[Android] Fix a deadlock between telemetry and DeviceUtils.

[Android] Fix a deadlock between telemetry and DeviceUtils.

Many functions in Python's logging module grab a lock internally. Some
appear to do so before converting the provided message to a string via
its __str__ method.

Calling an object's __str__ method before calling a logging funciton
allows anything called by the __str__ method to log without the risk of
hitting a deadlock.

BUG=392869
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=282412

[jbudorick, 2014-07-10 17:11:55]

Calling the exception's __str__ method _before_ calling logging.warning means
that we do the DeviceUtils.RunShellCommand call before logging.warning gets to
grab the lock.

I'm working on a more general fix to prevent this from being an issue in the
future, but that's going to take a bit longer. This fix should resolve this
deadlock.

[tonyg, 2014-07-10 17:24:02]

lgtm

Nice!!

Before landing, please update the patch description itself w/ the email from the
email and the stuff you explained offline. It could be very helpful to someone
in the future.

https://codereview.chromium.org/385653002/diff/1/tools/telemetry/telemetry/pa...
File tools/telemetry/telemetry/page/page_runner.py (right):

https://codereview.chromium.org/385653002/diff/1/tools/telemetry/telemetry/pa...
tools/telemetry/telemetry/page/page_runner.py:280: logging.warning(e)
Should we get this one too?

[jbudorick, 2014-07-10 17:46:58]

https://codereview.chromium.org/385653002/diff/1/tools/telemetry/telemetry/pa...
File tools/telemetry/telemetry/page/page_runner.py (right):

https://codereview.chromium.org/385653002/diff/1/tools/telemetry/telemetry/pa...
tools/telemetry/telemetry/page/page_runner.py:280: logging.warning(e)
On 2014/07/10 17:24:02, tonyg wrote:
> Should we get this one too?

Yes, definitely. Good catch.

[jbudorick, 2014-07-10 17:55:11]

The CQ bit was checked by jbudorick@chromium.org

[commit-bot: I haz the power, 2014-07-10 17:57:09]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/jbudorick@chromium.org/385653002/20001

[commit-bot: I haz the power, 2014-07-10 20:16:17]

Change committed as 282412