Please backport fix to reference leak in cgroup blkio throttle

[Chunwei Chen]

This is fixed in Linux 4.5
https://github.com/torvalds/linux/commit/39a169b62b415390398291080dafe63aec751e0a

Basically the module reference will leak whenever you write to /sys/fs/cgroup/blkio/blkio.throttle.*

$ uname -a
Linux david-kvm 4.4.0-72-generic #93-Ubuntu SMP Fri Mar 31 14:07:41 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
$ lsmod | grep ^zfs
zfs 2813952 1
$ sudo sh -c 'i=100; while [ $i -gt 0 ]; do echo "230:0 1024" > /sys/fs/cgroup/blkio/blkio.throttle.read_bps_device; i=$(($i - 1)); done'
$ lsmod | grep ^zfs
zfs 2813952 101

This patch should be applied to all kernel < 4.5

Thanks

[Brad Figg (brad-figg)]

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

apport-collect 1683976

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.

[Joseph Salisbury (jsalisbury)]

I built a Trusty and Xenial test kernel with commit 39a169b62b41. These test kernels can be downloaded from:

http://kernel.ubuntu.com/~jsalisbury/lp1683976/

Can you test one of these kernel and post back if it resolves this bug?

Thanks in advance!

[Chunwei Chen (david-chen)]

Hi Joseph,

I just tested the Xenial one and it fixed the issue.

Thanks for the quick respond.

[Kleber Sacilotto de Souza (kleber-souza)]

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!

[Chunwei Chen (david-chen)]

Verified on 4.4.0-78-generic

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

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!

[Chunwei Chen (david-chen)]

Verified on 3.13.0-119-generic

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux - 3.13.0-119.166

---------------
linux (3.13.0-119.166) trusty; urgency=low

  * linux: 3.13.0-119.166 -proposed tracker (LP: #1687718)

  * CVE-2016-8645: Linux kernel mishandles socket buffer (skb) truncation
    (LP: #1687107)
    - rose: limit sk_filter trim to payload
    - tcp: take care of truncations done by sk_filter()

linux (3.13.0-118.165) trusty; urgency=low

  * linux: 3.13.0-118.165 -proposed tracker (LP: #1686154)

  * linux_3.13.0-*.*: nVMX: Check current_vmcs12 before accessing in
    handle_invept() (LP: #1678676)
    - SAUCE: KVM has a flaw in INVEPT emulation that could crash the host

  * Please backport fix to reference leak in cgroup blkio throttle
    (LP: #1683976)
    - block: fix module reference leak on put_disk() call for cgroups throttle

 -- Thadeu Lima de Souza Cascardo <email address hidden> Tue, 02 May 2017 15:14:50 -0300

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux - 4.4.0-78.99

---------------
linux (4.4.0-78.99) xenial; urgency=low

  * linux: 4.4.0-78.99 -proposed tracker (LP: #1686645)

  * Please backport fix to reference leak in cgroup blkio throttle
    (LP: #1683976)
    - block: fix module reference leak on put_disk() call for cgroups throttle

  * UbuntuKVM guest crashed while running I/O stress test with Ubuntu kernel
    4.4.0-47-generic (LP: #1659111)
    - block: Unhash block device inodes on gendisk destruction
    - block: Use pointer to backing_dev_info from request_queue
    - block: Dynamically allocate and refcount backing_dev_info
    - block: Make blk_get_backing_dev_info() safe without open bdev
    - block: Get rid of blk_get_backing_dev_info()
    - block: Move bdev_unhash_inode() after invalidate_partition()
    - block: Unhash also block device inode for the whole device
    - block: Revalidate i_bdev reference in bd_aquire()
    - block: Initialize bd_bdi on inode initialization
    - block: Move bdi_unregister() to del_gendisk()
    - block: Allow bdi re-registration
    - bdi: Fix use-after-free in wb_congested_put()
    - block: Make del_gendisk() safer for disks without queues
    - block: Fix bdi assignment to bdev inode when racing with disk delete
    - bdi: Mark congested->bdi as internal
    - bdi: Make wb->bdi a proper reference
    - bdi: Unify bdi->wb_list handling for root wb_writeback
    - bdi: Shutdown writeback on all cgwbs in cgwb_bdi_destroy()
    - bdi: Do not wait for cgwbs release in bdi_unregister()
    - bdi: Rename cgwb_bdi_destroy() to cgwb_bdi_unregister()
    - block: Fix oops in locked_inode_to_wb_and_lock_list()
    - kobject: Export kobject_get_unless_zero()
    - block: Fix oops scsi_disk_get()

  * Touchpad not working correctly after kernel upgrade (LP: #1662589)
    - Input: ALPS - fix V8+ protocol handling (73 03 28)

  * Xenial update to v4.4.62 stable release (LP: #1683728)
    - drm/i915: Avoid tweaking evaluation thresholds on Baytrail v3
    - drm/i915: Stop using RP_DOWN_EI on Baytrail
    - usb: dwc3: gadget: delay unmap of bounced requests
    - mtd: bcm47xxpart: fix parsing first block after aligned TRX
    - MIPS: Introduce irq_stack
    - MIPS: Stack unwinding while on IRQ stack
    - MIPS: Only change $28 to thread_info if coming from user mode
    - MIPS: Switch to the irq_stack in interrupts
    - MIPS: Select HAVE_IRQ_EXIT_ON_IRQ_STACK
    - MIPS: IRQ Stack: Fix erroneous jal to plat_irq_dispatch
    - crypto: caam - fix RNG deinstantiation error checking
    - Linux 4.4.62

  * ifup service of network device stay active after driver stop (LP: #1672144)
    - net: use net->count to check whether a netns is alive or not

  * [Hyper-V] mkfs regression in kernel 4.4+ (LP: #1682215)
    - block: relax check on sg gap

  * [Feature] KBL: intel_powerclamp driver support (LP: #1591641)
    - thermal/powerclamp: remove cpu whitelist
    - thermal/powerclamp: correct cpu support check
    - thermal/powerclamp: add back module device table

  * sysfs channel reads of lps22hb pressure sensor are stale (LP: #1682103)
    - iio: st_pressure: initialize lps22hb bootime

  * Backlight control does no...