From fefb97a53606fad6060e217b9b642dbbd3a1e299 Mon Sep 17 00:00:00 2001 From: Jakub Jelinek Date: Tue, 15 Feb 2022 11:18:56 +0100 Subject: [PATCH] sanitizer: Use glibc _thread_db_sizeof_pthread symbol if present I've cherry-picked following fix from llvm-project. Recent glibcs have _thread_db_sizeof_pthread symbol variable which contains the size of struct pthread, so that sanitizers don't need to guess that and risk that it will change again. 2022-02-15 Jakub Jelinek * sanitizer_common/sanitizer_linux_libcdep.cpp: Cherry-pick llvm-project revision ef14b78d9a144ba81ba02083fe21eb286a88732b. (cherry picked from commit c4c0aa60891daeb4ea5a7c265bd681038f6d8271) --- .../sanitizer_linux_libcdep.cpp | 21 ++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) diff --git a/libsanitizer/sanitizer_common/sanitizer_linux_libcdep.cpp b/libsanitizer/sanitizer_common/sanitizer_linux_libcdep.cpp index e09d568d8024..7f7191b9c222 100644 --- a/libsanitizer/sanitizer_common/sanitizer_linux_libcdep.cpp +++ b/libsanitizer/sanitizer_common/sanitizer_linux_libcdep.cpp @@ -267,10 +267,8 @@ void InitTlsSize() { } // sizeof(struct pthread) from glibc. static atomic_uintptr_t thread_descriptor_size; -uptr ThreadDescriptorSize() { - uptr val = atomic_load_relaxed(&thread_descriptor_size); - if (val) - return val; +static uptr ThreadDescriptorSizeFallback() { + uptr val = 0; #if defined(__x86_64__) || defined(__i386__) || defined(__arm__) int major; int minor; @@ -310,8 +308,21 @@ uptr ThreadDescriptorSize() { #elif defined(__s390__) val = FIRST_32_SECOND_64(1152, 1776); // valid for glibc 2.22 #endif + return val; +} + +uptr ThreadDescriptorSize() { + uptr val = atomic_load_relaxed(&thread_descriptor_size); if (val) - atomic_store_relaxed(&thread_descriptor_size, val); + return val; + // _thread_db_sizeof_pthread is a GLIBC_PRIVATE symbol that is exported in + // glibc 2.34 and later. + if (unsigned *psizeof = static_cast( + dlsym(RTLD_DEFAULT, "_thread_db_sizeof_pthread"))) + val = *psizeof; + if (!val) + val = ThreadDescriptorSizeFallback(); + atomic_store_relaxed(&thread_descriptor_size, val); return val; } -- 2.47.2