/0x2d0 mm/slub.c:3526 alloc_inode_sb include/linux/fs.h:2946 [inline] sock_alloc_inode+0x28/0xc0 net/socket.c:308 alloc_inode fs/inode.c:261 [inline] new_inode_pseudo+0x63/0x1d0 fs/inode.c:1049 sock_alloc net/socket.c:634 [inline] __sock_create+0x12d/0x940 net/socket.c:1534 sock_create net/socket.c:1626 [inline] __sys_socketpair+0x1c1/0x550 net/socket.c:1777 __do_sys_socketpair net/socket.c:1830 [inline] __se_sys_socketpair net/socket.c:1827 [inline] __x64_sys_socketpair+0x9b/0xb0 net/socket.c:1827 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f35bdb9ce59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f35be9c3028 EFLAGS: 00000246 ORIG_RAX: 0000000000000035 RAX: ffffffffffffffda RBX: 00007f35bde15fa0 RCX: 00007f35bdb9ce59 RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000001 RBP: 00007f35bdc32d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000200000000040 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f35bde16038 R14: 00007f35bde15fa0 R15: 00007ffdbc44b588 rcu: rcu_preempt kthread starved for 10550 jiffies! g27465 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:26248 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x313/0x1590 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 PID: 7963 Comm: syz.7.587 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:bpf_tree_comp kernel/bpf/core.c:632 [inline] RIP: 0010:__lt_find include/linux/rbtree_latch.h:115 [inline] RIP: 0010:latch_tree_find include/linux/rbtree_latch.h:208 [inline] RIP: 0010:bpf_ksym_find kernel/bpf/core.c:708 [inline] RIP: 0010:is_bpf_text_address+0x135/0x2a0 kernel/bpf/core.c:742 Code: e3 03 8d 2c 5b 48 f7 dd 4d 8d a4 2f e0 fd ff ff 4c 89 e0 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 e7 e8 cf e3 4a 00 4d 8b 24 24 <4c> 89 e7 4c 89 f6 e8 80 aa f2 ff 4d 39 f4 76 0c e8 66 a8 f2 ff b8 RSP: 0018:ffffc900001f04a8 EFLAGS: 00000246 RAX: 1ffff110041ea229 RBX: 0000000000000000 RCX: ffff888024078000 RDX: 0000000000000100 RSI: 00007f35bdb9ce59 RDI: ffffffffa0004140 RBP: 0000000000000000 R08: dffffc0000000000 R09: 1ffffffff2238ea0 R10: dffffc0000000000 R11: fffffbfff2238ea1 R12: ffffffffa00040d8 R13: dffffc0000000000 R14: 00007f35bdb9ce59 R15: ffff888020f51368 FS: 00007f35be9c36c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000555584328a38 CR3: 00000000310cd000 CR4: 00000000003506e0 Call Trace: kernel_text_address+0xa0/0xd0 kernel/extable.c:125 __kernel_text_address+0xd/0x30 kernel/extable.c:79 unwind_get_return_address+0x5d/0xc0 arch/x86/kernel/unwind_orc.c:369 arch_stack_walk+0x11d/0x190 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:53 kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:237 kasan_slab_free include/linux/kasan.h:164 [inline] slab_free_hook mm/slub.c:1811 [inline] slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837 slab_free mm/slub.c:3830 [inline] kmem_cache_free+0xf8/0x270 mm/slub.c:3852 tcp_write_queue_purge+0x143/0x2f0 net/ipv4/tcp.c:3007 tcp_done_with_error+0x43/0xc0 net/ipv4/tcp_input.c:4446 tcp_write_err net/ipv4/tcp_timer.c:72 [inline] tcp_write_timeout net/ipv4/tcp_timer.c:281 [inline] tcp_retransmit_timer+0x1728/0x3020 net/ipv4/tcp_timer.c:576 tcp_write_timer+0x12a/0x280 net/ipv4/tcp_timer.c:709 call_timer_fn+0x189/0x540 kernel/time/timer.c:1701 expire_timers kernel/time/timer.c:1752 [inline] __run_timers+0x542/0x800 kernel/time/timer.c:2023 run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2036 handle_softirqs+0x280/0x820 kernel/softirq.c:578 __do_softirq kernel/softirq.c:612 [inline] invoke_softirq kernel/softirq.c:452 [inline] __irq_exit_rcu+0xd3/0x190 kernel/softirq.c:661 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline] sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:check_kcov_mode kernel/kcov.c:182 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x17/0x60 kernel/kcov.c:216 Code: 48 8b 3d 7c 0a 04 0d 48 89 de 5b e9 f3 6b 57 00 cc cc cc f3 0f 1e fa 48 8b 04 24 65 48 8b 0d 10 8e 7c 7e 65 8b 15 11 8e 7c 7e <81> e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 1c 16 00 00 RSP: 0018:ffffc90011f77700 EFLAGS: 00000283 RAX: ffffffff813b6e19 RBX: ffffc90011f77cb0 RCX: ffff888024078000 RDX: 0000000080000001 RSI: 0000000000015528 RDI: ffffc90011f77cb0 RBP: ffffc90011f77838 R08: ffff888024078000 R09: 0000000000000003 R10: 0000000000000004 R11: 0000000000000002 R12: ffffc90011f777e8 R13: dffffc0000000000 R14: ffffc90011f77cb0 R15: ffffffff8f1a05a6 __read_once_word_nocheck+0x9/0x10 include/asm-generic/rwonce.h:66 deref_stack_reg arch/x86/kernel/unwind_orc.c:406 [inline] unwind_next_frame+0x15f9/0x2970 arch/x86/kernel/unwind_orc.c:585 arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122 save_stack+0x125/0x230 mm/page_owner.c:128 __reset_page_owner+0x4e/0x190 mm/page_owner.c:149 reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1181 [inline] free_unref_page_prepare+0x7b2/0x8c0 mm/page_alloc.c:2365 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2458 discard_slab mm/slub.c:2127 [inline] __unfreeze_partials+0x1cf/0x210 mm/slub.c:2667 put_cpu_partial+0x17c/0x250 mm/slub.c:2743 __slab_free+0x319/0x400 mm/slub.c:3700 qlink_free mm/kasan/quarantine.c:166 [inline] qlist_free_all+0x75/0xd0 mm/kasan/quarantine.c:185 kasan_quarantine_reduce+0x143/0x160 mm/kasan/quarantine.c:292 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:306 kasan_slab_alloc include/linux/kasan.h:188 [inline] slab_post_alloc_hook+0x6e/0x4b0 mm/slab.h:767 slab_alloc_node mm/slub.c:3495 [inline] slab_alloc mm/slub.c:3503 [inline] __kmem_cache_alloc_lru mm/slub.c:3510 [inline] kmem_cache_alloc_lru+0x111/0x2d0 mm/slub.c:3526 alloc_inode_sb include/linux/fs.h:2946 [inline] sock_alloc_inode+0x28/0xc0 net/socket.c:308 alloc_inode fs/inode.c:261 [inline] new_inode_pseudo+0x63/0x1d0 fs/inode.c:1049 sock_alloc net/socket.c:634 [inline] __sock_create+0x12d/0x940 net/socket.c:1534 sock_create net/socket.c:1626 [inline] __sys_socketpair+0x1c1/0x550 net/socket.c:1777 __do_sys_socketpair net/socket.c:1830 [inline] __se_sys_socketpair net/socket.c:1827 [inline] __x64_sys_socketpair+0x9b/0xb0 net/socket.c:1827 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f35bdb9ce59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f35be9c3028 EFLAGS: 00000246 ORIG_RAX: 0000000000000035 RAX: ffffffffffffffda RBX: 00007f35bde15fa0 RCX: 00007f35bdb9ce59 RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000001 RBP: 00007f35bdc32d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000200000000040 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f35bde16038 R14: 00007f35bde15fa0 R15: 00007ffdbc44b588