[compiler-rt] [memprof] Switch allocator to dynamic base address (PR #98510)

[Thurston Dang via llvm-commits]

https://github.com/thurstond created https://github.com/llvm/llvm-project/pull/98510

memprof_rtl.cpp calls InitializeShadowMemory() - which dynamically/"randomly" chooses a base address for the shadow mapping - prior to InitializeAllocator(). If we are unlucky, the shadow memory may be mapped in the same region where the allocator wants to be.

This patch fixes the issue by changing the allocator to dynamically choosing a base address, as suggested by Vitaly. For comparison, HWASan already dynamically chooses the base addresses for the shadow mapping and allocator.

The "unlucky" failure was observed on a new buildbot: https://lab.llvm.org/buildbot/#/builders/66/builds/1361/steps/17/logs/stdio

>From 81ed94aaf5f8ab385fbb1adbad8dd70dfb1267d6 Mon Sep 17 00:00:00 2001
From: Thurston Dang <thurston at google.com>
Date: Thu, 11 Jul 2024 17:55:39 +0000
Subject: [PATCH] [memprof] Switch allocator to dynamic base address

memprof_rtl.cpp calls InitializeShadowMemory() - which dynamically/"randomly" chooses a base address for the shadow mapping - prior to InitializeAllocator(). If we are unlucky, the shadow memory may be mapped in the same region where the allocator wants to be.

This patch fixes the issue by changing the allocator to dynamically choosing a base address, as suggested by Vitaly. For comparison, HWASan already dynamically chooses the base addresses for the shadow mapping and allocator.

The "unlucky" failure was observed on a new buildbot (https://lab.llvm.org/buildbot/#/builders/66/builds/1361/steps/17/logs/stdio).
---
 compiler-rt/lib/memprof/memprof_allocator.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compiler-rt/lib/memprof/memprof_allocator.h b/compiler-rt/lib/memprof/memprof_allocator.h
index 89e924f80d41a..ee8034b366b67 100644
--- a/compiler-rt/lib/memprof/memprof_allocator.h
+++ b/compiler-rt/lib/memprof/memprof_allocator.h
@@ -49,7 +49,7 @@ struct MemprofMapUnmapCallback {
 #if SANITIZER_APPLE
 constexpr uptr kAllocatorSpace = 0x600000000000ULL;
 #else
-constexpr uptr kAllocatorSpace = 0x500000000000ULL;
+constexpr uptr kAllocatorSpace = ~(uptr)0;
 #endif
 constexpr uptr kAllocatorSize = 0x40000000000ULL; // 4T.
 typedef DefaultSizeClassMap SizeClassMap;