[compiler-rt] [scudo] Add hooks to mark the range of realloc (PR #73883)
via llvm-commits
llvm-commits at lists.llvm.org
Wed Nov 29 17:07:22 PST 2023
https://github.com/ChiaHungDuan updated https://github.com/llvm/llvm-project/pull/73883
>From aadc2730c4d2627dc9b072cf1696ab607b9cb4f3 Mon Sep 17 00:00:00 2001
From: Chia-hung Duan <chiahungduan at google.com>
Date: Wed, 29 Nov 2023 23:53:32 +0000
Subject: [PATCH 1/2] [scudo] Add hooks to mark the range of realloc
`realloc` may involve both allocation and deallocation. Given that the
reporting the events is not atomic and which may lead the hook user to a
false case that the double-use pattern happens. In general, this can be
resolved on the hook side. To alleviate the task of handling it, we add
two new hooks to mark the range and reorder the reporting.
---
compiler-rt/lib/scudo/standalone/combined.h | 11 +++-
.../standalone/include/scudo/interface.h | 7 +-
.../standalone/tests/wrappers_c_test.cpp | 42 ++++++++++--
.../lib/scudo/standalone/wrappers_c.inc | 65 ++++++++++++++-----
4 files changed, 100 insertions(+), 25 deletions(-)
diff --git a/compiler-rt/lib/scudo/standalone/combined.h b/compiler-rt/lib/scudo/standalone/combined.h
index b1700e5ecef7f5b..0a7d6492e1194ab 100644
--- a/compiler-rt/lib/scudo/standalone/combined.h
+++ b/compiler-rt/lib/scudo/standalone/combined.h
@@ -827,10 +827,15 @@ class Allocator {
// for it, which then forces realloc to copy the usable size of a chunk as
// opposed to its actual size.
uptr getUsableSize(const void *Ptr) {
- initThreadMaybe();
if (UNLIKELY(!Ptr))
return 0;
+ return getAllocSize(Ptr);
+ }
+
+ uptr getAllocSize(const void *Ptr) {
+ initThreadMaybe();
+
#ifdef GWP_ASAN_HOOKS
if (UNLIKELY(GuardedAlloc.pointerIsMine(Ptr)))
return GuardedAlloc.getSize(Ptr);
@@ -839,9 +844,11 @@ class Allocator {
Ptr = getHeaderTaggedPointer(const_cast<void *>(Ptr));
Chunk::UnpackedHeader Header;
Chunk::loadHeader(Cookie, Ptr, &Header);
- // Getting the usable size of a chunk only makes sense if it's allocated.
+
+ // Getting the alloc size of a chunk only makes sense if it's allocated.
if (UNLIKELY(Header.State != Chunk::State::Allocated))
reportInvalidChunkState(AllocatorAction::Sizing, const_cast<void *>(Ptr));
+
return getSize(Ptr, &Header);
}
diff --git a/compiler-rt/lib/scudo/standalone/include/scudo/interface.h b/compiler-rt/lib/scudo/standalone/include/scudo/interface.h
index 6c0c521f8d82f85..e4534fc9ec2f721 100644
--- a/compiler-rt/lib/scudo/standalone/include/scudo/interface.h
+++ b/compiler-rt/lib/scudo/standalone/include/scudo/interface.h
@@ -17,10 +17,15 @@ extern "C" {
__attribute__((weak)) const char *__scudo_default_options(void);
// Post-allocation & pre-deallocation hooks.
-// They must be thread-safe and not use heap related functions.
__attribute__((weak)) void __scudo_allocate_hook(void *ptr, size_t size);
__attribute__((weak)) void __scudo_deallocate_hook(void *ptr);
+// These hooks are used to mark the scope of doing realloc(). Note that the
+// allocation/deallocation are still reported through the hooks above, this is
+// only used when you want to group two operations in the realloc().
+__attribute__((weak)) void __scudo_realloc_begin_hook(void *old_ptr);
+__attribute__((weak)) void __scudo_realloc_end_hook(void *old_ptr);
+
void __scudo_print_stats(void);
typedef void (*iterate_callback)(uintptr_t base, size_t size, void *arg);
diff --git a/compiler-rt/lib/scudo/standalone/tests/wrappers_c_test.cpp b/compiler-rt/lib/scudo/standalone/tests/wrappers_c_test.cpp
index 623550535b6c8e2..7b47c872ae88d71 100644
--- a/compiler-rt/lib/scudo/standalone/tests/wrappers_c_test.cpp
+++ b/compiler-rt/lib/scudo/standalone/tests/wrappers_c_test.cpp
@@ -61,8 +61,13 @@ struct AllocContext {
struct DeallocContext {
void *Ptr;
};
+struct ReallocContext {
+ void *Begin;
+ void *End;
+};
static AllocContext AC;
static DeallocContext DC;
+static ReallocContext RC;
#if (SCUDO_ENABLE_HOOKS_TESTS == 1)
__attribute__((visibility("default"))) void __scudo_allocate_hook(void *Ptr,
@@ -73,6 +78,14 @@ __attribute__((visibility("default"))) void __scudo_allocate_hook(void *Ptr,
__attribute__((visibility("default"))) void __scudo_deallocate_hook(void *Ptr) {
DC.Ptr = Ptr;
}
+__attribute__((visibility("default"))) void
+__scudo_realloc_begin_hook(void *Ptr) {
+ RC.Begin = Ptr;
+}
+__attribute__((visibility("default"))) void
+__scudo_realloc_end_hook(void *Ptr) {
+ RC.End = Ptr;
+}
#endif // (SCUDO_ENABLE_HOOKS_TESTS == 1)
}
@@ -83,9 +96,12 @@ class ScudoWrappersCTest : public Test {
printf("Hooks are enabled but hooks tests are disabled.\n");
}
- void invalidateAllocHookPtrAs(UNUSED void *Ptr) {
- if (SCUDO_ENABLE_HOOKS_TESTS)
+ void invalidateHookPtrsAs(UNUSED void *Ptr) {
+ if (SCUDO_ENABLE_HOOKS_TESTS) {
AC.Ptr = Ptr;
+ DC.Ptr = Ptr;
+ RC.Begin = RC.End = Ptr;
+ }
}
void verifyAllocHookPtr(UNUSED void *Ptr) {
if (SCUDO_ENABLE_HOOKS_TESTS)
@@ -99,6 +115,12 @@ class ScudoWrappersCTest : public Test {
if (SCUDO_ENABLE_HOOKS_TESTS)
EXPECT_EQ(Ptr, DC.Ptr);
}
+ void verifyReallocHooksScope(UNUSED void *Ptr) {
+ if (SCUDO_ENABLE_HOOKS_TESTS) {
+ EXPECT_EQ(Ptr, RC.Begin);
+ EXPECT_EQ(Ptr, RC.End);
+ }
+ }
};
using ScudoWrappersCDeathTest = ScudoWrappersCTest;
@@ -258,26 +280,30 @@ TEST_F(ScudoWrappersCTest, AlignedAlloc) {
}
TEST_F(ScudoWrappersCDeathTest, Realloc) {
+ invalidateHookPtrsAs(reinterpret_cast<void *>(0xdeadbeef));
// realloc(nullptr, N) is malloc(N)
void *P = realloc(nullptr, Size);
EXPECT_NE(P, nullptr);
verifyAllocHookPtr(P);
verifyAllocHookSize(Size);
+ verifyReallocHooksScope(nullptr);
free(P);
verifyDeallocHookPtr(P);
+ invalidateHookPtrsAs(reinterpret_cast<void *>(0xdeadbeef));
P = malloc(Size);
EXPECT_NE(P, nullptr);
// realloc(P, 0U) is free(P) and returns nullptr
EXPECT_EQ(realloc(P, 0U), nullptr);
verifyDeallocHookPtr(P);
+ verifyReallocHooksScope(P);
P = malloc(Size);
EXPECT_NE(P, nullptr);
EXPECT_LE(Size, malloc_usable_size(P));
memset(P, 0x42, Size);
- invalidateAllocHookPtrAs(reinterpret_cast<void *>(0xdeadbeef));
+ invalidateHookPtrsAs(reinterpret_cast<void *>(0xdeadbeef));
void *OldP = P;
P = realloc(P, Size * 2U);
EXPECT_NE(P, nullptr);
@@ -285,14 +311,16 @@ TEST_F(ScudoWrappersCDeathTest, Realloc) {
for (size_t I = 0; I < Size; I++)
EXPECT_EQ(0x42, (reinterpret_cast<uint8_t *>(P))[I]);
if (OldP == P) {
- verifyAllocHookPtr(reinterpret_cast<void *>(0xdeadbeef));
+ verifyDeallocHookPtr(OldP);
+ verifyAllocHookPtr(OldP);
} else {
verifyAllocHookPtr(P);
verifyAllocHookSize(Size * 2U);
verifyDeallocHookPtr(OldP);
}
+ verifyReallocHooksScope(OldP);
- invalidateAllocHookPtrAs(reinterpret_cast<void *>(0xdeadbeef));
+ invalidateHookPtrsAs(reinterpret_cast<void *>(0xdeadbeef));
OldP = P;
P = realloc(P, Size / 2U);
EXPECT_NE(P, nullptr);
@@ -300,11 +328,13 @@ TEST_F(ScudoWrappersCDeathTest, Realloc) {
for (size_t I = 0; I < Size / 2U; I++)
EXPECT_EQ(0x42, (reinterpret_cast<uint8_t *>(P))[I]);
if (OldP == P) {
- verifyAllocHookPtr(reinterpret_cast<void *>(0xdeadbeef));
+ verifyDeallocHookPtr(OldP);
+ verifyAllocHookPtr(OldP);
} else {
verifyAllocHookPtr(P);
verifyAllocHookSize(Size / 2U);
}
+ verifyReallocHooksScope(OldP);
free(P);
EXPECT_DEATH(P = realloc(P, Size), "");
diff --git a/compiler-rt/lib/scudo/standalone/wrappers_c.inc b/compiler-rt/lib/scudo/standalone/wrappers_c.inc
index e213da73393b5da..fde459bf5bca631 100644
--- a/compiler-rt/lib/scudo/standalone/wrappers_c.inc
+++ b/compiler-rt/lib/scudo/standalone/wrappers_c.inc
@@ -27,6 +27,51 @@ static void reportDeallocation(void *ptr) {
if (__scudo_deallocate_hook)
__scudo_deallocate_hook(ptr);
}
+static void reportReallocBegin(void *old_ptr) {
+ if (SCUDO_ENABLE_HOOKS)
+ if (__scudo_realloc_begin_hook)
+ __scudo_realloc_begin_hook(old_ptr);
+}
+static void reportReallocEnd(void *old_ptr) {
+ if (SCUDO_ENABLE_HOOKS)
+ if (__scudo_realloc_end_hook)
+ __scudo_realloc_end_hook(old_ptr);
+}
+
+static void *reallocImpl(void *ptr, size_t size) {
+ if (!ptr) {
+ void *Ptr = SCUDO_ALLOCATOR.allocate(size, scudo::Chunk::Origin::Malloc,
+ SCUDO_MALLOC_ALIGNMENT);
+ reportAllocation(Ptr, size);
+ return Ptr;
+ }
+ if (size == 0) {
+ reportDeallocation(ptr);
+ SCUDO_ALLOCATOR.deallocate(ptr, scudo::Chunk::Origin::Malloc);
+ return nullptr;
+ }
+
+ // Given that the reporting of deallocation and allocation are not atomic, we
+ // always pretend the old pointer will be released so that the user don't need
+ // to worry about the false double-use case from the view of hooks.
+ // For example, before the reporting all the events in the `realloc` has
+ // finished, another thread may have got the pointer released by the
+ // `realloc` and report it to the hook. It may be misinterpreted as double-use
+ // if it's not handled properly on the hook side.
+ reportDeallocation(ptr);
+ void *NewPtr = SCUDO_ALLOCATOR.reallocate(ptr, size, SCUDO_MALLOC_ALIGNMENT);
+ if (NewPtr != nullptr) {
+ // Note that even if NewPtr == ptr, the size has changed. We still need to
+ // report the new size.
+ reportAllocation(NewPtr, size);
+ } else {
+ // If `realloc` fails, the old pointer is not released. Report the old
+ // pointer as allocated.
+ reportAllocation(ptr, SCUDO_ALLOCATOR.getAllocSize(ptr));
+ }
+
+ return NewPtr;
+}
extern "C" {
@@ -163,23 +208,11 @@ INTERFACE WEAK void *SCUDO_PREFIX(pvalloc)(size_t size) {
}
INTERFACE WEAK void *SCUDO_PREFIX(realloc)(void *ptr, size_t size) {
- if (!ptr) {
- void *Ptr = SCUDO_ALLOCATOR.allocate(size, scudo::Chunk::Origin::Malloc,
- SCUDO_MALLOC_ALIGNMENT);
- reportAllocation(Ptr, size);
- return scudo::setErrnoOnNull(Ptr);
- }
- if (size == 0) {
- reportDeallocation(ptr);
- SCUDO_ALLOCATOR.deallocate(ptr, scudo::Chunk::Origin::Malloc);
- return nullptr;
- }
+ reportReallocBegin(ptr);
- void *NewPtr = SCUDO_ALLOCATOR.reallocate(ptr, size, SCUDO_MALLOC_ALIGNMENT);
- if (NewPtr != ptr) {
- reportAllocation(NewPtr, size);
- reportDeallocation(ptr);
- }
+ void *NewPtr = reallocImpl(ptr, size);
+
+ reportReallocEnd(ptr);
return scudo::setErrnoOnNull(NewPtr);
}
>From 4f7794e2e69680d71073a125528a4753fcf2ea24 Mon Sep 17 00:00:00 2001
From: Chia-hung Duan <chiahungduan at google.com>
Date: Thu, 30 Nov 2023 01:07:09 +0000
Subject: [PATCH 2/2] fixup! [scudo] Add hooks to mark the range of realloc
---
.../scudo/standalone/tests/wrappers_c_test.cpp | 17 +++++++++--------
compiler-rt/lib/scudo/standalone/wrappers_c.inc | 2 +-
2 files changed, 10 insertions(+), 9 deletions(-)
diff --git a/compiler-rt/lib/scudo/standalone/tests/wrappers_c_test.cpp b/compiler-rt/lib/scudo/standalone/tests/wrappers_c_test.cpp
index 7b47c872ae88d71..d68871fbf6a58d5 100644
--- a/compiler-rt/lib/scudo/standalone/tests/wrappers_c_test.cpp
+++ b/compiler-rt/lib/scudo/standalone/tests/wrappers_c_test.cpp
@@ -96,11 +96,12 @@ class ScudoWrappersCTest : public Test {
printf("Hooks are enabled but hooks tests are disabled.\n");
}
- void invalidateHookPtrsAs(UNUSED void *Ptr) {
+ void invalidateHookPtrs() {
if (SCUDO_ENABLE_HOOKS_TESTS) {
- AC.Ptr = Ptr;
- DC.Ptr = Ptr;
- RC.Begin = RC.End = Ptr;
+ void *InvalidPtr = reinterpret_cast<void *>(0xdeadbeef);
+ AC.Ptr = InvalidPtr;
+ DC.Ptr = InvalidPtr;
+ RC.Begin = RC.End = InvalidPtr;
}
}
void verifyAllocHookPtr(UNUSED void *Ptr) {
@@ -280,7 +281,7 @@ TEST_F(ScudoWrappersCTest, AlignedAlloc) {
}
TEST_F(ScudoWrappersCDeathTest, Realloc) {
- invalidateHookPtrsAs(reinterpret_cast<void *>(0xdeadbeef));
+ invalidateHookPtrs();
// realloc(nullptr, N) is malloc(N)
void *P = realloc(nullptr, Size);
EXPECT_NE(P, nullptr);
@@ -290,7 +291,7 @@ TEST_F(ScudoWrappersCDeathTest, Realloc) {
free(P);
verifyDeallocHookPtr(P);
- invalidateHookPtrsAs(reinterpret_cast<void *>(0xdeadbeef));
+ invalidateHookPtrs();
P = malloc(Size);
EXPECT_NE(P, nullptr);
// realloc(P, 0U) is free(P) and returns nullptr
@@ -303,7 +304,7 @@ TEST_F(ScudoWrappersCDeathTest, Realloc) {
EXPECT_LE(Size, malloc_usable_size(P));
memset(P, 0x42, Size);
- invalidateHookPtrsAs(reinterpret_cast<void *>(0xdeadbeef));
+ invalidateHookPtrs();
void *OldP = P;
P = realloc(P, Size * 2U);
EXPECT_NE(P, nullptr);
@@ -320,7 +321,7 @@ TEST_F(ScudoWrappersCDeathTest, Realloc) {
}
verifyReallocHooksScope(OldP);
- invalidateHookPtrsAs(reinterpret_cast<void *>(0xdeadbeef));
+ invalidateHookPtrs();
OldP = P;
P = realloc(P, Size / 2U);
EXPECT_NE(P, nullptr);
diff --git a/compiler-rt/lib/scudo/standalone/wrappers_c.inc b/compiler-rt/lib/scudo/standalone/wrappers_c.inc
index fde459bf5bca631..15d7c740dc4b3e2 100644
--- a/compiler-rt/lib/scudo/standalone/wrappers_c.inc
+++ b/compiler-rt/lib/scudo/standalone/wrappers_c.inc
@@ -66,7 +66,7 @@ static void *reallocImpl(void *ptr, size_t size) {
reportAllocation(NewPtr, size);
} else {
// If `realloc` fails, the old pointer is not released. Report the old
- // pointer as allocated.
+ // pointer as allocated back.
reportAllocation(ptr, SCUDO_ALLOCATOR.getAllocSize(ptr));
}
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