[compiler-rt][rtsan] Add scoped reporting lock

[cjappl]

From the ScopedReportingLock docstring:

// Lock sanitizer error reporting and protects against nested errors.

Uses a static lock to ensure multiple threads reporting issues at the same time don't have printing collisions. This isn't so important now, but will be with continue mode in the future.

[cjappl]

CC @davidtrevelyan

[llvmbot]

@llvm/pr-subscribers-compiler-rt-sanitizer

Author: Chris Apple (cjappl)

Changes

From the ScopedReportingLock docstring:

// Lock sanitizer error reporting and protects against nested errors.

Uses a static lock to ensure multiple threads reporting issues at the same time don't have printing collisions. This isn't so important now, but will be with continue mode in the future.

---

Full diff: https://github.com/llvm/llvm-project/pull/107167.diff

1 Files Affected:

• (modified) compiler-rt/lib/rtsan/rtsan_context.cpp (+2)

diff --git a/compiler-rt/lib/rtsan/rtsan_context.cpp b/compiler-rt/lib/rtsan/rtsan_context.cpp
index abeaa1e8483493..97f18dfbbcca8e 100644
--- a/compiler-rt/lib/rtsan/rtsan_context.cpp
+++ b/compiler-rt/lib/rtsan/rtsan_context.cpp
@@ -91,6 +91,8 @@ bool __rtsan::Context::IsBypassed() const { return bypass_depth_ > 0; }
 
 void __rtsan::PrintDiagnostics(const char *intercepted_function_name, uptr pc,
                                uptr bp) {
+  ScopedErrorReportLock l;
+
   fprintf(stderr,
           "Real-time violation: intercepted call to real-time unsafe function "
           "`%s` in real-time context! Stack trace:\n",