Re: [Masf-restricted-dev] CR/CN: Fixed thread-safety issues in HXScheduler

Excellent find and fix!!!

Please commit to the following additional branches as well:
hxclient_3_1_0_atlas
HEAD

Thanks,
Milko

At 06:14 PM 9/5/2008, Petar Basic wrote:
>Modified by: pbasic at real.com
>Date: 2008/09/06
>Project: strummer
>
>Synopsis:
>Fixed thread-safety issues in HXScheduler
>
>Details:
>There was a race condition in ClientPQ class.
>ClientPQ is derived from PQ which accepts CHXID object as an argument
>to the constructor.  ClientPQ is obviously designed as a thread-safe
>wrapper around PQ, but each instance of ClientPQ uses its own mutex
>object.  However, this is not enough.  Since CHXID object can be
>shared among PQ instances, it must be protected by a single mutex.
>Instantiations of ClientPQ in HXScheduler are critical to this case
>since HXScheduler uses 3 ClientPQ objects which share a single CHXID.
>HXOptimizedScheduler currently uses only 1 ClientPQ object.
>
>1.) Additional assert statements which can detect race condition have
>been added to CHXID class.
>2.) ClientPQ is modified to accept externally created mutex.  In this
>way CHXID object can be protected through common mutex by multiple
>ClientPQ instances.
>3.) Destruction of PQ base in ClientPQ destructor has been made thread-safe.
>4.) HXScheduler has been modified to use a single mutex with all of
>its ClientPQ instances.
>5.) Although it was not necessary at this time, HXOptimizedScheduler
>has been modified in the same way as HXScheduler to prepare it for
>possible future updates.
>
>Testing:
>Performed over 1200 transcoding transfers to USB memory during single
>VFMM session without crashes or lockups.  Also performed simultaneous
>transfers to 2 USB devices without crashes or lockups.
>
>Files Modified:
>common/util/pub/id.h
>common/system/pub/pq.h
>common/system/pq.cpp
>client/common/system/pub/clientpq.h
>client/common/system/clientpq.cpp
>client/common/system/pub/hxsched.h
>client/common/system/hxsched.cpp
>client/common/system/pub/hxoptsc.h
>client/common/system/hxoptsc.cpp
>
>Platforms and Profiles Build Verified:
>system id: win32-i386-vc7
>profile: helix-dtdr-all-defines
>
>Platforms and Profiles Functionality Verified:
>x86 Windows XP SP2
>
>Branch:
>hxclient_3_4_0_atlas
>
>Copyright assignment:
>I am a RealNetworks employee or contractor.
>
>Content-Type: application/octet-stream; name="common_util.diff"
>X-Attachment-Id: f_fkrjl7q00
>Content-Disposition: attachment; filename=common_util.diff
>
>Content-Type: application/octet-stream; name="common_system.diff"
>X-Attachment-Id: f_fkrjlb201
>Content-Disposition: attachment; filename=common_system.diff
>
>Content-Type: application/octet-stream; name="client_common_system.diff"
>X-Attachment-Id: f_fkrjld282
>Content-Disposition: attachment; filename=client_common_system.diff
>
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