Fix close/open corner cases

[Tim Gardner]

SRU Justification

[Impact]
Microsoft has asked for these 3 patches to be applied to the linux-azure-4.15 kernel.
The code has changed significantly from 4.15 to 5.6, so the patches are
quite different then current upstream. Hopefully I've captured the intent
if not the function in those patches.

[1] - Correct corner case where a close operation does not complete.
[2] - Fix a race when an OPEN is cancelled.
[3] - Fix a panic when allocating memory when a spinlock is held.

[Test Case]
none

[Potential regression]
These patches are all intended to accommodate boundary conditions. You shouldn't
experience any regression under normal use.

[Tim Gardner (timg-tpi)]

https://lists.ubuntu.com/archives/kernel-team/2021-March/118033.html

[Tim Gardner (timg-tpi)]

Microsoft has run the test kernel and verified that there are no longer any leaked handles.

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

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

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!

[Tim Gardner (timg-tpi)]

Verification done - see https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1918714/comments/5

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux-azure-4.15 - 4.15.0-1112.125

---------------
linux-azure-4.15 (4.15.0-1112.125) bionic; urgency=medium

  * bionic/linux-azure-4.15: 4.15.0-1112.125 -proposed tracker (LP: #1919518)

  * Please trust Canonical Livepatch Service kmod signing key (LP: #1898716)
    - [Config] azure: enable CONFIG_MODVERSIONS and CONFIG_ASM_MODVERSIONS
    - [Packaging] build canonical-certs.pem from branch/arch certs

  * Enforce CONFIG_DRM_BOCHS=m (LP: #1916290)
    - [Config] azure: Keep CONFIG_DRM_BOCHS disabled

  * linux-azure: Install PMEM modules by default (LP: #1921411)
    - [Packaging] azure: Move PMEM related modules to linux-modules

  * Fix close/open corner cases (LP: #1918714)
    - CIFS: Close open handle after interrupted close
    - CIFS: Do not miss cancelled OPEN responses
    - cifs: Fix memory allocation in __smb2_handle_cancelled_cmd()

  [ Ubuntu: 4.15.0-141.145 ]

  * bionic/linux: 4.15.0-141.145 -proposed tracker (LP: #1919536)
  * binary assembly failures with CONFIG_MODVERSIONS present (LP: #1919315)
    - [Packaging] quiet (nomially) benign errors in BUILD script
  * selftests: bpf verifier fails after sanitize_ptr_alu fixes (LP: #1920995)
    - bpf: Simplify alu_limit masking for pointer arithmetic
    - bpf: Add sanity check for upper ptr_limit
    - bpf, selftests: Fix up some test_verifier cases for unprivileged
  * Packaging resync (LP: #1786013)
    - update dkms package versions
  * CVE-2018-13095
    - xfs: More robust inode extent count validation
  * i40e PF reset due to incorrect MDD event (LP: #1772675)
    - i40e: change behavior on PF in response to MDD event
  * Bionic update: upstream stable patchset 2021-03-09 (LP: #1918330)
    - ACPI: sysfs: Prefer "compatible" modalias
    - ARM: dts: imx6qdl-gw52xx: fix duplicate regulator naming
    - wext: fix NULL-ptr-dereference with cfg80211's lack of commit()
    - net: usb: qmi_wwan: added support for Thales Cinterion PLSx3 modem family
    - drivers: soc: atmel: Avoid calling at91_soc_init on non AT91 SoCs
    - drivers: soc: atmel: add null entry at the end of at91_soc_allowed_list[]
    - KVM: x86/pmu: Fix HW_REF_CPU_CYCLES event pseudo-encoding in
      intel_arch_events[]
    - KVM: x86: get smi pending status correctly
    - xen: Fix XenStore initialisation for XS_LOCAL
    - leds: trigger: fix potential deadlock with libata
    - mt7601u: fix kernel crash unplugging the device
    - mt7601u: fix rx buffer refcounting
    - xen-blkfront: allow discard-* nodes to be optional
    - ARM: imx: build suspend-imx6.S with arm instruction set
    - netfilter: nft_dynset: add timeout extension to template
    - xfrm: Fix oops in xfrm_replay_advance_bmp
    - RDMA/cxgb4: Fix the reported max_recv_sge value
    - iwlwifi: pcie: use jiffies for memory read spin time limit
    - iwlwifi: pcie: reschedule in long-running memory reads
    - mac80211: pause TX while changing interface type
    - can: dev: prevent potential information leak in can_fill_info()
    - x86/entry/64/compat: Preserve r8-r11 in int $0x80
    - x86/entry/64/compat: Fix "x86/entry/64/compat: Preserve r8-r11 in int $0x80"
    - iommu/vt-d: Gracefully handle DMAR units...