Kernel panic on a nfsroot system

[Sergey Kozlov]

== SRU Justification ==
The following commit introduced a regression identified in bug 1734327:
ac8f82a0b6d9 ("UBUNTU: SAUCE: LSM stacking: LSM: Infrastructure management of the remaining blobs")

The regression causes a kernel panic to occur after multiple TCP connection
creations/closures to the localhost. The bug was found using STAF RPC calls,
but is easily reproducible with SSH.

A revert of commit ac8f82a0b6d9 is needed to resolve this bug. However, commit 4ae2508f0bed
also needs to be reverted because it depend on commit ac8f82a0b6d9.

== Fix ==
Revert 4ae2508f0bed ("UBUNTU: SAUCE: LSM stacking: add stacking support to apparmor network hooks")
Revert ac8f82a0b6d9 ("UBUNTU: SAUCE: LSM stacking: LSM: Infrastructure management of the remaining blobs")

== Test Case ==
A test kernel was built with these two commits reverted and tested by the original bug reporter.
The bug reporter states the test kernel resolved the bug.

== Original Bug Description ==
Summary:
Kernel panic occurs after multiple TCP connection creations/closures to the localhost.
The bug was found using STAF RPC calls, but is easily reproducible with SSH.
The bug doesn't appear on an identical virtual machine booting from the disk.
The bug is not reproducible on a similarly-prepared Ubuntu 16.04 machine.
The bug is reproducible using an older 4.13.0-16-generic kernel
Reproducible on multiple hardware types.
Unable to create a kernel memory dump due to makedumpfile errors.
apport-bug save attached.

NFSRoot boot options:
vmlinuz initrd=initrd.img boot=nfs root=/dev/nfs nfsroot=190.0.0.254:/diskless/host/u1616/Ubuntu/17.10 intel_iommu=on net.ifnames=0 biosdevname=0 apparmor=0 ip=:::::eth0:dhcp blacklist=i40e,ixgbe,fm10k crashkernel=384M-:768M rw

Software:
OS: Ubuntu 17.10
Kernel: 4.13.0-17-generic x86_64

Reproduction steps:
1. Boot a system from a nfsroot
2. Configure password-less localhost ssh access
3. Run a loop: `while true; do ssh localhost 'uname -a'; done`
4. Wait for system to crash

Trace:
4,1151,52372730,-;general protection fault: 0000 [#1] SMP
4,1152,52372771,-;Modules linked in: arc4 md4 rpcsec_gss_krb5 nls_utf8 auth_rpcgss cifs nfsv4 ccm ipmi_ssif intel_rapl sb_edac x86_pkg_temp_thermal intel_powerclamp coretemp intel_cstate mei_me input_leds joydev intel_rapl_perf mei kvm_intel lpc_ich ioatdma kvm irqbypass ipmi_si ipmi_devintf ipmi_msghandler shpchp acpi_pad acpi_power_meter mac_hid ib_iser rdma_cm iw_cm ib_cm ib_core iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi ip_tables x_tables autofs4 nfsv3 nfs_acl nfs lockd grace sunrpc fscache raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor hid_generic usbhid hid raid6_pq libcrc32c raid1 raid0 multipath linear uas usb_storage crct10dif_pclmul crc32_pclmul ghash_clmulni_intel pcbc ast ttm aesni_intel igb drm_kms_helper aes_x86_64 crypto_simd syscopyarea glue_helper
4,1153,52373251,c; sysfillrect dca cryptd sysimgblt i2c_algo_bit fb_sys_fops ahci ptp drm libahci pps_core wmi
4,1154,52373322,-;CPU: 11 PID: 1848 Comm: STAFProc Not tainted 4.13.0-17-generic #20-Ubuntu
4,1155,52373371,-;Hardware name: Supermicro Super Server/X10SRD-F, BIOS 2.0 12/17/2015
4,1156,52373418,-;task: ffff9d09267f5d00 task.stack: ffffafddc3a70000
4,1157,52373461,-;RIP: 0010:kfree+0x53/0x160
4,1158,52373486,-;RSP: 0018:ffff9d092ecc3bc8 EFLAGS: 00010207
4,1159,52373521,-;RAX: 0000000000000000 RBX: 241c894900000001 RCX: 0000000000000004
4,1160,52373566,-;RDX: 000032d49081cc08 RSI: 0000000000010080 RDI: 000062fac0000000
4,1161,52373611,-;RBP: ffff9d092ecc3be0 R08: 000000000001f4c0 R09: ffffffff943bb839
4,1162,52373656,-;R10: 00904c7891000000 R11: 0000000000000000 R12: ffff9d09267ef000
4,1163,52373701,-;R13: ffffffff93fa155e R14: ffff9d09267ef000 R15: ffff9d09267ef000
4,1164,52373746,-;FS: 00007f3a53313700(0000) GS:ffff9d092ecc0000(0000) knlGS:0000000000000000
4,1165,52373797,-;CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
4,1166,52373834,-;CR2: 00007fd5c9ffa780 CR3: 00000004666d7000 CR4: 00000000003406e0
4,1167,52373878,-;DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
4,1168,52373923,-;DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
4,1169,52373968,-;Call Trace:
4,1170,52373987,-; <IRQ>
4,1171,52374009,-; security_sk_free+0x3e/0x50
4,1172,52374042,-; __sk_destruct+0x108/0x190
4,1173,52374070,-; sk_destruct+0x20/0x30
4,1174,52374095,-; __sk_free+0x82/0xa0
4,1175,52374120,-; sk_free+0x19/0x20
4,1176,52374144,-; sock_put+0x14/0x20
4,1177,52374168,-; tcp_v4_rcv+0x94d/0x9d0
4,1178,52374195,-; ip_local_deliver_finish+0x5c/0x1f0
4,1179,52374226,-; ip_local_deliver+0x6f/0xe0
4,1180,52374254,-; ip_rcv_finish+0x120/0x410
4,1181,52374281,-; ip_rcv+0x28c/0x3a0
4,1182,52374305,-; ? update_load_avg+0x46d/0x590
4,1183,52374335,-; __netif_receive_skb_core+0x39a/0xaa0
4,1184,52374369,-; __netif_receive_skb+0x18/0x60
4,1185,52374398,-; ? __netif_receive_skb+0x18/0x60
4,1186,52374428,-; process_backlog+0x89/0x140
4,1187,52374457,-; net_rx_action+0x13b/0x380
4,1188,52374485,-; __do_softirq+0xde/0x2a5
4,1189,52375837,-; do_softirq_own_stack+0x1c/0x30
4,1190,52377188,-; </IRQ>
4,1191,52378538,-; do_softirq.part.17+0x4e/0x50
4,1192,52379869,-; __local_bh_enable_ip+0x5a/0x60
4,1193,52381174,-; ip_finish_output2+0x172/0x3a0
4,1194,52382442,-; ip_finish_output+0x190/0x250
4,1195,52383658,-; ? ip_finish_output+0x190/0x250
4,1196,52384833,-; ip_output+0x70/0xe0
4,1197,52385959,-; ? lock_timer_base+0x81/0xa0
4,1198,52387043,-; ip_local_out+0x35/0x40
4,1199,52388078,-; ip_queue_xmit+0x160/0x3e0
4,1200,52389068,-; ? __alloc_skb+0x87/0x1e0
4,1201,52390019,-; tcp_transmit_skb+0x538/0x9e0
4,1202,52390944,-; tcp_send_ack.part.35+0xbd/0x130
4,1203,52391849,-; tcp_send_ack+0x16/0x20
4,1204,52392729,-; tcp_cleanup_rbuf+0x67/0x100
4,1205,52393600,-; tcp_recvmsg+0x572/0xb60
4,1206,52394464,-; inet_recvmsg+0x4b/0xc0
4,1207,52395307,-; sock_recvmsg+0x3d/0x50
4,1208,52396135,-; sock_read_iter+0x90/0xe0
4,1209,52396955,-; new_sync_read+0xde/0x130
4,1210,52397766,-; __vfs_read+0x26/0x40
4,1211,52398568,-; vfs_read+0x8e/0x130
4,1212,52399347,-; SyS_read+0x55/0xc0
4,1213,52400099,-; entry_SYSCALL_64_fastpath+0x1e/0xa9
4,1214,52400845,-;RIP: 0033:0x7f3a58da0d5d
4,1215,52401583,-;RSP: 002b:00007f3a53310e70 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
4,1216,52402370,-;RAX: ffffffffffffffda RBX: 00007f3a44000078 RCX: 00007f3a58da0d5d
4,1217,52403153,-;RDX: 0000000000000020 RSI: 00007f3a4400b5f8 RDI: 000000000000000f
4,1218,52403952,-;RBP: 0000000000001010 R08: 0000000000000000 R09: 0000000000000000
4,1219,52404752,-;R10: 00007f3a593e4d20 R11: 0000000000000246 R12: 00007f3a44000020
4,1220,52405553,-;R13: 0000000000001000 R14: 00007f3a44000078 R15: 0000000000000001
4,1221,52406363,-;Code: 00 80 49 01 da 0f 82 1c 01 00 00 48 c7 c7 00 00 00 80 48 2b 3d 7f e6 c1 00 49 01 fa 49 c1 ea 0c 49 c1 e2 06 4c 03 15 5d e6 c1 00 <49> 8b 42 20 48 8d 50 ff a8 01 4c 0f 45 d2 49 8b 52 20 48 8d 42
1,1222,52408171,-;RIP: kfree+0x53/0x160 RSP: ffff9d092ecc3bc8
4,1223,52409129,-;---[ end trace f7b53e7f81a1cbda ]---
0,1224,52414686,-;Kernel panic - not syncing: Fatal exception in interrupt
---
AlsaDevices:
 total 0
 crw-rw---- 1 root audio 116, 1 Nov 24 12:39 seq
 crw-rw---- 1 root audio 116, 33 Nov 24 12:39 timer
AplayDevices: Error: [Errno 2] No such file or directory
ApportVersion: 2.20.7-0ubuntu3.5
Architecture: amd64
ArecordDevices: Error: [Errno 2] No such file or directory
AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1:
DistroRelease: Ubuntu 17.10
InstallationDate: Installed on 2017-11-03 (21 days ago)
InstallationMedia: Ubuntu-Server 17.10 "Artful Aardvark" - Release amd64 (20171017.1)
IwConfig: Error: [Errno 2] No such file or directory
MachineType: Supermicro Super Server
Package: linux (not installed)
PciMultimedia:

ProcFB: 0 astdrmfb
ProcKernelCmdLine: vmlinuz initrd=initrd.img boot=nfs root=/dev/nfs nfsroot=190.0.0.254:/diskless/host/hostname/Ubuntu/17.10 intel_iommu=on net.ifnames=0 biosdevname=0 apparmor=0 ip=:::::eth0:dhcp blacklist=i40e,ixgbe,fm10k crashkernel=384M-:768M rw
ProcVersionSignature: Ubuntu 4.13.0-17.20-generic 4.13.8
RelatedPackageVersions:
 linux-restricted-modules-4.13.0-17-generic N/A
 linux-backports-modules-4.13.0-17-generic N/A
 linux-firmware 1.169
RfKill: Error: [Errno 2] No such file or directory
Tags: artful
Uname: Linux 4.13.0-17-generic x86_64
UnreportableReason: The report belongs to a package that is not installed.
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups:

_MarkForUpload: False
dmi.bios.date: 12/17/2015
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 2.0
dmi.board.asset.tag: Default string
dmi.board.name: X10SRD-F
dmi.board.vendor: Supermicro
dmi.board.version: 1.01
dmi.chassis.asset.tag: Default string
dmi.chassis.type: 17
dmi.chassis.vendor: Supermicro
dmi.chassis.version: 0123456789
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr2.0:bd12/17/2015:svnSupermicro:pnSuperServer:pvr0123456789:rvnSupermicro:rnX10SRD-F:rvr1.01:cvnSupermicro:ct17:cvr0123456789:
dmi.product.family: Default string
dmi.product.name: Super Server
dmi.product.version: 0123456789
dmi.sys.vendor: Supermicro

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 1734327

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Sergey Kozlov (skozlov)]

apport information

[Sergey Kozlov (skozlov)]

apport information

[Sergey Kozlov (skozlov)]

apport information

[Sergey Kozlov (skozlov)]

apport information

[Sergey Kozlov (skozlov)]

apport information

[Sergey Kozlov (skozlov)]

apport information

[Sergey Kozlov (skozlov)]

apport information

[Sergey Kozlov (skozlov)]

apport information

[Sergey Kozlov (skozlov)]

apport information

[Sergey Kozlov (skozlov)]

apport information

[Sergey Kozlov (skozlov)]

apport information

[Joseph Salisbury (jsalisbury)]

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v4.14 kernel[0].

If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

Thanks in advance.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.14

[Sergey Kozlov (skozlov)]

Unable to reproduce using upstream kernel 4.14.0-041400-generic.

[Joseph Salisbury (jsalisbury)]

I'd like to perform a reverse bisect to figure out which commit upstream fixes this regression. It would be very helpful to know the last kernel that had this issue and the first kernel that did not.

Can you test the following kernels and report back? We are looking for the earliest kernel version that does not have this bug:

v4.13 final: http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.13/
v4.14-rc1: http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.14-rc1/

Thanks in advance!

[Sergey Kozlov (skozlov)]

Unable to reproduce with both 4.13.0 and 4.14-rc1

[Joseph Salisbury (jsalisbury)]

Can you give 4.13-rc1 a try:
http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.13-rc1/

[Sergey Kozlov (skozlov)]

4.13-rc1 is not affected either.

[Joseph Salisbury (jsalisbury)]

I wonder if this bug could be caused by a SAUCE patch, which is why it doesn't happen with the upstream kernels.

Can you see if this bug happens in either the Zesty kernel or Artful -proposed

Zesty: https://launchpad.net/~canonical-kernel-team/+archive/ubuntu/ppa/+build/13757667
Artful -proposed: https://launchpad.net/~canonical-kernel-team/+archive/ubuntu/ppa/+build/13757328

With these kernels, you need to install both the linux-image and linux-image-extra .deb packages.

[Sergey Kozlov (skozlov)]

4.13.0-18 is affected.
4.10.0-41 is not affected.

[Joseph Salisbury (jsalisbury)]

Thanks for testing, Sergey. That further indicates that the regression is due to a SAUCE patch. We can perform a bisect to identify the exact commit. We need to narrow down the kernel version that introduced the bug further. Can you next test the following two kernels:

4.11.0-5: https://launchpad.net/~canonical-kernel-team/+archive/ubuntu/ppa/+build/12644289
4.12.0-13: https://launchpad.net/ubuntu/+source/linux/4.12.0-13.14/+build/13325106

[Sergey Kozlov (skozlov)]

Both 4.11.0-5 and 4.12.0-13 are not affected.

[Joseph Salisbury (jsalisbury)]

Thanks again for testing. It's sounding like this was introduced by a SAUCE patch in the 4.13 kernel. Can you next test the first 4.13 kernel that came after 4.12.0-13:

4.13.0-10: https://launchpad.net/~canonical-kernel-team/+archive/ubuntu/unstable/+build/13358561

[Sergey Kozlov (skozlov)]

4.13.0-10 is not affected.

[Joseph Salisbury (jsalisbury)]

Can you next try 4.13.0-14:
https://launchpad.net/ubuntu/+source/linux/4.13.0-14.15/+build/13541235

[Sergey Kozlov (skozlov)]

4.13.0-14 is affected.

[Sergey Kozlov (skozlov)]

Tried 4.13.0-12 from https://launchpad.net/~canonical-kernel-team/+archive/ubuntu/ppa/+build/13498518, it's not affected.

[Joseph Salisbury (jsalisbury)]

I started a kernel bisect between 4.13.0-12 and 4.13.0-14. The kernel bisect will require testing of about 7-10 test kernels.

I built the first test kernel, up to the following commit:
1c8d41925cff57972056048511a451040fa3b790

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1734327

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

[Sergey Kozlov (skozlov)]

4.13.0-13-generic #14~lp1734327Commit1c8d41925cf is not affected.

[Joseph Salisbury (jsalisbury)]

I built the next test kernel, up to the following commit:
8d9d2235a82ea41e65eff607005ea4f334e2e503

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1734327

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

[Sergey Kozlov (skozlov)]

4.13.0-13-generic #14~lp1734327Commit8d9d2235a82 is affected.

[Joseph Salisbury (jsalisbury)]

Two commits that stick out in the git log are:
4ae2508 UBUNTU: SAUCE: LSM stacking: add stacking support to apparmor network hooks
ac8f82a UBUNTU: SAUCE: LSM stacking: LSM: Infrastructure management of the remaining blobs

I built a test kernel with these two commits reverted.

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1734327/revert-test

Can you test that kernel and report back if it has the bug or not?

[Sergey Kozlov (skozlov)]

4.13.0-17-generic #20~lp1734327 kernel with commits reverted is not affected.

Thanks for all your effort.

[Joseph Salisbury (jsalisbury)]

I built one more test kernel. This one only has commit 4ae2508 reverted.

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1734327/revert-test

Can you test that kernel and report back if it has the bug or not?

[Sergey Kozlov (skozlov)]

4.13.0-17-generic #20~lp1734327JustCommit4ae2508Reverted is affected.

[Joseph Salisbury (jsalisbury)]

SRU request submitted:
https://lists.ubuntu.com/archives/kernel-team/2017-December/088715.html

[Joseph Salisbury (jsalisbury)]

I built a test kernel with the patch from Tetsuo. The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1734327

Can you test this kernel and see if it resolves this bug?

Note, to test this kernel, you need to install both the linux-image and linux-image-extra .deb packages.

Thanks in advance!

[Sergey Kozlov (skozlov)]

4.13.0-32-generic #35~lp1734327 is not affected.

[Joseph Salisbury (jsalisbury)]

That's good news, thanks for testing, Sergey.

Tetsuo, do you know if your patch is going to land upstream?

[Tetsuo Handa (9-launchpad-i-love-sakura-ne-jp)]

No plan to land upstream yet. Casey's upstream proposal
( http://kernsec.org/pipermail/linux-security-module-archive/2017-December/004728.html ) is stalling.
Please carry my patch as UBUNTU: SAUCE: patch.

[Joseph Salisbury (jsalisbury)]

I'm wondering if we want to see what type of feedback is first received from upstream.

[Tetsuo Handa (9-launchpad-i-love-sakura-ne-jp)]

Since 18.04 seems to give up LSM stacking patchset, safest choice (if
acceptable) would be to completely revert LSM stacking patchset for
17.10 as well.

[Brad Figg (brad-figg)]

This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-artful' to 'verification-done-artful'. If the problem still exists, change the tag 'verification-needed-artful' to 'verification-failed-artful'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Sergey Kozlov (skozlov)]

Fix verified on linux-image-4.13.0-39-generic/artful-proposed.

Thank you for the great work!

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux - 4.13.0-39.44

---------------
linux (4.13.0-39.44) artful; urgency=medium

  * linux: 4.13.0-39.44 -proposed tracker (LP: #1761456)

  * intel-microcode 3.20180312.0 causes lockup at login screen(w/ linux-
    image-4.13.0-37-generic) (LP: #1759920) // CVE-2017-5715 (Spectre v2
    Intel) // CVE-2017-5754
    - x86/mm: Reinitialize TLB state on hotplug and resume

  * intel-microcode 3.20180312.0 causes lockup at login screen(w/ linux-
    image-4.13.0-37-generic) (LP: #1759920) // CVE-2017-5715 (Spectre v2 Intel)
    - Revert "x86/mm: Only set IBPB when the new thread cannot ptrace current
      thread"
    - x86/speculation: Use Indirect Branch Prediction Barrier in context switch

  * DKMS driver builds fail with: Cannot use CONFIG_STACK_VALIDATION=y, please
    install libelf-dev, libelf-devel or elfutils-libelf-devel (LP: #1760876)
    - [Packaging] include the retpoline extractor in the headers

  * retpoline hints: primary infrastructure and initial hints (LP: #1758856)
    - [Packaging] retpoline-extract: flag *0xNNN(%reg) branches
    - x86/speculation, objtool: Annotate indirect calls/jumps for objtool
    - x86/speculation, objtool: Annotate indirect calls/jumps for objtool on 32bit
    - x86/paravirt, objtool: Annotate indirect calls
    - [Packaging] retpoline -- add safe usage hint support
    - [Packaging] retpoline-check -- only report additions
    - [Packaging] retpoline -- widen indirect call/jmp detection
    - [Packaging] retpoline -- elide %rip relative indirections
    - [Packaging] retpoline -- clear hint information from packages
    - KVM: x86: Make indirect calls in emulator speculation safe
    - KVM: VMX: Make indirect call speculation safe
    - x86/boot, objtool: Annotate indirect jump in secondary_startup_64()
    - SAUCE: early/late -- annotate indirect calls in early/late initialisation
      code
    - SAUCE: vga_set_mode -- avoid jump tables
    - [Config] retpoline -- switch to new format
    - [Packaging] retpoline hints -- handle missing files when RETPOLINE not
      enabled
    - [Packaging] final-checks -- remove check for empty retpoline files

  * retpoline: ignore %cs:0xNNN constant indirections (LP: #1752655)
    - [Packaging] retpoline -- elide %cs:0xNNNN constants on i386

  * zfs system process hung on container stop/delete (LP: #1754584)
    - SAUCE: Fix non-prefaulted page deadlock (LP: #1754584)

  * zfs-linux 0.6.5.11-1ubuntu5 ADT test failure with linux 4.15.0-1.2
    (LP: #1737761)
    - SAUCE: (noup) Update zfs to 0.6.5.11-1ubuntu3.2

  * AT_BASE_PLATFORM in AUXV is absent on kernels available on Ubuntu 17.10
    (LP: #1759312)
    - powerpc/64s: Fix NULL AT_BASE_PLATFORM when using DT CPU features

  * btrfs and tar sparse truncate archives (LP: #1757565)
    - Btrfs: move definition of the function btrfs_find_new_delalloc_bytes
    - Btrfs: fix reported number of inode blocks after buffered append writes

  * efifb broken on ThunderX-based Gigabyte nodes (LP: #1758375)
    - drivers/fbdev/efifb: Allow BAR to be moved instead of claiming it

  * Intel i40e PF reset due to incorrect MDD detection (continues...)
    (LP: #1723127)
    - i40e/i40ev...