[llvm-branch-commits] [compiler-rt] 2cb08db - [compiler-rt][sanitizer] fix msghdr for musl (#136195)

[Douglas Yung via llvm-branch-commits]

Author: Deák Lajos
Date: 2025-10-06T06:41:25Z
New Revision: 2cb08dbb39b17c4936cc604c9ca11a3f0f9d23c5

URL: https://github.com/llvm/llvm-project/commit/2cb08dbb39b17c4936cc604c9ca11a3f0f9d23c5
DIFF: https://github.com/llvm/llvm-project/commit/2cb08dbb39b17c4936cc604c9ca11a3f0f9d23c5.diff

LOG: [compiler-rt][sanitizer] fix msghdr for musl (#136195)

Ran into the issue on Alpine when building with TSAN that
`__sanitizer_msghdr` and the `msghdr` provided by musl did not match.
This caused lots of tsan reports and an eventual termination of the
application by the oom during a `sendmsg`.

Added: 
    

Modified: 
    compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.h

Removed: 
    


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diff  --git a/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.h b/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.h
index f118d53f0df80..24966523f3a02 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.h
@@ -478,6 +478,30 @@ struct __sanitizer_cmsghdr {
   int cmsg_level;
   int cmsg_type;
 };
+#  elif SANITIZER_MUSL
+struct __sanitizer_msghdr {
+  void *msg_name;
+  unsigned msg_namelen;
+  struct __sanitizer_iovec *msg_iov;
+  int msg_iovlen;
+#    if SANITIZER_WORDSIZE == 64
+  int __pad1;
+#    endif
+  void *msg_control;
+  unsigned msg_controllen;
+#    if SANITIZER_WORDSIZE == 64
+  int __pad2;
+#    endif
+  int msg_flags;
+};
+struct __sanitizer_cmsghdr {
+  unsigned cmsg_len;
+#    if SANITIZER_WORDSIZE == 64
+  int __pad1;
+#    endif
+  int cmsg_level;
+  int cmsg_type;
+};
 #  else
 // In POSIX, int msg_iovlen; socklen_t msg_controllen; socklen_t cmsg_len; but
 // many implementations don't conform to the standard.