Remove page level mprotects

Freeing block mprotects on the page which it turn
may lead to application crash if linker subsequently
tries to modify another block on the page.

Bug: 14895266
Change-Id: I8ff7f5df467d7be184242de652032b3c84e24b76

1 files changed, 0 insertions, 12 deletions

diff --git a/linker/linker_allocator.cpp b/linker/linker_allocator.cpp
index 805844fc2..60ce1ea47 100644
--- a/linker/linker_allocator.cpp
+++ b/linker/linker_allocator.cpp
@@ -42,8 +42,6 @@ void LinkerBlockAllocator::init(size_t block_size) {
 void* LinkerBlockAllocator::alloc() {
   if (free_block_list_ == nullptr) {
     create_new_page();
-  } else {
-    protect_page(free_block_list_, PROT_READ | PROT_WRITE);
   }
 
   FreeBlockInfo* block_info = reinterpret_cast<FreeBlockInfo*>(free_block_list_);
@@ -82,10 +80,8 @@ void LinkerBlockAllocator::free(void* block) {
 
   FreeBlockInfo* block_info = reinterpret_cast<FreeBlockInfo*>(block);
 
-  protect_page(block_info, PROT_READ | PROT_WRITE);
   block_info->next_block = free_block_list_;
   block_info->num_free_blocks = 1;
-  protect_page(block_info, PROT_READ);
 
   free_block_list_ = block_info;
 }
@@ -98,14 +94,6 @@ void LinkerBlockAllocator::protect_all(int prot) {
   }
 }
 
-void LinkerBlockAllocator::protect_page(void* block, int prot) {
-  LinkerAllocatorPage* page = find_page(block);
-  if (page == nullptr || mprotect(page, PAGE_SIZE, prot) == -1) {
-    abort();
-  }
-}
-
-
 void LinkerBlockAllocator::create_new_page() {
   LinkerAllocatorPage* page = reinterpret_cast<LinkerAllocatorPage*>(mmap(nullptr, PAGE_SIZE,
       PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, 0, 0));