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Fix use after free on ppc64le (rhbz#2283525)

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Related: RHEL-28670
This commit is contained in:
Konrad Kleine 2024-05-28 15:18:49 +02:00
parent fefbc99130
commit 54ffee6602
2 changed files with 110 additions and 1 deletions
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103
93442.patch Normal file
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@ -0,0 +1,103 @@
From 97ab1917845fa9426ba913139fc8a007cba1d7ce Mon Sep 17 00:00:00 2001
From: Nikita Popov <npopov@redhat.com>
Date: Mon, 27 May 2024 08:54:11 +0200
Subject: [PATCH] [PPCMergeStringPool] Only replace constant once (#92996)
In #88846 I changed this code to use RAUW to perform the replacement
instead of manual updates -- but kept the outer loop, which means we try
to perform RAUW once per user. However, some of the users might be freed
by the RAUW operation, resulting in use-after-free.
The case where this happens is constant users where the replacement
might result in the destruction of the original constant.
Fixes https://github.com/llvm/llvm-project/issues/92991.
(cherry picked from commit 9f85bc834b07ebfec9e5e02deb9255a0f6ec5cc7)
---
.../lib/Target/PowerPC/PPCMergeStringPool.cpp | 37 ++++---------------
.../PowerPC/mergeable-string-pool-pr92991.ll | 20 ++++++++++
2 files changed, 27 insertions(+), 30 deletions(-)
create mode 100644 llvm/test/CodeGen/PowerPC/mergeable-string-pool-pr92991.ll
diff --git a/llvm/lib/Target/PowerPC/PPCMergeStringPool.cpp b/llvm/lib/Target/PowerPC/PPCMergeStringPool.cpp
index ebd876d50c44e..0830b02370cd0 100644
--- a/llvm/lib/Target/PowerPC/PPCMergeStringPool.cpp
+++ b/llvm/lib/Target/PowerPC/PPCMergeStringPool.cpp
@@ -290,13 +290,6 @@ bool PPCMergeStringPool::mergeModuleStringPool(Module &M) {
return true;
}
-static bool userHasOperand(User *TheUser, GlobalVariable *GVOperand) {
- for (Value *Op : TheUser->operands())
- if (Op == GVOperand)
- return true;
- return false;
-}
-
// For pooled strings we need to add the offset into the pool for each string.
// This is done by adding a Get Element Pointer (GEP) before each user. This
// function adds the GEP.
@@ -307,29 +300,13 @@ void PPCMergeStringPool::replaceUsesWithGEP(GlobalVariable *GlobalToReplace,
Indices.push_back(ConstantInt::get(Type::getInt32Ty(*Context), 0));
Indices.push_back(ConstantInt::get(Type::getInt32Ty(*Context), ElementIndex));
- // Need to save a temporary copy of each user list because we remove uses
- // as we replace them.
- SmallVector<User *> Users;
- for (User *CurrentUser : GlobalToReplace->users())
- Users.push_back(CurrentUser);
-
- for (User *CurrentUser : Users) {
- // The user was not found so it must have been replaced earlier.
- if (!userHasOperand(CurrentUser, GlobalToReplace))
- continue;
-
- // We cannot replace operands in globals so we ignore those.
- if (isa<GlobalValue>(CurrentUser))
- continue;
-
- Constant *ConstGEP = ConstantExpr::getInBoundsGetElementPtr(
- PooledStructType, GPool, Indices);
- LLVM_DEBUG(dbgs() << "Replacing this global:\n");
- LLVM_DEBUG(GlobalToReplace->dump());
- LLVM_DEBUG(dbgs() << "with this:\n");
- LLVM_DEBUG(ConstGEP->dump());
- GlobalToReplace->replaceAllUsesWith(ConstGEP);
- }
+ Constant *ConstGEP =
+ ConstantExpr::getInBoundsGetElementPtr(PooledStructType, GPool, Indices);
+ LLVM_DEBUG(dbgs() << "Replacing this global:\n");
+ LLVM_DEBUG(GlobalToReplace->dump());
+ LLVM_DEBUG(dbgs() << "with this:\n");
+ LLVM_DEBUG(ConstGEP->dump());
+ GlobalToReplace->replaceAllUsesWith(ConstGEP);
}
} // namespace
diff --git a/llvm/test/CodeGen/PowerPC/mergeable-string-pool-pr92991.ll b/llvm/test/CodeGen/PowerPC/mergeable-string-pool-pr92991.ll
new file mode 100644
index 0000000000000..4e9c69e5fe4cf
--- /dev/null
+++ b/llvm/test/CodeGen/PowerPC/mergeable-string-pool-pr92991.ll
@@ -0,0 +1,20 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+; RUN: llc -mtriple=powerpc64le-unknown-linux-gnu < %s | FileCheck %s
+
+@g = private constant [4 x i32] [i32 122, i32 67, i32 35, i32 56]
+@g2 = private constant [1 x i64] [i64 1], align 8
+
+define void @test(ptr %p, ptr %p2) {
+; CHECK-LABEL: test:
+; CHECK: # %bb.0:
+; CHECK-NEXT: addis 5, 2, .L__ModuleStringPool@toc@ha
+; CHECK-NEXT: addi 5, 5, .L__ModuleStringPool@toc@l
+; CHECK-NEXT: addi 6, 5, 12
+; CHECK-NEXT: std 6, 0(3)
+; CHECK-NEXT: addi 3, 5, 16
+; CHECK-NEXT: std 3, 0(4)
+; CHECK-NEXT: blr
+ store ptr getelementptr inbounds ([4 x i32], ptr @g, i64 0, i64 1), ptr %p
+ store ptr getelementptr inbounds ([4 x i32], ptr @g, i64 0, i64 2), ptr %p2
+ ret void
+}

8
llvm.spec
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@ -101,7 +101,7 @@
Name: %{pkg_name} Name: %{pkg_name}
Version: %{maj_ver}.%{min_ver}.%{patch_ver}%{?rc_ver:~rc%{rc_ver}}%{?llvm_snapshot_version_suffix:~%{llvm_snapshot_version_suffix}} Version: %{maj_ver}.%{min_ver}.%{patch_ver}%{?rc_ver:~rc%{rc_ver}}%{?llvm_snapshot_version_suffix:~%{llvm_snapshot_version_suffix}}
Release: 2%{?dist} Release: 3%{?dist}
Summary: The Low Level Virtual Machine Summary: The Low Level Virtual Machine
License: Apache-2.0 WITH LLVM-exception OR NCSA License: Apache-2.0 WITH LLVM-exception OR NCSA
@ -129,6 +129,9 @@ Source8: https://github.com/llvm/llvm-project/releases/download/llvmorg-%{compat
# RHEL-specific patch to avoid unwanted python3-myst-parser dep # RHEL-specific patch to avoid unwanted python3-myst-parser dep
Patch101: 0101-Deactivate-markdown-doc.patch Patch101: 0101-Deactivate-markdown-doc.patch
# Backport of PPCMergeStringPool fix for rhbz#2283525.
Patch102: 93442.patch
BuildRequires: gcc BuildRequires: gcc
BuildRequires: gcc-c++ BuildRequires: gcc-c++
BuildRequires: clang BuildRequires: clang
@ -650,6 +653,9 @@ fi
%license LICENSE.TXT %license LICENSE.TXT
%changelog %changelog
* Tue May 28 2024 Nikita Popov <npopov@redhat.com> - 18.1.6-3
- Fix use after free on ppc64le (rhbz#2283525)
* Wed May 22 2024 Konrad Kleine <kkleine@redhat.com> - 18.1.6-2 * Wed May 22 2024 Konrad Kleine <kkleine@redhat.com> - 18.1.6-2
- Turn on build condition bundle_compat_lib by default - Turn on build condition bundle_compat_lib by default