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rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4928/1:b..l (detected by 0, t=10502 jiffies, g=13845, q=229 ncpus=2) task:syz.2.158 state:R running task stack:22808 pid:4928 ppid:4274 flags:0x00004002 Call Trace: <TASK> context_switch kernel/sched/core.c:5245 [inline] __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6731 preempt_schedule+0xbc/0xd0 kernel/sched/core.c:6755 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34 __local_bh_enable_ip+0x147/0x1c0 kernel/softirq.c:428 local_bh_enable include/linux/bottom_half.h:33 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:861 [inline] __dev_queue_xmit+0x1cd2/0x37c0 net/core/dev.c:4411 dev_queue_xmit include/linux/netdevice.h:3051 [inline] __bpf_tx_skb net/core/filter.c:2134 [inline] __bpf_redirect_common net/core/filter.c:2182 [inline] __bpf_redirect+0xbdf/0x1180 net/core/filter.c:2189 ____bpf_clone_redirect net/core/filter.c:2473 [inline] bpf_clone_redirect+0x30b/0x4a0 net/core/filter.c:2436 bpf_prog_c6f54bbad6dab1ee+0x56/0x5b bpf_dispatcher_nop_func include/linux/bpf.h:1012 [inline] __bpf_prog_run include/linux/filter.h:607 [inline] bpf_prog_run include/linux/filter.h:614 [inline] bpf_test_run+0x2b6/0x830 net/bpf/test_run.c:402 bpf_prog_test_run_skb+0xaa6/0x12a0 net/bpf/test_run.c:1191 bpf_prog_test_run+0x31e/0x390 kernel/bpf/syscall.c:3695 __sys_bpf+0x62b/0x780 kernel/bpf/syscall.c:5049 __do_sys_bpf kernel/bpf/syscall.c:5135 [inline] __se_sys_bpf kernel/bpf/syscall.c:5133 [inline] __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:5133 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f5b5b99c819 RSP: 002b:00007f5b5c81a028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f5b5bc15fa0 RCX: 00007f5b5b99c819 RDX: 0000000000000050 RSI: 00002000000011c0 RDI: 000000000000000a RBP: 00007f5b5ba32c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f5b5bc16038 R14: 00007f5b5bc15fa0 R15: 00007ffee61fe3a8 </TASK> rcu: rcu_preempt kthread starved for 10313 jiffies! g13845 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:27184 pid:16 ppid:2 flags:0x00004000 Call Trace: <TASK> context_switch kernel/sched/core.c:5245 [inline] __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562 schedule+0xb9/0x180 kernel/sched/core.c:6638 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x303/0x1340 kernel/rcu/tree.c:1706 rcu_gp_kthread+0x99/0x3b0 kernel/rcu/tree.c:1905 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 </TASK> rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 4917 Comm: syz.1.155 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:mark_lock+0xe2/0x320 kernel/locking/lockdep.c:4606 Code: 03 42 0f b6 04 28 84 c0 0f 85 06 02 00 00 83 3d 03 09 5b 15 00 74 36 45 31 ff 49 83 c7 50 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 <74> 08 4c 89 ff e8 34 89 6e 00 b8 01 00 00 00 45 85 27 74 50 48 83 RSP: 0018:ffffc900001e02a0 EFLAGS: 00000046 RAX: 1ffffffff2090b12 RBX: ffff88802e591dc0 RCX: ffffffff8164f804 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff90af9248 RBP: 0000000000000000 R08: ffffffff90af924f R09: 1ffffffff215f249 R10: dffffc0000000000 R11: fffffbfff215f24a R12: 0000000000000001 R13: dffffc0000000000 R14: ffff88802e592918 R15: ffffffff90485890 FS: 00007fe9ee4376c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5b5c7d7ff8 CR3: 000000002eef1000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: <IRQ> mark_usage kernel/locking/lockdep.c:4520 [inline] __lock_acquire+0xc34/0x7d10 kernel/locking/lockdep.c:5003 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5662 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xb0/0x100 kernel/locking/spinlock.c:162 hrtimer_interrupt+0xf8/0x9c0 kernel/time/hrtimer.c:1854 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline] __sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0x4d/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:mac80211_hwsim_tx_frame_no_nl+0xe3e/0x12c0 drivers/net/wireless/mac80211_hwsim.c:1681 Code: 89 ef 48 8d b4 24 90 00 00 00 4c 89 fa e8 3a 19 ff ff 4c 8b 7c 24 10 66 41 c7 44 1c 0c f8 f8 4c 89 e8 48 c1 e8 03 80 3c 18 00 <74> 08 4c 89 ef e8 08 f0 d6 fb 4d 8b 6d 00 49 81 fd a0 d1 61 8d 0f RSP: 0018:ffffc900001e0940 EFLAGS: 00000246 RAX: 1ffff1100eeab664 RBX: dffffc0000000000 RCX: ffff88802e591dc0 RDX: 0000000000000100 RSI: 0000000000000004 RDI: 0000000000000003 RBP: ffffc900001e0ae0 R08: ffff88802e591dc0 R09: 0000000000000002 R10: 0000000000000003 R11: 0000000000000100 R12: 1ffff9200003c140 R13: ffff88807755b320 R14: 0000000000000004 R15: ffff8880286335b8 mac80211_hwsim_tx_frame+0x1b5/0x200 drivers/net/wireless/mac80211_hwsim.c:2058 mac80211_hwsim_beacon_tx+0x61e/0xae0 drivers/net/wireless/mac80211_hwsim.c:2121 __iterate_interfaces+0x243/0x500 net/mac80211/util.c:788 ieee80211_iterate_active_interfaces_atomic+0xd7/0x170 net/mac80211/util.c:824 mac80211_hwsim_beacon+0xb7/0x1b0 drivers/net/wireless/mac80211_hwsim.c:2147 __run_hrtimer kernel/time/hrtimer.c:1747 [inline] __hrtimer_run_queues+0x54a/0xd50 kernel/time/hrtimer.c:1811 hrtimer_run_softirq+0x183/0x2a0 kernel/time/hrtimer.c:1828 handle_softirqs+0x2a1/0x930 kernel/softirq.c:596 __do_softirq kernel/softirq.c:630 [inline] invoke_softirq kernel/softirq.c:470 [inline] __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:679 irq_exit_rcu+0x5/0x20 kernel/softirq.c:691 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118 </IRQ> <TASK> asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:preempt_schedule_irq+0xb6/0x160 kernel/sched/core.c:6874 Code: 00 00 43 c6 44 37 04 f8 74 0b 0f 0b 48 f7 03 08 00 00 00 74 7f bf 01 00 00 00 e8 15 54 22 f7 e8 10 48 52 f7 fb bf 01 00 00 00 <e8> 75 b9 ff ff 43 c6 44 37 08 00 48 c7 44 24 40 00 00 00 00 9c 8f RSP: 0018:ffffc9000cd676c0 EFLAGS: 00000282 RAX: 10afcc37190cd600 RBX: 0000000000000000 RCX: 10afcc37190cd600 RDX: dffffc0000000000 RSI: ffffffff8a8c10a0 RDI: 0000000000000001 RBP: ffffc9000cd67760 R08: ffff8880b8f3580b R09: 1ffff110171e6b01 R10: dffffc0000000000 R11: ffffed10171e6b02 R12: 0000000000000000 R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffff920019aced8 irqentry_exit+0x63/0x70 kernel/entry/common.c:439 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:qlink_to_object mm/kasan/quarantine.c:140 [inline] RIP: 0010:qlink_free mm/kasan/quarantine.c:145 [inline] RIP: 0010:qlist_free_all+0x40/0xe0 mm/kasan/quarantine.c:187 Code: 00 49 89 f6 48 89 fb 49 bd 00 00 00 00 00 fc ff df 49 89 ef 4d 89 f4 4d 85 f6 75 0b 4c 89 ff e8 66 03 00 00 49 89 c4 49 8b 2f <49> 63 84 24 c0 00 00 00 49 29 c7 4c 89 e7 4c 89 fe e8 5a ec ff ff RSP: 0018:ffffc9000cd67828 EFLAGS: 00000286 RAX: ffff888017441c80 RBX: ffffc9000cd67868 RCX: ffffea0001e75200 RDX: ffffea0000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff88801efe7780 R08: ffff88801efe78c0 R09: 00000000800c0005 R10: dffffc0000000000 R11: ffffed10171e6b02 R12: ffff888017441c80 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff888079d4b800 kasan_quarantine_reduce+0x144/0x160 mm/kasan/quarantine.c:294 __kasan_slab_alloc+0x1e/0x80 mm/kasan/common.c:306 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook+0x4b/0x480 mm/slab.h:737 slab_alloc_node mm/slub.c:3359 [inline] slab_alloc mm/slub.c:3367 [inline] __kmem_cache_alloc_lru mm/slub.c:3374 [inline] kmem_cache_alloc+0x123/0x2f0 mm/slub.c:3383 kmem_cache_zalloc include/linux/slab.h:689 [inline] taskstats_tgid_alloc kernel/taskstats.c:583 [inline] taskstats_exit+0x151/0x9d0 kernel/taskstats.c:622 do_exit+0x8f8/0x2480 kernel/exit.c:856 do_group_exit+0x217/0x2d0 kernel/exit.c:1022 get_signal+0x1272/0x1350 kernel/signal.c:2871 arch_do_signal_or_restart+0xc4/0x1350 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fe9ed59c819 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:00007fe9ee4370e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007fe9ed815fa8 RCX: 00007fe9ed59c819 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fe9ed815fa8 RBP: 00007fe9ed815fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe9ed816038 R14: 00007ffed2355540 R15: 00007ffed2355628 </TASK>
| Time | Kernel | Commit | Syzkaller | Config | Log | Report | Syz repro | C repro | VM info | Assets (help?) | Manager | Title |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2026/04/15 21:00 | linux-6.1.y | 8e8fc038cad5 | c441f497 | .config | console log | report | info | [disk image] [vmlinux] [kernel image] | ci2-linux-6-1-kasan-perf | INFO: rcu detected stall in mac80211_hwsim_beacon |