919901 - B2G Emulator: A signal dispatching bug in Linux 2.6.29

Status: RESOLVED FIXED

(Firefox OS Graveyard :: Emulator, defect)

Description

[Ting-Yuan Huang]

We need this fix or all the signal handlers can only work by chance on Linux 2.6.29 + goldfish-armv7, which is the default configuration of the Firefox OS emulator.

commit d71e1352e240dea32d481ad8d662e8de4406ac7e
Author: Catalin Marinas <[e-mail]>
Date:   Sat May 30 14:00:15 2009 +0100

    Clear the IT state when invoking a Thumb-2 signal handler
    
    If a process is interrupted during an If-Then block and a signal is
    invoked, the ITSTATE bits must be cleared otherwise the handler would
    not run correctly.
    
    Signed-off-by: Catalin Marinas <[e-mail]>
    Cc: Joseph S. Myers <[e-mail]>

Comment 1

[Vicamo Yang [:vicamo][:vyang]]

Attachment: Github pull request for kernel_goldfish

Comment 2

[Vicamo Yang [:vicamo][:vyang]]

Attachment: Github pull request for prebuilts/qemu-kernel

Comment 3

[Vicamo Yang [:vicamo][:vyang]]

Attachment: Github pull request for b2g-manifest

For jellybean, its qemu-kernel HEAD is now AOSP tag "android-4.3_r2.1".  We have to track master branch of Mozilla's fork as we have done to B2G ICS to include prebuilt kernel images here.

The qemu-kernel project entry was placed in `base-jb.xml` and is moved to `emulator-jb.xml` in this patch.

Comment 4

[Michael Wu [:mwu]]

I think we actually rely on prebuilts/qemu-kernel, so it can't be removed from base-jb.xml. See build/core/Makefile. I haven't actually tested in a while, so lemme know if that somehow doesn't apply anymore.

Comment 5

[Michael Wu [:mwu]]

Also, we shouldn't bother upgrading the JB emulator to a fixed 2.6.29 kernel - we can just use 3.4 there. We should modify our emulator launcher script to use the 3.4 kernel.

Comment 6

[Vicamo Yang [:vicamo][:vyang]]

(In reply to Michael Wu [:mwu] from comment #4)
> I think we actually rely on prebuilts/qemu-kernel, so it can't be removed
> from base-jb.xml. See build/core/Makefile. I haven't actually tested in a
> while, so lemme know if that somehow doesn't apply anymore.

Thanks.

(In reply to Michael Wu [:mwu] from comment #5)
> Also, we shouldn't bother upgrading the JB emulator to a fixed 2.6.29 kernel
> - we can just use 3.4 there. We should modify our emulator launcher script
> to use the 3.4 kernel.

The qemu-kernel history tree looks like:

  *  commit cc1a057
  |\ summary: Merge "chage default kernel to 3.4"
  | \
  |  * commit 384a196
  | /  summary: chage default kernel to 3.4
  |/
  *  commit ec4a882
  |\ summary: Merge "update 3.4 kernel from commit fb3ea4f"
  | \
  |  |
  |  * commit 5145627 (tag: refs/tags/android-4.3_r2.1) <---------- Gonk JB is here
  |  | summary: update 3.4 kernel from commit fb3ea4f

Before commit 384a196 (chage default kernel to 3.4), we have file system layout:

  .
  |-- arm
  |   |-- 3.4
  |   |   |-- kernel-qemu-armv7
  |   |   `-- vmlinux-qemu-armv7
  |   |-- kernel-qemu-armv7
  |   `-- vmlinux-qemu-armv7

And after:

  .
  |-- arm
  |   |-- 2.6
  |   |   |-- kernel-qemu-armv7
  |   |   `-- vmlinux-qemu-armv7
  |   |-- kernel-qemu-armv7
  |   `-- vmlinux-qemu-armv7

Considering we may have to merge further kernel changes like:

  * commit eb4c2db - fix device lock-up in the kernel space
  * commit 1d8f0ba - enable NSA SELinux support
  ...

then we'll have to revert the change we've done to emulator launcher script to pick up correct kernel images again.  What about:

  1) branch qemu-kernel,
  2) pin the initial HEAD to commit cc1a057 (Merge "chage default kernel to 3.4")
  3) update kernel images with GitHub PR (attachment 809077 [details]) included

This way, we always know how many changes are included in current kernel images and we'll always use kernel images directly under prebuilts/qemu-kernel.  What do you think?

Comment 7

[Ting-Yuan Huang]

Comment on attachment 809079 [details]
Github pull request for prebuilts/qemu-kernel

Tested several times and it seemed to work correctly. No failures observed. Without this it always fails against patches in bug 899493.

Comment 8

[Vicamo Yang [:vicamo][:vyang]]

Merged on GitHub:
https://github.com/mozilla-b2g/kernel_goldfish/commit/e2ba18df308001e1dcba97ba932c92ff33a53cbe
https://github.com/mozilla-b2g/platform_prebuilts_qemu-kernel/commit/83dbccadb19d0d3c07828c2bb0e5c2be12c0f980

Comment 9

[Vicamo Yang [:vicamo][:vyang]]

Comment on attachment 809113 [details]
Github pull request for b2g-manifest

Not going to update JB kernel, although it's also tested.  Leave JB unfixed and buy us some time to have a chance to re-evaluate the work needed to upgrade JB kernel to 3.4 directly.

Comment 10

[Vicamo Yang [:vicamo][:vyang]]

Adopted in http://git.mozilla.org/?p=b2g/platform_prebuilts_qemu-kernel.git;a=commit;h=83dbccadb19d0d3c07828c2bb0e5c2be12c0f980

Comment 11

[Vicamo Yang [:vicamo][:vyang]]

(In reply to Vicamo Yang [:vicamo][:vyang] from comment #9)
> Comment on attachment 809113 [details]
> Github pull request for b2g-manifest
> 
> Not going to update JB kernel, although it's also tested.  Leave JB unfixed
> and buy us some time to have a chance to re-evaluate the work needed to
> upgrade JB kernel to 3.4 directly.

This part is automatically included because of bug 916863 (emulator NFC).