Author: David Peixotto Date: 2025-09-18T08:20:09-07:00 New Revision: 44a1f7e7cabebff853ccfbbb669f79673a2ec335
URL: https://github.com/llvm/llvm-project/commit/44a1f7e7cabebff853ccfbbb669f79673a2ec335 DIFF: https://github.com/llvm/llvm-project/commit/44a1f7e7cabebff853ccfbbb669f79673a2ec335.diff LOG: [lldb] Fix unsafe map mutation in ProcessElfCore::FindModuleUUID (#159444) The `ProcessElfCore::FindModuleUUID` function can be called by multiple threads at the same time when `target.parallel-module-load` is true. We were using the `operator[]` to lookup the UUID which will mutate the map when the key is not present. This is unsafe in a multi-threaded contex so we now use a read-only `find` operation and explicitly return an invalid UUID when the key is not present. The `m_uuids` map can follow a create-then-query pattern. It is populated in the `DoLoadCore` function which looks like it is only called in a single-threaded context so we do not need extra locking as long as we keep the other accesses read-only. Other fixes I considered * Use a lock to protect access - We don't need to modify the map after creation so we can allow concurrent read-only access. * Store the map in a const pointer container to prevent accidental mutation in other places. - Only accessed in one place currently so just added a comment. * Store the UUID in the NT_FILE_Entry after building the mapping correctly in `UpdateBuildIdForNTFileEntries`. - The map lets us avoid a linear search in `FindModuleUUID`. This commit also reverts the temporary workaround from #159395 which disabled parallel module loading to avoid the test failure. Fixes #159377 Added: Modified: lldb/source/Plugins/Process/elf-core/ProcessElfCore.cpp lldb/test/API/functionalities/postmortem/netbsd-core/TestNetBSDCore.py Removed: ################################################################################ diff --git a/lldb/source/Plugins/Process/elf-core/ProcessElfCore.cpp b/lldb/source/Plugins/Process/elf-core/ProcessElfCore.cpp index 38bf13543c617..b7029fb3a95b3 100644 --- a/lldb/source/Plugins/Process/elf-core/ProcessElfCore.cpp +++ b/lldb/source/Plugins/Process/elf-core/ProcessElfCore.cpp @@ -308,7 +308,13 @@ llvm::StringRef ProcessElfCore::GetMainExecutablePath() { } UUID ProcessElfCore::FindModuleUUID(const llvm::StringRef path) { - return m_uuids[std::string(path)]; + // Lookup the UUID for the given path in the map. + // Note that this could be called by multiple threads so make sure + // we access the map in a thread safe way (i.e. don't use operator[]). + auto it = m_uuids.find(std::string(path)); + if (it != m_uuids.end()) + return it->second; + return UUID(); } lldb_private::DynamicLoader *ProcessElfCore::GetDynamicLoader() { diff --git a/lldb/test/API/functionalities/postmortem/netbsd-core/TestNetBSDCore.py b/lldb/test/API/functionalities/postmortem/netbsd-core/TestNetBSDCore.py index 179dbdf88fa8a..ff1ef21e02e31 100644 --- a/lldb/test/API/functionalities/postmortem/netbsd-core/TestNetBSDCore.py +++ b/lldb/test/API/functionalities/postmortem/netbsd-core/TestNetBSDCore.py @@ -117,8 +117,6 @@ def check_backtrace(self, thread, filename, backtrace): ) def do_test(self, filename, pid, region_count): - # Temporary workaround for https://github.com/llvm/llvm-project/issues/159377 - self.runCmd("settings set target.parallel-module-load false") target = self.dbg.CreateTarget(filename) process = target.LoadCore(filename + ".core") _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
