https://github.com/charles-zablit created https://github.com/llvm/llvm-project/pull/221697
`g_watchme` was declared right next to `g_sigusr1_count`. Hardware watchpoints round the watched address to an alignment boundary, so a watchpoint on `g_watchme` could also end up covering `g_sigusr1_count`. When the signal thread's handler touches `g_sigusr1_count` while the watchpoint threads write `g_watchme`, that overlap causes a spurious hit and lldb can attribute the stop to the wrong thread. See llvm.org/PR35228. Fix: align `g_watchme` and pad after it so it can't share a watchpoint's range with another global. Assisted by Claude. >From 347f84e86e0b63da16669cfcf7d9a49df367b55f Mon Sep 17 00:00:00 2001 From: Charles Zablit <[email protected]> Date: Mon, 7 Sep 2026 12:36:49 +0200 Subject: [PATCH] [lldb] Isolate g_watchme in memory to fix flaky TestConcurrentTwoWatchpointsOneSignal --- .../API/functionalities/thread/concurrent_events/main.cpp | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/lldb/test/API/functionalities/thread/concurrent_events/main.cpp b/lldb/test/API/functionalities/thread/concurrent_events/main.cpp index 84d8c7015a796..ba4ab62d3fca9 100644 --- a/lldb/test/API/functionalities/thread/concurrent_events/main.cpp +++ b/lldb/test/API/functionalities/thread/concurrent_events/main.cpp @@ -19,7 +19,9 @@ typedef std::vector<pthread_t> thread_vector; pseudo_barrier_t g_barrier; int g_breakpoint = 0; int g_sigusr1_count = 0; -uint32_t g_watchme; + +alignas(16) uint32_t g_watchme; +uint32_t g_watchme_padding[4]; struct action_args { int delay; _______________________________________________ lldb-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
