rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (2 GPs behind) idle=1f8c/1/0x4000000000000000 softirq=17782/17782 fqs=2 rcu: (detected by 1, t=10502 jiffies, g=11385, q=303 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5980 Comm: syz-executor Not tainted 6.16.0-rc7-syzkaller-00091-geccf7a3480a0 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:rcu_read_unlock include/linux/rcupdate.h:869 [inline] RIP: 0010:advance_sched+0xa9f/0xc90 net/sched/sch_taprio.c:987 Code: 68 3d fe 05 01 48 c7 c7 60 1b 97 8c be 4b 03 00 00 48 c7 c2 a0 1b 97 8c e8 ce f2 10 f8 4c 89 ef e8 26 30 c7 ff e8 21 3d e0 01 <89> c5 31 ff 89 c6 e8 46 b8 32 f8 85 ed 74 10 e8 bd b8 19 f8 84 c0 RSP: 0018:ffffc90000007c70 EFLAGS: 00000046 RAX: 0000000000000001 RBX: ffffffff898d7218 RCX: ffff888026109e00 RDX: 0000000000010000 RSI: 0000000000000001 RDI: 0000000000000002 RBP: 0000000000000001 R08: ffff888034af415f R09: 1ffff1100695e82b R10: dffffc0000000000 R11: ffffed100695e82c R12: ffff888034af4360 R13: ffff888034af4000 R14: 1855e3874c17cef4 R15: ffff88807480a000 FS: 0000555558dc0500(0000) GS:ffff888125c23000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000600 CR3: 0000000033310000 CR4: 00000000003526f0 Call Trace: __run_hrtimer kernel/time/hrtimer.c:1761 [inline] __hrtimer_run_queues+0x52c/0xc60 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline] __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1056 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 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 2e 25 49 0c 8d 42 ff 44 39 f8 0f 86 65 18 00 00 44 89 f8 4c 8d 2c 85 d4 da dd 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:ffffc900043df338 EFLAGS: 00000a02 RAX: 0000000000000000 RBX: 0000000000000001 RCX: 701681295f8d5700 RDX: 00000000000a716d RSI: ffffffff8be28d20 RDI: ffffffff8be28ce0 RBP: dffffc0000000000 R08: 0000000000000000 R09: ffffffff8172aae5 R10: ffffc900043df458 R11: ffffffff81acfe40 R12: ffffffff8993bb53 R13: ffffffff910029c0 R14: ffffc900043df408 R15: 00000000000893bb 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 unpoison_slab_object mm/kasan/common.c:319 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:345 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4148 [inline] slab_alloc_node mm/slub.c:4197 [inline] kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4204 skb_clone+0x212/0x3a0 net/core/skbuff.c:2050 __netlink_deliver_tap_skb net/netlink/af_netlink.c:300 [inline] __netlink_deliver_tap+0x404/0x850 net/netlink/af_netlink.c:325 netlink_deliver_tap+0x19c/0x1b0 net/netlink/af_netlink.c:338 __netlink_sendskb net/netlink/af_netlink.c:1262 [inline] netlink_sendskb+0x68/0x140 net/netlink/af_netlink.c:1271 netlink_rcv_skb+0x28c/0x470 net/netlink/af_netlink.c:2558 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x75c/0x8e0 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:727 __sys_sendto+0x3bd/0x520 net/socket.c:2180 __do_sys_sendto net/socket.c:2187 [inline] __se_sys_sendto net/socket.c:2183 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2183 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: 0033:0x7f49c499083c Code: 2a 5f 02 00 44 8b 4c 24 2c 4c 8b 44 24 20 89 c5 44 8b 54 24 28 48 8b 54 24 18 b8 2c 00 00 00 48 8b 74 24 10 8b 7c 24 08 0f 05 <48> 3d 00 f0 ff ff 77 34 89 ef 48 89 44 24 08 e8 70 5f 02 00 48 8b RSP: 002b:00007ffcf9f7c350 EFLAGS: 00000293 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f49c56e4620 RCX: 00007f49c499083c RDX: 0000000000000028 RSI: 00007f49c56e4670 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007ffcf9f7c3a4 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003 R13: 0000000000000000 R14: 00007f49c56e4670 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10498 jiffies! g11385 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:27128 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5397 [inline] __schedule+0x16fd/0x4cf0 kernel/sched/core.c:6786 __schedule_loop kernel/sched/core.c:6864 [inline] schedule+0x165/0x360 kernel/sched/core.c:6879 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2054 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2256 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 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: 5976 Comm: syz-executor Not tainted 6.16.0-rc7-syzkaller-00091-geccf7a3480a0 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0xf7b/0x12d0 kernel/smp.c:885 Code: 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 3b 6a 0b 00 eb 37 f3 90 43 0f b6 04 2c 84 c0 75 10 41 f7 07 01 00 00 00 74 1e 20 6a 0b 00 eb e5 44 89 f9 80 e1 07 80 c1 03 38 c1 7c e3 4c 89 RSP: 0000:ffffc90003c4f720 EFLAGS: 00000202 RAX: 0000000000000000 RBX: ffff8880b873b1c0 RCX: ffff8880260e0000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90003c4f880 R08: ffffffff8fa1def7 R09: 1ffffffff1f43bde R10: dffffc0000000000 R11: fffffbfff1f43bdf R12: 1ffff110170c8385 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8880b8641c28 FS: 0000555572c57500(0000) GS:ffff888125d23000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f868bf83ef8 CR3: 0000000028b46000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1052 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline] flush_tlb_mm_range+0x6b1/0x12c0 arch/x86/mm/tlb.c:1451 flush_tlb_page arch/x86/include/asm/tlbflush.h:324 [inline] ptep_clear_flush+0x120/0x170 mm/pgtable-generic.c:101 wp_page_copy mm/memory.c:3635 [inline] do_wp_page+0x1bc2/0x5800 mm/memory.c:4030 handle_pte_fault mm/memory.c:6085 [inline] __handle_mm_fault+0x1144/0x5620 mm/memory.c:6212 handle_mm_fault+0x40a/0x8e0 mm/memory.c:6381 do_user_addr_fault+0xa81/0x1390 arch/x86/mm/fault.c:1336 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: 0033:0x7f868bc52ee7 Code: 00 e8 9d 63 ff ff 85 c0 74 54 49 8b 34 24 8b 54 24 0c 31 c0 48 8d 3d ed e7 1b 00 e8 43 b1 ff ff 8b 44 24 6c 8b 74 24 08 89 ef <49> 89 9c 24 b8 00 00 00 49 8d 4c 24 60 ba 40 00 00 00 41 89 84 24 RSP: 002b:00007ffe3ba7f900 EFLAGS: 00010202 RAX: 0000000000000004 RBX: 00007ffe3ba7f980 RCX: 0000000000000002 RDX: 0000000000000002 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 0000000000000003 R08: 00007ffe3ba7f91c R09: 00007ffe3ba7fd37 R10: 00007ffe3ba7f980 R11: 0000000000000216 R12: 00007f868bf83e40 R13: 00007ffe3ba7f91c R14: 0000000000000000 R15: 00007f868bf86000