============================= WARNING: suspicious RCU usage 5.3.0+ #0 Not tainted ----------------------------- include/net/sch_generic.h:492 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 4 locks held by net.agent/28567: #0: ffff888086add310 (&sig->cred_guard_mutex){+.+.}, at: prepare_bprm_creds fs/exec.c:1408 [inline] #0: ffff888086add310 (&sig->cred_guard_mutex){+.+.}, at: __do_execve_file.isra.0+0x376/0x2340 fs/exec.c:1753 #1: ffff8880ae809d50 ((&n->timer)){+.-.}, at: lockdep_copy_map include/linux/lockdep.h:172 [inline] #1: ffff8880ae809d50 ((&n->timer)){+.-.}, at: call_timer_fn+0xe0/0x780 kernel/time/timer.c:1394 #2: ffffffff88fab240 (rcu_read_lock_bh){....}, at: __dev_queue_xmit+0x20a/0x35b0 net/core/dev.c:3808 #3: ffff888069fd6540 (&(&sch->q.lock)->rlock){+.-.}, at: spin_lock include/linux/spinlock.h:338 [inline] #3: ffff888069fd6540 (&(&sch->q.lock)->rlock){+.-.}, at: __dev_xmit_skb net/core/dev.c:3506 [inline] #3: ffff888069fd6540 (&(&sch->q.lock)->rlock){+.-.}, at: __dev_queue_xmit+0x14b0/0x35b0 net/core/dev.c:3842 stack backtrace: CPU: 0 PID: 28567 Comm: net.agent Not tainted 5.3.0+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 lockdep_rcu_suspicious+0x153/0x15d kernel/locking/lockdep.c:5438 qdisc_root include/net/sch_generic.h:492 [inline] netem_enqueue+0x1cfb/0x2d80 net/sched/sch_netem.c:479 __dev_xmit_skb net/core/dev.c:3531 [inline] __dev_queue_xmit+0x157e/0x35b0 net/core/dev.c:3842 dev_queue_xmit+0x18/0x20 net/core/dev.c:3906 arp_xmit_finish net/ipv4/arp.c:630 [inline] NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] arp_xmit+0xdf/0x3f0 net/ipv4/arp.c:639 arp_send_dst.part.0+0x202/0x280 net/ipv4/arp.c:317 arp_send_dst net/ipv4/arp.c:390 [inline] arp_solicit+0x752/0x1380 net/ipv4/arp.c:389 neigh_probe+0xc6/0x110 net/core/neighbour.c:1012 neigh_timer_handler+0x59d/0xf60 net/core/neighbour.c:1093 call_timer_fn+0x1ac/0x780 kernel/time/timer.c:1404 expire_timers kernel/time/timer.c:1449 [inline] __run_timers kernel/time/timer.c:1771 [inline] __run_timers kernel/time/timer.c:1738 [inline] run_timer_softirq+0x6c0/0x17f0 kernel/time/timer.c:1784 __do_softirq+0x262/0x98c kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x19b/0x1e0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1137 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830 RIP: 0010:__read_once_size include/linux/compiler.h:199 [inline] RIP: 0010:is_huge_zero_page include/linux/huge_mm.h:247 [inline] RIP: 0010:release_pages+0xfc/0x1a50 mm/swap.c:740 Code: fc ff df 48 c1 e8 03 4c 89 a5 60 ff ff ff 41 89 cc 4c 01 f8 48 89 85 58 ff ff ff e8 fe ee df ff 48 8b 85 58 ff ff ff 80 38 00 <0f> 85 e3 14 00 00 48 8b 05 cf e9 33 08 49 39 c6 0f 84 11 04 00 00 RSP: 0018:ffff888055fe7828 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: fffffbfff138d147 RBX: 00000000000000cf RCX: ffffffff8192a49c RDX: 0000000000000000 RSI: ffffffff8192a052 RDI: 0000000000000004 RBP: ffff888055fe7908 R08: ffff8880665b03c0 R09: fffff9400005c3cf R10: fffff9400005c3ce R11: ffffea00002e1e77 R12: 000000000000000c R13: 0000000000000027 R14: ffffea00002e1e80 R15: dffffc0000000000 free_pages_and_swap_cache+0x2c3/0x3f0 mm/swap_state.c:296 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline] tlb_flush_mmu_free mm/mmu_gather.c:184 [inline] tlb_flush_mmu+0x89/0x630 mm/mmu_gather.c:191 tlb_finish_mmu+0x98/0x3b0 mm/mmu_gather.c:272 exit_mmap+0x2da/0x530 mm/mmap.c:3151 __mmput kernel/fork.c:1066 [inline] mmput+0x179/0x4d0 kernel/fork.c:1087 exec_mmap fs/exec.c:1047 [inline] flush_old_exec+0x8c4/0x1da0 fs/exec.c:1280 load_elf_binary+0xa64/0x5730 fs/binfmt_elf.c:867 search_binary_handler fs/exec.c:1658 [inline] search_binary_handler+0x16d/0x570 fs/exec.c:1635 exec_binprm fs/exec.c:1701 [inline] __do_execve_file.isra.0+0x1333/0x2340 fs/exec.c:1821 do_execveat_common fs/exec.c:1868 [inline] do_execve fs/exec.c:1885 [inline] __do_sys_execve fs/exec.c:1961 [inline] __se_sys_execve fs/exec.c:1956 [inline] __x64_sys_execve+0x8f/0xc0 fs/exec.c:1956 do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f9bd55ce207 Code: Bad RIP value. RSP: 002b:00007ffdd1755328 EFLAGS: 00000206 ORIG_RAX: 000000000000003b RAX: ffffffffffffffda RBX: 000000000226c620 RCX: 00007f9bd55ce207 RDX: 000000000226c658 RSI: 000000000226c620 RDI: 000000000226c6b0 RBP: 000000000226c6b0 R08: 000000000226c5d0 R09: 00007f9bd5645800 R10: 0000000000000000 R11: 0000000000000206 R12: 000000000226c658 R13: 000000000226c658 R14: 0000000000000000 R15: 0000000000000000