> I don't want to defend the use of yield() but it looks like there is other > problem.
I believe this use of yield() should be replaced with cond_resched() even if it turns out there is an unrelated problem. > Does this module call netlink_broadcast() with __GFP_DIRECT_RECLAIM > in IRQ context? If so you should adjust the gfp flags. The module only calls netlink_broadcast() from a pluggable TCP function; from my understanding this is not in the IRQ context. Full trace, perhaps more clear, attached below. May 19 14:30:44 ccp kernel: [ 178.885546] BUG: scheduling while atomic: mm-link/3105/0x00000200 May 19 14:30:44 ccp kernel: [ 178.885552] Modules linked in: ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat libcrc32c xt_connmark nf_conntrack ccp(OE) crct10dif_pclmul crc32_pclmul ghash_clmulni_intel snd_intel8x0 pcbc snd_ac97_codec joydev ac97_bus snd_pcm snd_seq_midi snd_seq_midi_event snd_rawmidi aesni_intel snd_seq aes_x86_64 crypto_simd snd_seq_device snd_timer snd input_leds i2c_piix4 glue_helper cryptd so undcore mac_hid serio_raw vboxvideo ttm drm_kms_helper drm fb_sys_fops syscopyarea sysfillrect sysimgblt vboxguest intel_rapl_perf parport_pc ppdev lp parport ip_tables x_tables autofs4 hid_generic usbhid hid e1000 ahci libahci psmouse fjes pata_acpi video May 19 14:30:44 ccp kernel: [ 178.885665] CPU: 0 PID: 3105 Comm: mm-link Tainted: G W OE 4.10.0-21-generic #23-Ubuntu May 19 14:30:44 ccp kernel: [ 178.885666] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 May 19 14:30:44 ccp kernel: [ 178.885667] Call Trace: May 19 14:30:44 ccp kernel: [ 178.885674] dump_stack+0x63/0x81 May 19 14:30:44 ccp kernel: [ 178.885678] __schedule_bug+0x54/0x70 May 19 14:30:44 ccp kernel: [ 178.885682] __schedule+0x536/0x6f0 May 19 14:30:44 ccp kernel: [ 178.885685] schedule+0x36/0x80 May 19 14:30:44 ccp kernel: [ 178.885687] sys_sched_yield+0x4f/0x60 May 19 14:30:44 ccp kernel: [ 178.885688] yield+0x33/0x40 May 19 14:30:44 ccp kernel: [ 178.885691] netlink_broadcast_filtered+0x29b/0x3c0 May 19 14:30:44 ccp kernel: [ 178.885692] netlink_broadcast+0x1d/0x20 May 19 14:30:44 ccp kernel: [ 178.885697] nl_sendmsg+0xb8/0x664 [ccp] May 19 14:30:44 ccp kernel: [ 178.885699] nl_send_ack_notif+0x7d/0x90 [ccp] May 19 14:30:44 ccp kernel: [ 178.885702] tcp_ccp_cong_avoid+0x69/0x70 [ccp] May 19 14:30:44 ccp kernel: [ 178.885704] tcp_ack+0x980/0xa60 May 19 14:30:44 ccp kernel: [ 178.885708] tcp_rcv_state_process+0x2be/0xda0 May 19 14:30:44 ccp kernel: [ 178.885712] ? security_sock_rcv_skb+0x3b/0x50 May 19 14:30:44 ccp kernel: [ 178.885715] ? sk_filter_trim_cap+0x3b/0x270 May 19 14:30:44 ccp kernel: [ 178.885717] tcp_v4_do_rcv+0xb2/0x200 May 19 14:30:44 ccp kernel: [ 178.885719] tcp_v4_rcv+0x90a/0xa00 May 19 14:30:44 ccp kernel: [ 178.885722] ip_local_deliver_finish+0x96/0x1c0 May 19 14:30:44 ccp kernel: [ 178.885725] ip_local_deliver+0x6f/0xe0 May 19 14:30:44 ccp kernel: [ 178.885727] ? ip_rcv_finish+0x3f0/0x3f0 May 19 14:30:44 ccp kernel: [ 178.885730] ip_rcv_finish+0x118/0x3f0 May 19 14:30:44 ccp kernel: [ 178.885732] ip_rcv+0x282/0x390 May 19 14:30:44 ccp kernel: [ 178.885735] ? inet_del_offload+0x40/0x40 May 19 14:30:44 ccp kernel: [ 178.885737] __netif_receive_skb_core+0x514/0xa40 May 19 14:30:44 ccp kernel: [ 178.885740] ? __check_object_size+0x10/0x1d7 May 19 14:30:44 ccp kernel: [ 178.885742] __netif_receive_skb+0x18/0x60 May 19 14:30:44 ccp kernel: [ 178.885744] netif_receive_skb_internal+0x32/0xa0 May 19 14:30:44 ccp kernel: [ 178.885746] netif_receive_skb+0x1c/0x70 May 19 14:30:44 ccp kernel: [ 178.885749] tun_get_user+0x425/0x800 May 19 14:30:44 ccp kernel: [ 178.885751] tun_chr_write_iter+0x57/0x70 May 19 14:30:44 ccp kernel: [ 178.885752] new_sync_write+0xd5/0x130 May 19 14:30:44 ccp kernel: [ 178.885754] __vfs_write+0x26/0x40 May 19 14:30:44 ccp kernel: [ 178.885756] vfs_write+0xb5/0x1a0 May 19 14:30:44 ccp kernel: [ 178.885757] SyS_write+0x55/0xc0 May 19 14:30:44 ccp kernel: [ 178.885760] entry_SYSCALL_64_fastpath+0x1e/0xad May 19 14:30:44 ccp kernel: [ 178.885762] RIP: 0033:0x7f8d9abbf670 May 19 14:30:44 ccp kernel: [ 178.885763] RSP: 002b:00007ffc2f16d8b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 May 19 14:30:44 ccp kernel: [ 178.885765] RAX: ffffffffffffffda RBX: 00007ffc2f16dde0 RCX: 00007f8d9abbf670 May 19 14:30:44 ccp kernel: [ 178.885767] RDX: 0000000000000038 RSI: 0000557403fd86e0 RDI: 0000000000000008 May 19 14:30:44 ccp kernel: [ 178.885768] RBP: 00007ffc2f16dcd0 R08: 0000557403fd8d40 R09: 0000557403fd8690 May 19 14:30:44 ccp kernel: [ 178.885769] R10: 000e20d41e89a5c5 R11: 0000000000000246 R12: 0000000000000108 May 19 14:30:44 ccp kernel: [ 178.885770] R13: 000000000000145c R14: 00007ffc2f16dd98 R15: 0000000000000003
