Author: Jeremy Day Date: 2025-04-02T16:35:02-07:00 New Revision: be3abfc00f37d07c641b3e2f93eef5d1a446af8e
URL: https://github.com/llvm/llvm-project/commit/be3abfc00f37d07c641b3e2f93eef5d1a446af8e DIFF: https://github.com/llvm/llvm-project/commit/be3abfc00f37d07c641b3e2f93eef5d1a446af8e.diff LOG: [lldb] Clear thread name container before writing UTF8 bytes (#134150) `llvm::convertUTF16ToUTF8String` opens with an assertion that the output container is empty: https://github.com/llvm/llvm-project/blob/3bdf9a08804a5b424fd32fef3b0089f3a6db839d/llvm/lib/Support/ConvertUTFWrapper.cpp#L83-L84 It's not clear to me why this function requires the output container to be empty instead of just overwriting it, but the callsite in `TargetThreadWindows::GetName` may reuse the container without clearing it out first, resulting in an assertion failure: ``` # Child-SP RetAddr Call Site 00 000000d2`44b8ea48 00007ff8`beefc12e ntdll!NtTerminateProcess+0x14 01 000000d2`44b8ea50 00007ff8`bcf518ab ntdll!RtlExitUserProcess+0x11e 02 000000d2`44b8ea80 00007ff8`bc0e0143 KERNEL32!ExitProcessImplementation+0xb 03 000000d2`44b8eab0 00007ff8`bc0e4c49 ucrtbase!common_exit+0xc7 04 000000d2`44b8eb10 00007ff8`bc102ae6 ucrtbase!abort+0x69 05 000000d2`44b8eb40 00007ff8`bc102cc1 ucrtbase!common_assert_to_stderr<wchar_t>+0x6e 06 000000d2`44b8eb80 00007fff`b8e27a80 ucrtbase!wassert+0x71 07 000000d2`44b8ebb0 00007fff`b8b821e1 liblldb!llvm::convertUTF16ToUTF8String+0x30 [D:\r\_work\swift-build\swift-build\SourceCache\llvm-project\llvm\lib\Support\ConvertUTFWrapper.cpp @ 88] 08 000000d2`44b8ec30 00007fff`b83e9aa2 liblldb!lldb_private::TargetThreadWindows::GetName+0x1b1 [D:\r\_work\swift-build\swift-build\SourceCache\llvm-project\lldb\source\Plugins\Process\Windows\Common\TargetThreadWindows.cpp @ 198] 09 000000d2`44b8eca0 00007ff7`2a3c3c14 liblldb!lldb::SBThread::GetName+0x102 [D:\r\_work\swift-build\swift-build\SourceCache\llvm-project\lldb\source\API\SBThread.cpp @ 432] 0a 000000d2`44b8ed70 00007ff7`2a3a5ac6 lldb_dap!lldb_dap::CreateThread+0x1f4 [S:\SourceCache\llvm-project\lldb\tools\lldb-dap\JSONUtils.cpp @ 877] 0b 000000d2`44b8ef10 00007ff7`2a3b0ab5 lldb_dap!`anonymous namespace'::request_threads+0xa6 [S:\SourceCache\llvm-project\lldb\tools\lldb-dap\lldb-dap.cpp @ 3906] 0c 000000d2`44b8f010 00007ff7`2a3b0fe8 lldb_dap!lldb_dap::DAP::HandleObject+0x1c5 [S:\SourceCache\llvm-project\lldb\tools\lldb-dap\DAP.cpp @ 796] 0d 000000d2`44b8f130 00007ff7`2a3a8b96 lldb_dap!lldb_dap::DAP::Loop+0x78 [S:\SourceCache\llvm-project\lldb\tools\lldb-dap\DAP.cpp @ 812] 0e 000000d2`44b8f1d0 00007ff7`2a4b5fbc lldb_dap!main+0x1096 [S:\SourceCache\llvm-project\lldb\tools\lldb-dap\lldb-dap.cpp @ 5319] 0f (Inline Function) --------`-------- lldb_dap!invoke_main+0x22 [D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl @ 78] 10 000000d2`44b8fb80 00007ff8`bcf3e8d7 lldb_dap!__scrt_common_main_seh+0x10c [D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl @ 288] 11 000000d2`44b8fbc0 00007ff8`beefbf6c KERNEL32!BaseThreadInitThunk+0x17 12 000000d2`44b8fbf0 00000000`00000000 ntdll!RtlUserThreadStart+0x2c ``` This stack trace was captured from the lldb distributed in the Swift toolchain. The issue is easy to reproduce by resuming from a breakpoint twice in VS Code. I've verified that clearing out the container here fixes the assertion failure. Added: Modified: lldb/source/Plugins/Process/Windows/Common/TargetThreadWindows.cpp Removed: ################################################################################ diff --git a/lldb/source/Plugins/Process/Windows/Common/TargetThreadWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/TargetThreadWindows.cpp index a0d0f0ea0abc8..b2b66f2927644 100644 --- a/lldb/source/Plugins/Process/Windows/Common/TargetThreadWindows.cpp +++ b/lldb/source/Plugins/Process/Windows/Common/TargetThreadWindows.cpp @@ -192,6 +192,7 @@ const char *TargetThreadWindows::GetName() { if (SUCCEEDED(GetThreadDescription( m_host_thread.GetNativeThread().GetSystemHandle(), &pszThreadName))) { LLDB_LOGF(log, "GetThreadDescription: %ls", pszThreadName); + m_name.clear(); llvm::convertUTF16ToUTF8String( llvm::ArrayRef(reinterpret_cast<char *>(pszThreadName), wcslen(pszThreadName) * sizeof(wchar_t)), _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
