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From 2969f5190561e26a8ce42d5dcda43ef59e0b6d32 Mon Sep 17 00:00:00 2001
From: liyancheng <412998149@qq.com>
Date: Tue, 26 Apr 2022 19:59:09 +0800
Subject: [PATCH] [Backport] sanitizer: Fix asan against glibc 2.34 [PR100114]

Reference: https://gcc.gnu.org/git/gitweb.cgi?p=gcc.git;h=d9f462fb372fb02da032cefd6b091d7582c425ae

sanitizer: Fix asan against glibc 2.34 [PR100114]

As mentioned in the PR, SIGSTKSZ is no longer a compile time constant in
glibc 2.34 and later, so
static const uptr kAltStackSize = SIGSTKSZ * 4;
needs dynamic initialization, but is used by a function called indirectly
from .preinit_array and therefore before the variable is constructed.
This results in using 0 size instead and all asan instrumented programs
die with:
==91==ERROR: AddressSanitizer failed to allocate 0x0 (0) bytes of SetAlternateSignalStack (error code: 22)

Here is a cherry-pick from upstream to fix this.

2021-04-17  Jakub Jelinek  <jakub@redhat.com>

PR sanitizer/100114
* sanitizer_common/sanitizer_posix_libcdep.cpp: Cherry-pick
llvm-project revisions 82150606fb11d28813ae6da1101f5bda638165fe
and b93629dd335ffee2fc4b9b619bf86c3f9e6b0023.
---
 .../sanitizer_common/sanitizer_posix_libcdep.cpp    | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/libsanitizer/sanitizer_common/sanitizer_posix_libcdep.cpp b/libsanitizer/sanitizer_common/sanitizer_posix_libcdep.cpp
index 304b3a01a..ac88fbe07 100644
--- a/libsanitizer/sanitizer_common/sanitizer_posix_libcdep.cpp
+++ b/libsanitizer/sanitizer_common/sanitizer_posix_libcdep.cpp
@@ -169,7 +169,11 @@ bool SupportsColoredOutput(fd_t fd) {
 
 #if !SANITIZER_GO
 // TODO(glider): different tools may require different altstack size.
-static const uptr kAltStackSize = SIGSTKSZ * 4;  // SIGSTKSZ is not enough.
+static uptr GetAltStackSize() {
+  // SIGSTKSZ is not enough.
+  static const uptr kAltStackSize = SIGSTKSZ * 4;
+  return kAltStackSize;
+}
 
 void SetAlternateSignalStack() {
   stack_t altstack, oldstack;
@@ -180,10 +184,9 @@ void SetAlternateSignalStack() {
   // TODO(glider): the mapped stack should have the MAP_STACK flag in the
   // future. It is not required by man 2 sigaltstack now (they're using
   // malloc()).
-  void* base = MmapOrDie(kAltStackSize, __func__);
-  altstack.ss_sp = (char*) base;
+  altstack.ss_size = GetAltStackSize();
+  altstack.ss_sp = (char *)MmapOrDie(altstack.ss_size, __func__);
   altstack.ss_flags = 0;
-  altstack.ss_size = kAltStackSize;
   CHECK_EQ(0, sigaltstack(&altstack, nullptr));
 }
 
@@ -191,7 +194,7 @@ void UnsetAlternateSignalStack() {
   stack_t altstack, oldstack;
   altstack.ss_sp = nullptr;
   altstack.ss_flags = SS_DISABLE;
-  altstack.ss_size = kAltStackSize;  // Some sane value required on Darwin.
+  altstack.ss_size = GetAltStackSize();  // Some sane value required on Darwin.
   CHECK_EQ(0, sigaltstack(&altstack, &oldstack));
   UnmapOrDie(oldstack.ss_sp, oldstack.ss_size);
 }
-- 
2.25.1