[Hyper-V] Fix ring buffer handling to avoid host throttling

Bug #1661430 reported by Joshua R. Poulson on 2017-02-02
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
linux (Ubuntu)
Medium
Tim Gardner
Xenial
Medium
Tim Gardner
Yakkety
Medium
Tim Gardner
Zesty
Medium
Tim Gardner

Bug Description

An unfortunate side effect of some of the recent work done to improve ring buffer performance made a situation where the host would interpret guest requests as a denial of service attack, pausing guest communications for five seconds. This series of fixes corrects this problem.

Needed for each kernel that has included a389fcfd2cb5 ("Drivers: hv: vmbus: Fix signaling logic in hv_need_to_signal_on_read()")

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=74198eb4a42c4a3c4fbef08fa01a291a282f7c2e

Drivers: hv: vmbus: Base host signaling strictly on the ring state
One of the factors that can result in the host concluding that a given
guest in mounting a DOS attack is if the guest generates interrupts
to the host when the host is not expecting it. If these "spurious"
interrupts reach a certain rate, the host can throttle the guest to
minimize the impact. The host computation of the "expected number
of interrupts" is strictly based on the ring transitions. Until
the host logic is fixed, base the guest logic to interrupt solely
on the ring state.

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=1f6ee4e7d83586c8b10bd4f2f4346353d04ce884

Drivers: hv: vmbus: On write cleanup the logic to interrupt the host
Signal the host when we determine the host is to be signaled.
The currrent code determines the need to signal in the ringbuffer
code and actually issues the signal elsewhere. This can result
in the host viewing this interrupt as spurious since the host may also
poll the channel. Make the necessary adjustments.

https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/?id=3372592a140db69fd63837e81f048ab4abf8111e

Drivers: hv: vmbus: On the read path cleanup the logic to interrupt the host
Signal the host when we determine the host is to be signaled -
on th read path. The currrent code determines the need to signal in the
ringbuffer code and actually issues the signal elsewhere. This can result
in the host viewing this interrupt as spurious since the host may also
poll the channel. Make the necessary adjustments.

https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/?id=433e19cf33d34bb6751c874a9c00980552fe508c

Drivers: hv: vmbus: finally fix hv_need_to_signal_on_read()
Commit a389fcfd2cb5 ("Drivers: hv: vmbus: Fix signaling logic in
hv_need_to_signal_on_read()")
added the proper mb(), but removed the test "prev_write_sz < pending_sz"
when making the signal decision.

As a result, the guest can signal the host unnecessarily,
and then the host can throttle the guest because the host
thinks the guest is buggy or malicious; finally the user
running stress test can perceive intermittent freeze of
the guest.

This patch brings back the test, and properly handles the
in-place consumption APIs used by NetVSC (see get_next_pkt_raw(),
put_pkt_raw() and commit_rd_index()).

Fixes: a389fcfd2cb5 ("Drivers: hv: vmbus: Fix signaling logic in
hv_need_to_signal_on_read()")

This bug is missing log files that will aid in diagnosing the problem. From a terminal window please run:

apport-collect 1661430

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.

Changed in linux (Ubuntu):
status: New → Incomplete
Joshua R. Poulson (jrp) wrote :

No logs, request to include upstream commits.

Changed in linux (Ubuntu):
status: Incomplete → Confirmed
Tim Gardner (timg-tpi) wrote :
Changed in linux (Ubuntu Xenial):
assignee: nobody → Tim Gardner (timg-tpi)
status: New → In Progress
Changed in linux (Ubuntu Yakkety):
assignee: nobody → Tim Gardner (timg-tpi)
status: New → In Progress
Changed in linux (Ubuntu Zesty):
assignee: nobody → Tim Gardner (timg-tpi)
status: Confirmed → Fix Committed
Changed in linux (Ubuntu Xenial):
importance: Undecided → Medium
Changed in linux (Ubuntu Yakkety):
importance: Undecided → Medium
Changed in linux (Ubuntu Zesty):
importance: Undecided → Medium
tags: added: kernel-da-key kernel-hyper-v
Changed in linux (Ubuntu Xenial):
status: In Progress → Fix Committed
Changed in linux (Ubuntu Yakkety):
status: In Progress → Fix Committed
Brad Figg (brad-figg) wrote :

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-xenial' to 'verification-done-xenial'. If the problem still exists, change the tag 'verification-needed-xenial' to 'verification-failed-xenial'.

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!

tags: added: verification-needed-xenial
tags: added: verification-needed-yakkety
Brad Figg (brad-figg) wrote :

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-yakkety' to 'verification-done-yakkety'. If the problem still exists, change the tag 'verification-needed-yakkety' to 'verification-failed-yakkety'.

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!

Launchpad Janitor (janitor) wrote :
Download full text (6.0 KiB)

This bug was fixed in the package linux - 4.8.0-40.43

---------------
linux (4.8.0-40.43) yakkety; urgency=low

  * linux: 4.8.0-40.43 -proposed tracker (LP: #1667066)

  [ Andy Whitcroft ]
  * NFS client : permission denied when trying to access subshare, since kernel
    4.4.0-31 (LP: #1649292)
    - fs: Better permission checking for submounts

  * shaking screen (LP: #1651981)
    - drm/radeon: drop verde dpm quirks

  * [0bda:0328] Card reader failed after S3 (LP: #1664809)
    - usb: hub: Wait for connection to be reestablished after port reset

  * linux-lts-xenial 4.4.0-63.84~14.04.2 ADT test failure with linux-lts-xenial
    4.4.0-63.84~14.04.2 (LP: #1664912)
    - SAUCE: apparmor: fix link auditing failure due to, uninitialized var

  * In Ubuntu 17.04 : after reboot getting message in console like Unable to
    open file: /etc/keys/x509_ima.der (-2) (LP: #1656908)
    - SAUCE: ima: Downgrade error to warning

  * 16.04.2: Extra patches for POWER9 (LP: #1664564)
    - powerpc/mm: Fix no execute fault handling on pre-POWER5
    - powerpc/mm: Fix spurrious segfaults on radix with autonuma

  * ibmvscsis: Add SGL LIMIT (LP: #1662551)
    - ibmvscsis: Add SGL limit

  * [Hyper-V] Bug fixes for storvsc (tagged queuing, error conditions)
    (LP: #1663687)
    - scsi: storvsc: Enable tracking of queue depth
    - scsi: storvsc: Remove the restriction on max segment size
    - scsi: storvsc: Enable multi-queue support
    - scsi: storvsc: use tagged SRB requests if supported by the device
    - scsi: storvsc: properly handle SRB_ERROR when sense message is present
    - scsi: storvsc: properly set residual data length on errors

  * Ubuntu16.10-KVM:Big configuration with multiple guests running SRIOV VFs
    caused KVM host hung and all KVM guests down. (LP: #1651248)
    - KVM: PPC: Book 3S: XICS cleanup: remove XICS_RM_REJECT
    - KVM: PPC: Book 3S: XICS: correct the real mode ICP rejecting counter
    - KVM: PPC: Book 3S: XICS: Fix potential issue with duplicate IRQ resends
    - KVM: PPC: Book 3S: XICS: Implement ICS P/Q states
    - KVM: PPC: Book 3S: XICS: Don't lock twice when checking for resend

  * ISST-LTE:pNV: ppc64_cpu command is hung w HDs, SSDs and NVMe (LP: #1662666)
    - blk-mq: Avoid memory reclaim when remapping queues
    - blk-mq: Fix failed allocation path when mapping queues
    - blk-mq: Always schedule hctx->next_cpu

  * systemd-udevd hung in blk_mq_freeze_queue_wait testing unpartitioned NVMe
    drive (LP: #1662673)
    - percpu-refcount: fix reference leak during percpu-atomic transition

  * [Yakkety SRU] Enable KEXEC support in ARM64 kernel (LP: #1662554)
    - [Config] Enable KEXEC support in ARM64.

  * [Hyper-V] Fix ring buffer handling to avoid host throttling (LP: #1661430)
    - Drivers: hv: vmbus: On write cleanup the logic to interrupt the host
    - Drivers: hv: vmbus: On the read path cleanup the logic to interrupt the host
    - Drivers: hv: vmbus: finally fix hv_need_to_signal_on_read()

  * brd module compiled as built-in (LP: #1593293)
    - CONFIG_BLK_DEV_RAM=m

  * regession tests failing after stackprofile test is run (LP: #1661030)
    - SAUCE: fix regression with domain change in compla...

Read more...

Changed in linux (Ubuntu Yakkety):
status: Fix Committed → Fix Released
Launchpad Janitor (janitor) wrote :
Download full text (14.5 KiB)

This bug was fixed in the package linux - 4.4.0-65.86

---------------
linux (4.4.0-65.86) xenial; urgency=low

  * linux: 4.4.0-65.86 -proposed tracker (LP: #1667052)

  [ Stefan Bader ]
  * Upgrade Redpine RS9113 driver to support AP mode (LP: #1665211)
    - SAUCE: Redpine driver to support Host AP mode

  * NFS client : permission denied when trying to access subshare, since kernel
    4.4.0-31 (LP: #1649292)
    - fs: Better permission checking for submounts

  * [Hyper-V] SAUCE: pci-hyperv fixes for SR-IOV on Azure (LP: #1665097)
    - SAUCE: PCI: hv: Fix wslot_to_devfn() to fix warnings on device removal
    - SAUCE: pci-hyperv: properly handle pci bus remove
    - SAUCE: pci-hyperv: lock pci bus on device eject

  * [Hyper-V/Azure] Please include Mellanox OFED drivers in Azure kernel and
    image (LP: #1650058)
    - net/mlx4_en: Fix bad WQE issue
    - net/mlx4_core: Fix racy CQ (Completion Queue) free
    - net/mlx4_core: Fix when to save some qp context flags for dynamic VST to VGT
      transitions
    - net/mlx4_core: Avoid command timeouts during VF driver device shutdown

  * Xenial update to v4.4.49 stable release (LP: #1664960)
    - ARC: [arcompact] brown paper bag bug in unaligned access delay slot fixup
    - selinux: fix off-by-one in setprocattr
    - Revert "x86/ioapic: Restore IO-APIC irq_chip retrigger callback"
    - cpumask: use nr_cpumask_bits for parsing functions
    - hns: avoid stack overflow with CONFIG_KASAN
    - ARM: 8643/3: arm/ptrace: Preserve previous registers for short regset write
    - target: Don't BUG_ON during NodeACL dynamic -> explicit conversion
    - target: Use correct SCSI status during EXTENDED_COPY exception
    - target: Fix early transport_generic_handle_tmr abort scenario
    - target: Fix COMPARE_AND_WRITE ref leak for non GOOD status
    - ARM: 8642/1: LPAE: catch pending imprecise abort on unmask
    - mac80211: Fix adding of mesh vendor IEs
    - netvsc: Set maximum GSO size in the right place
    - scsi: zfcp: fix use-after-free by not tracing WKA port open/close on failed
      send
    - scsi: aacraid: Fix INTx/MSI-x issue with older controllers
    - scsi: mpt3sas: disable ASPM for MPI2 controllers
    - xen-netfront: Delete rx_refill_timer in xennet_disconnect_backend()
    - ALSA: seq: Fix race at creating a queue
    - ALSA: seq: Don't handle loop timeout at snd_seq_pool_done()
    - drm/i915: fix use-after-free in page_flip_completed()
    - Linux 4.4.49

  * NFS client : kernel 4.4.0-57 crash with nfsv4 enries in /etc/fstab
    (LP: #1650336)
    - SUNRPC: fix refcounting problems with auth_gss messages.

  * [0bda:0328] Card reader failed after S3 (LP: #1664809)
    - usb: hub: Wait for connection to be reestablished after port reset

  * linux-lts-xenial 4.4.0-63.84~14.04.2 ADT test failure with linux-lts-xenial
    4.4.0-63.84~14.04.2 (LP: #1664912)
    - SAUCE: apparmor: fix link auditing failure due to, uninitialized var

  * ibmvscsis: Add SGL LIMIT (LP: #1662551)
    - ibmvscsis: Add SGL limit

  * [Hyper-V] Bug fixes for storvsc (tagged queuing, error conditions)
    (LP: #1663687)
    - scsi: storvsc: Enable tracking of queue depth
    - scsi: storvsc: Remove the ...

Changed in linux (Ubuntu Xenial):
status: Fix Committed → Fix Released
Joshua R. Poulson (jrp) on 2017-03-03
tags: added: verification-done-xenial
removed: verification-needed-xenial
Joshua R. Poulson (jrp) wrote :

HWE verified as well.

tags: added: verification-done-yakkety
removed: verification-needed-yakkety
Po-Hsu Lin (cypressyew) on 2019-10-03
Changed in linux (Ubuntu):
status: Fix Committed → Fix Released
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