VM: Fix deadlock in time line recording.

VM: Fix deadlock in time line recording

BUG=#25189

[Florian Schneider, 2015-12-09 14:49:41]

fschneider@google.com changed reviewers:
+ iposva@google.com, johnmccutchan@google.com, turnidge@google.com

[Florian Schneider, 2015-12-09 14:49:42]

Windows to be implemented if this looks good.

[Ivan Posva, 2015-12-09 16:34:57]

Florian,

Thanks for identifying the recursive locking issue. We will need to change it in
a different way though.

-Ivan

https://codereview.chromium.org/1515553003/diff/1/runtime/vm/os_thread.h
File runtime/vm/os_thread.h (right):

https://codereview.chromium.org/1515553003/diff/1/runtime/vm/os_thread.h#newc...
runtime/vm/os_thread.h:250: explicit Mutex(bool recursive = false);
The class Mutex is defined to not ever be recursive. If we have such a case then
the algorithm needs to be updated.

[Florian Schneider, 2015-12-10 14:44:21]

https://codereview.chromium.org/1515553003/diff/1/runtime/vm/os_thread.h
File runtime/vm/os_thread.h (right):

https://codereview.chromium.org/1515553003/diff/1/runtime/vm/os_thread.h#newc...
runtime/vm/os_thread.h:250: explicit Mutex(bool recursive = false);
On 2015/12/09 16:34:57, Ivan Posva wrote:
> The class Mutex is defined to not ever be recursive. If we have such a case
then
> the algorithm needs to be updated.

What would break otherwise? I didn't see any tests failing, so at least there is
no test coverage of this assumption.

[Ivan Posva, 2015-12-11 19:25:23]

Description was changed from

==========
VM: Fix deadlock in time line recording

BUG=#25189
==========

to

==========
VM: Fix deadlock in time line recording

BUG=#25189
==========

[Ivan Posva, 2015-12-11 19:25:47]

Closing this issue as it has become obsolete.

-Ivan