mbox

[PULL,Xenial] arm64: pte fixes to avoid triggering BUG() in ext4

Message ID CALdTtnu=0zQ3GoBUMWrW-EPngJG=tYaxzJeTYP6cSfCXsOXQWA@mail.gmail.com
State New
Headers show

Pull-request

git://kernel.ubuntu.com/dannf/ubuntu-xenial.git lp1566518

Message

dann frazier April 5, 2016, 8:31 p.m. UTC
BugLink: http://bugs.launchpad.net/bugs/1566518

The following changes since commit 09d2b08839694169075e4fa1e27f3d9423e5586f:

  s390/crypto: provide correct file mode at device register.
(2016-04-05 15:29:41 +0100)

are available in the git repository at:

  git://kernel.ubuntu.com/dannf/ubuntu-xenial.git lp1566518

for you to fetch changes up to 31b9f3ccdff88a5ab1eab5dfb93e1db94cd9670a:

  arm64: Update PTE_RDONLY in set_pte_at() for PROT_NONE permission
(2016-04-05 14:23:57 -0600)

----------------------------------------------------------------
Catalin Marinas (2):
      arm64: Honour !PTE_WRITE in set_pte_at() for kernel mappings
      arm64: Update PTE_RDONLY in set_pte_at() for PROT_NONE permission

 arch/arm64/include/asm/pgtable.h | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

Comments

Tim Gardner April 5, 2016, 8:51 p.m. UTC | #1
On 04/05/2016 09:31 PM, Dann Frazier wrote:
> git://kernel.ubuntu.com/dannf/ubuntu-xenial.git lp1566518

Provenance ? These don't look well formed to me.
dann frazier April 5, 2016, 9:33 p.m. UTC | #2
On Tue, Apr 5, 2016 at 2:51 PM, Tim Gardner <tim.gardner@canonical.com> wrote:
> On 04/05/2016 09:31 PM, Dann Frazier wrote:
>> git://kernel.ubuntu.com/dannf/ubuntu-xenial.git lp1566518
>
> Provenance ? These don't look well formed to me.

Whups - you're right, sorry. Both are straight cherry-picks from
upstream, but I accidentally cherry-picked the first from my test
build tree, so it has the wrong upstream hash.

I've fixed and repushed.

  -dann
Tim Gardner April 6, 2016, 8:46 a.m. UTC | #3
On 04/05/2016 10:33 PM, Dann Frazier wrote:
> git://kernel.ubuntu.com/dannf/ubuntu-xenial.git lp1566518

That is quite a leap to go from an ext4 BUG to some page table patches.
Where is the intervening discussion ? I assume you have positive test
results for both of our arm64 platforms (e.g., Snapdragon).

I've applied this time because these appear to be destined for stable,
but proper SRU justification will require a bit more information.

rtg
dann frazier April 6, 2016, 7:10 p.m. UTC | #4
On Wed, Apr 6, 2016 at 2:46 AM, Tim Gardner <tim.gardner@canonical.com> wrote:
> On 04/05/2016 10:33 PM, Dann Frazier wrote:
>> git://kernel.ubuntu.com/dannf/ubuntu-xenial.git lp1566518
>
> That is quite a leap to go from an ext4 BUG to some page table patches.

Sorry, I didn't mean to imply it was an ext4 bug, just that the
symptom is an ext4 BUG(), caused by incorrect pte settings.
I've now expanded on the root cause in the description, but see the
upstream thread for the complete story.

> Where is the intervening discussion ?

I added a link to the upstream thread in the bug comments. I think
you'll find that there is a clear root cause to an issue that is 100%
reproducible on this platform.

> I assume you have positive test
> results for both of our arm64 platforms (e.g., Snapdragon).

I do [now :)]. I tested w/ a rebase of these patches on top of Paulo's
pull dragonboard request, and still have the blinken lights :)

> I've applied this time because these appear to be destined for stable,
> but proper SRU justification will require a bit more information.

Understood. Thanks!

  -dann

> rtg
> --
> Tim Gardner tim.gardner@canonical.com