On Thu, 22 Aug 2024 19:50:01 GMT, Alex Menkov <amen...@openjdk.org> wrote:
> On Windows SA agent gets a class vtable from symbols, exported from jvm.dll > (it exports symbols like "??_7" + type + "@@6B@"). > But symbol lookup function first requests WinDbg about the symbol. > Sometimes WinDbg routine IDebugSymbols::GetOffsetByName() returns offset for > both class and class pointer types. Returned offsets correspond to symbols > like "jvm!class_name::`vftable'". > The behavior is intermittent, I was not able to find what is the reason. > The fix adds workaround for the case - if GetOffsetByName succeeded, we check > if corresponding symbol contains requested one. > So it returns expected offset for non-vtable symbols like > "MaxJNILocalCapacity" (GetOffsetByName returns offset for > "jvm!MaxJNILocalCapacity"), but returns 0 for vtlb lookup. > > Additionally added check for results of > IDebugSymbols::SetImagePath/SetSymbolPath > > Testing: tier1,tier2,hs-tier5-svc Not an expert on this code by any means, but this seems a reasonable way to tackle the problem. Thanks. src/jdk.hotspot.agent/windows/native/libsaproc/sawindbg.cpp line 865: > 863: // As a workaround check if returned symbol contains requested symbol. > 864: ULONG64 disp = 0L; > 865: char buf[512]; s/512/SYMBOL_BUFSIZE/ ? ------------- Marked as reviewed by dholmes (Reviewer). PR Review: https://git.openjdk.org/jdk/pull/20684#pullrequestreview-2259468929 PR Review Comment: https://git.openjdk.org/jdk/pull/20684#discussion_r1730492007