Re: Regression in TTM driver w/Linus' master

[Adam Williamson <awilliam@redhat.com>]

On Wed, 2017-11-22 at 17:17 -0800, Laura Abbott wrote:
> Hi,
> 
> Fedora QA testing reported a panic when booting up VMs
> using qmeu vga drivers (https://paste.fedoraproject.org/paste/498yRWTCJv2LKIrmj4EliQ)
> 
> [   30.108507] ------------[ cut here ]------------
> [   30.108920] kernel BUG at ./include/linux/gfp.h:408!
> [   30.109356] invalid opcode: 0000 [#1] SMP
> [   30.109700] Modules linked in: fuse nf_conntrack_netbios_ns nf_conntrack_broadcast xt_CT ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 xt_conntrack devlink ip_set nfnetlink ebtable_nat ebtable_broute bridge ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle ip6table_raw ip6table_security iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack libcrc32c iptable_mangle iptable_raw iptable_security ebtable_filter ebtables ip6table_filter ip6_tables snd_hda_codec_generic kvm_intel kvm snd_hda_intel snd_hda_codec irqbypass ppdev snd_hda_core snd_hwdep snd_seq snd_seq_device snd_pcm bochs_drm ttm joydev drm_kms_helper virtio_balloon snd_timer snd parport_pc drm soundcore parport i2c_piix4 nls_utf8 isofs squashfs zstd_decompress xxhash 8021q garp mrp stp llc virtio_net
> [   30.115605]  virtio_console virtio_scsi crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel serio_raw virtio_pci virtio_ring virtio ata_generic pata_acpi qemu_fw_cfg sunrpc scsi_transport_iscsi loop
> [   30.117425] CPU: 0 PID: 1347 Comm: gnome-shell Not tainted 4.15.0-0.rc0.git6.1.fc28.x86_64 #1
> [   30.118141] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-2.fc27 04/01/2014
> [   30.118866] task: ffff923a77e03380 task.stack: ffffa78182228000
> [   30.119366] RIP: 0010:__alloc_pages_nodemask+0x35e/0x430
> [   30.119810] RSP: 0000:ffffa7818222bba8 EFLAGS: 00010202
> [   30.120250] RAX: 0000000000000001 RBX: 00000000014382c6 RCX: 0000000000000006
> [   30.120840] RDX: 0000000000000000 RSI: 0000000000000009 RDI: 0000000000000000
> [   30.121443] RBP: ffff923a760d6000 R08: 0000000000000000 R09: 0000000000000006
> [   30.122039] R10: 0000000000000040 R11: 0000000000000300 R12: ffff923a729273c0
> [   30.122629] R13: 0000000000000000 R14: 0000000000000000 R15: ffff923a7483d400
> [   30.123223] FS:  00007fe48da7dac0(0000) GS:ffff923a7cc00000(0000) knlGS:0000000000000000
> [   30.123896] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [   30.124373] CR2: 00007fe457b73000 CR3: 0000000078313000 CR4: 00000000000006f0
> [   30.124968] Call Trace:
> [   30.125186]  ttm_pool_populate+0x19b/0x400 [ttm]
> [   30.125578]  ttm_bo_vm_fault+0x325/0x570 [ttm]
> [   30.125964]  __do_fault+0x19/0x11e
> [   30.126255]  __handle_mm_fault+0xcd3/0x1260
> [   30.126609]  handle_mm_fault+0x14c/0x310
> [   30.126947]  __do_page_fault+0x28c/0x530
> [   30.127282]  do_page_fault+0x32/0x270
> [   30.127593]  async_page_fault+0x22/0x30
> [   30.127922] RIP: 0033:0x7fe48aae39a8
> [   30.128225] RSP: 002b:00007ffc21c4d928 EFLAGS: 00010206
> [   30.128664] RAX: 00007fe457b73000 RBX: 000055cd4c1041a0 RCX: 00007fe457b73040
> [   30.129259] RDX: 0000000000300000 RSI: 0000000000000000 RDI: 00007fe457b73000
> [   30.129855] RBP: 0000000000000300 R08: 000000000000000c R09: 0000000100000000
> [   30.130457] R10: 0000000000000001 R11: 0000000000000246 R12: 000055cd4c1041a0
> [   30.131054] R13: 000055cd4bdfe990 R14: 000055cd4c104110 R15: 0000000000000400
> [   30.131648] Code: 11 01 00 0f 84 a9 00 00 00 65 ff 0d 6d cc dd 44 e9 0f ff ff ff 40 80 cd 80 e9 99 fe ff ff 48 89 c7 e8 e7 f6 01 00 e9 b7 fe ff ff <0f> 0b 0f ff e9 40 fd ff ff 65 48 8b 04 25 80 d5 00 00 8b 40 4c
> [   30.133245] RIP: __alloc_pages_nodemask+0x35e/0x430 RSP: ffffa7818222bba8
> [   30.133836] ---[ end trace d4f1deb60784f40a ]---
> 
> This is based off of Linus' master branch at c8a0739b185d11d6e2ca7ad9f5835841d1cfc765
> Configs are at https://git.kernel.org/pub/scm/linux/kernel/git/jwboyer/fedora.git/commit/?h=rawhide&id=0be14662c54f49b4e640868b9d67df18d39edff0

To be as precise as I can at present, this appeared somewhere between
these two Fedora kernel package builds:

Package:      kernel-4.15.0-0.rc0.git6.1.fc28
Old package:  kernel-4.15.0-0.rc0.git3.1.fc28

(that is, 'git3' did not have the issue, 'git6' does). Laura could
translate that to a delta that'd mean more to you folks, I expect.
-- 
Adam Williamson
Fedora QA Community Monkey
IRC: adamw | Twitter: AdamW_Fedora | XMPP: adamw AT happyassassin . net
http://www.happyassassin.net