[compiler-rt] 10f29a6 - [MSan] Fix wrong unpoison size in SignalAction (#144071)

[via llvm-commits]

Author: Kunqiu Chen
Date: 2025-06-18T14:53:33+08:00
New Revision: 10f29a607205c0c17ee9249a66feb63f0fdae182

URL: https://github.com/llvm/llvm-project/commit/10f29a607205c0c17ee9249a66feb63f0fdae182
DIFF: https://github.com/llvm/llvm-project/commit/10f29a607205c0c17ee9249a66feb63f0fdae182.diff

LOG: [MSan] Fix wrong unpoison size in SignalAction (#144071)

MSan should unpoison the parameters of extended signal handlers. 
However, MSan unpoisoned the second parameter with the wrong size 
`sizeof(__sanitizer_sigaction)`, inconsistent with its real type 
`siginfo_t`.

This commit fixes this issue by correcting the size to 
`sizeof(__sanitizer_siginfo)`.

Added: 
    

Modified: 
    compiler-rt/lib/msan/msan_interceptors.cpp

Removed: 
    


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diff  --git a/compiler-rt/lib/msan/msan_interceptors.cpp b/compiler-rt/lib/msan/msan_interceptors.cpp
index 76255cdb742a3..f94d3cb79aa00 100644
--- a/compiler-rt/lib/msan/msan_interceptors.cpp
+++ b/compiler-rt/lib/msan/msan_interceptors.cpp
@@ -1127,7 +1127,7 @@ static void SignalAction(int signo, void *si, void *uc) {
   SignalHandlerScope signal_handler_scope;
   ScopedThreadLocalStateBackup stlsb;
   UnpoisonParam(3);
-  __msan_unpoison(si, sizeof(__sanitizer_sigaction));
+  __msan_unpoison(si, sizeof(__sanitizer_siginfo));
   __msan_unpoison(uc, ucontext_t_sz(uc));
 
   typedef void (*sigaction_cb)(int, void *, void *);