Comment 8 for bug 1821564

@Hans P Möller, i've tested with kernel 5.1.0-050100rc3-generic and the b44 module loaded and worked fine, but it created some others warnings in the dmesg:

[ 44.045886] b44 0000:02:09.0: swiotlb buffer is full (sz: 1566 bytes)
[ 44.045906] WARNING: CPU: 1 PID: 565 at kernel/dma/direct.c:43 report_addr+0x37/0x60
[ 44.045908] Modules linked in: snd_hda_codec_analog snd_hda_codec_generic ledtrig_audio snd_hda_intel snd_hda_codec snd_hda_core snd_hwdep r8188eu(C) snd_pcm snd_seq_midi snd_seq_midi_event lib80211 radeon cfg80211 snd_rawmidi joydev input_leds dcdbas coretemp ttm drm_kms_helper snd_seq drm i2c_algo_bit fb_sys_fops syscopyarea sysfillrect serio_raw snd_seq_device sysimgblt snd_timer snd soundcore mac_hid sch_fq_codel parport_pc ppdev lp parport ip_tables x_tables autofs4 pata_acpi hid_generic usbhid hid psmouse b44 ssb mii pata_atiixp i2c_piix4 ahci libahci
[ 44.045940] CPU: 1 PID: 565 Comm: NetworkManager Tainted: G WC 5.1.0-050100rc3-generic #201904010618
[ 44.045942] Hardware name: Dell Inc. OptiPlex 320 /0UT237, BIOS 1.1.12 06/17/2009
[ 44.045944] RIP: 0010:report_addr+0x37/0x60
[ 44.045946] Code: 48 8b 87 30 02 00 00 48 89 75 f8 48 85 c0 74 2a 4c 8b 00 b8 fe ff ff ff 49 39 c0 76 11 80 3d f7 6b 72 01 00 0f 84 cf 07 00 00 <0f> 0b c9 c3 48 83 bf 40 02 00 00 00 74 f2 eb e3 80 3d db 6b 72 01
[ 44.045947] RSP: 0018:ffff9fb4808af478 EFLAGS: 00010246
[ 44.045949] RAX: 00000000fffffffe RBX: ffff88a93bc1f0b0 RCX: 0000000000000000
[ 44.045950] RDX: 000000000000061e RSI: 000000007a2df880 RDI: ffff88a93bc1f0b0
[ 44.045951] RBP: ffff9fb4808af480 R08: 000000003fffffff R09: 0000000000000004
[ 44.045952] R10: 0000000000000000 R11: 0000000000000001 R12: 000000000000061e
[ 44.045953] R13: ffff88a92cc35500 R14: 0000000000000000 R15: ffff88a93c2898c0
[ 44.045955] FS: 00007fd85987abc0(0000) GS:ffff88a93fc40000(0000) knlGS:0000000000000000
[ 44.045956] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 44.045957] CR2: 00007f0e4401e008 CR3: 0000000033e44000 CR4: 00000000000006e0
[ 44.045958] Call Trace:
[ 44.045964] dma_direct_map_page+0xdf/0xf0
[ 44.045971] b44_alloc_rx_skb+0x18e/0x3f0 [b44]
[ 44.045973] b44_init_rings+0xbe/0x1b0 [b44]
[ 44.045976] b44_open+0xfc/0x3f0 [b44]
[ 44.045980] __dev_open+0xd4/0x170
[ 44.045982] __dev_change_flags+0x18f/0x200
[ 44.045984] dev_change_flags+0x27/0x60
[ 44.045986] do_setlink+0x32c/0xe30
[ 44.045991] ? __nla_parse+0xf1/0x120
[ 44.045995] ? cpumask_next+0x1b/0x20
[ 44.045998] ? __snmp6_fill_stats64.isra.57+0xf6/0x120
[ 44.046000] ? __nla_parse+0x38/0x120
[ 44.046002] __rtnl_newlink+0x52a/0x8f0
[ 44.046004] ? __nla_put+0x20/0x30
[ 44.046007] ? __kmalloc_node_track_caller+0x1db/0x2b0
[ 44.046009] ? pskb_expand_head+0x70/0x2e0
[ 44.046011] ? __kmalloc_reserve.isra.53+0x31/0x90
[ 44.046014] ? apparmor_inet_conn_request+0x40/0x40
[ 44.046017] ? security_sock_rcv_skb+0x2f/0x50
[ 44.046019] ? sk_filter_trim_cap+0x48/0x210
[ 44.046020] ? skb_queue_tail+0x43/0x50
[ 44.046024] ? __netlink_sendskb+0x53/0x70
[ 44.046029] ? fib6_clean_node+0x40/0x180
[ 44.046032] ? _cond_resched+0x19/0x30
[ 44.046034] ? kmem_cache_alloc_trace+0x150/0x1d0
[ 44.046036] rtnl_newlink+0x48/0x70
[ 44.046037] rtnetlink_rcv_msg+0x213/0x300
[ 44.046039] ? rtnl_calcit.isra.32+0x100/0x100
[ 44.046041] netlink_rcv_skb+0x4f/0x120
[ 44.046042] rtnetlink_rcv+0x15/0x20
[ 44.046044] netlink_unicast+0x19f/0x260
[ 44.046046] netlink_sendmsg+0x20d/0x3c0
[ 44.046048] sock_sendmsg+0x3e/0x50
[ 44.046050] ___sys_sendmsg+0x295/0x2f0
[ 44.046053] ? rtnl_unlock+0xe/0x10
[ 44.046055] ? addrconf_sysctl_forward+0x114/0x280
[ 44.046057] ? security_capable+0x3f/0x60
[ 44.046059] ? dev_forward_change+0x140/0x140
[ 44.046062] ? lockref_put_or_lock+0x60/0x80
[ 44.046064] ? __fget_light+0x59/0x70
[ 44.046066] __sys_sendmsg+0x5c/0xa0
[ 44.046068] __x64_sys_sendmsg+0x1f/0x30
[ 44.046071] do_syscall_64+0x5a/0x110
[ 44.046074] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 44.046076] RIP: 0033:0x7fd85b000cb7
[ 44.046078] Code: 44 00 00 41 54 41 89 d4 55 48 89 f5 53 89 fb 48 83 ec 10 e8 3b ed ff ff 44 89 e2 48 89 ee 89 df 41 89 c0 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 44 89 c7 48 89 44 24 08 e8 74 ed ff ff 48
[ 44.046079] RSP: 002b:00007ffc8d8acb80 EFLAGS: 00000293 ORIG_RAX: 000000000000002e
[ 44.046081] RAX: ffffffffffffffda RBX: 000000000000000a RCX: 00007fd85b000cb7
[ 44.046082] RDX: 0000000000000000 RSI: 00007ffc8d8acbd0 RDI: 000000000000000a
[ 44.046083] RBP: 00007ffc8d8acbd0 R08: 0000000000000000 R09: 0000000000000000
[ 44.046084] R10: 00007fd85afe6ca0 R11: 0000000000000293 R12: 0000000000000000
[ 44.046085] R13: 0000000000000000 R14: 00007ffc8d8acd88 R15: 00007ffc8d8acd7c
[ 44.046087] ---[ end trace 470ecf714c2b853b ]---
[ 44.046098] b44 0000:02:09.0: swiotlb buffer is full (sz: 1566 bytes)
[ 44.046102] b44 0000:02:09.0: swiotlb buffer is full (sz: 1566 bytes)
[ 44.046106] b44 0000:02:09.0: swiotlb buffer is full (sz: 1566 bytes)
[ 44.046110] b44 0000:02:09.0: swiotlb buffer is full (sz: 1566 bytes)
[ 44.046114] b44 0000:02:09.0: swiotlb buffer is full (sz: 1566 bytes)
[ 44.046118] b44 0000:02:09.0: swiotlb buffer is full (sz: 1566 bytes)
[ 44.046121] b44 0000:02:09.0: swiotlb buffer is full (sz: 1566 bytes)
[ 44.046125] b44 0000:02:09.0: swiotlb buffer is full (sz: 1566 bytes)
[ 44.046129] b44 0000:02:09.0: swiotlb buffer is full (sz: 1566 bytes)

Next, i'll try to bisect to find the bad commit.