String corruption observed on win7-stab bot

_From [rnk@google.com](https://code.google.com/u/rnk@google.com/) on March 08, 2012 17:54:55_

Observed here: http://build.chromium.org/p/client.drmemory/builders/win7-stab/builds/678/steps/Chromium%20%27unit%27%20tests/logs/stdio Search for symcache and you can find warnings like this:

[----------] 7 tests from GAIAInfoUpdateServiceTest
[ RUN ] GAIAInfoUpdateServiceTest.DownloadSuccess
[ OK ] GAIAInfoUpdateServiceTest.DownloadSuccess (93207 ms)
[ RUN ] GAIAInfoUpdateServiceTest.DownloadFailure
[ OK ] GAIAInfoUpdateServiceTest.DownloadFailure (90192 ms)
[ RUN ] GAIAInfoUpdateServiceTest.NoMigration
~~Dr.M~~ Unable to create temp file for symfile E:\chromium\src\build\Debug\drmemory.symcache/nMap> >::Pointer.txt
[ OK ] GAIAInfoUpdateServiceTest.NoMigration (90660 ms)
[ RUN ] GAIAInfoUpdateServiceTest.ShouldUseGAIAProfileInfo
~~Dr.M~~ Unable to create temp file for symfile E:\chromium\src\build\Debug\drmemory.symcache/nMap> >::Pointer.txt
[ OK ] GAIAInfoUpdateServiceTest.ShouldUseGAIAProfileInfo (89754 ms)
[ RUN ] GAIAInfoUpdateServiceTest.ScheduleUpdate
~~Dr.M~~ Unable to create temp file for symfile E:\chromium\src\build\Debug\drmemory.symcache/nMap> >::Pointer.txt
[ OK ] GAIAInfoUpdateServiceTest.ScheduleUpdate (89363 ms)
[ RUN ] GAIAInfoUpdateServiceTest.LogOut
~~Dr.M~~ Unable to create temp file for symfile E:\chromium\src\build\Debug\drmemory.symcache/nMap> >::Pointer.txt
[ OK ] GAIAInfoUpdateServiceTest.LogOut (90067 ms)
[ RUN ] GAIAInfoUpdateServiceTest.LogIn
~~Dr.M~~ Unable to create temp file for symfile E:\chromium\src\build\Debug\drmemory.symcache/nMap> >::Pointer.txt
[ OK ] GAIAInfoUpdateServiceTest.LogIn (91144 ms)
[----------] 7 tests from GAIAInfoUpdateServiceTest (634700 ms total)

[----------] 10 tests from ProfileInfoCacheTest
[ RUN ] ProfileInfoCacheTest.AddProfiles
[ OK ] ProfileInfoCacheTest.AddProfiles (344 ms)
[ RUN ] ProfileInfoCacheTest.DeleteProfile
[ OK ] ProfileInfoCacheTest.DeleteProfile (203 ms)
[ RUN ] ProfileInfoCacheTest.MutateProfile
[ OK ] ProfileInfoCacheTest.MutateProfile (250 ms)
[ RUN ] ProfileInfoCacheTest.Sort
~~Dr.M~~ Unable to create temp file for symfile E:\chromium\src\build\Debug\drmemory.symcache/T�`T�.txt
\~~Dr.M~~ Unable to create temp file for symfile E:\chromium\src\build\Debug\drmemory.symcache/T�`T�.txt
[ OK ] ProfileInfoCacheTest.Sort (182134 ms)
[ RUN ] ProfileInfoCacheTest.BackgroundModeStatus
[ OK ] ProfileInfoCacheTest.BackgroundModeStatus (234 ms)
[ RUN ] ProfileInfoCacheTest.HasMigrated
[ OK ] ProfileInfoCacheTest.HasMigrated (218 ms)
[ RUN ] ProfileInfoCacheTest.GAIAName
[ OK ] ProfileInfoCacheTest.GAIAName (250 ms)
[ RUN ] ProfileInfoCacheTest.GAIAPicture
[ OK ] ProfileInfoCacheTest.GAIAPicture (265 ms)
[ RUN ] ProfileInfoCacheTest.PersistGAIAPicture
[ OK ] ProfileInfoCacheTest.PersistGAIAPicture (234 ms)
[ RUN ] ProfileInfoCacheTest.EmptyGAIAInfo
[ OK ] ProfileInfoCacheTest.EmptyGAIAInfo (89629 ms)
[----------] 10 tests from ProfileInfoCacheTest (274060 ms total)

I spent a while looking at the symcache code, and it's trying to print modname into a buffer so it can open the symcache temp file. modname is from the mod_cache_t entry in the symcache hashtable, and it's being properly strdup'd so modname should still be live and not a dangling reference.

_Original issue: http://code.google.com/p/drmemory/issues/detail?id=821_