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Mitigating VMMethod::id() crash #359

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Merged
zhengyu123 merged 2 commits into from
Feb 6, 2026
+12 −1
Merged

Mitigating VMMethod::id() crash #359

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1bbde31
Mitigating VMMethod::id() crash
zhengyu123 Feb 6, 2026
f934669
gtest
zhengyu123 Feb 6, 2026
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5 changes: 5 additions & 0 deletions ddprof-lib/src/main/cpp/safeAccess.h
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Original file line number Diff line number Diff line change
Expand Up @@ -73,6 +73,11 @@ class SafeAccess {

NOINLINE __attribute__((aligned(16)))
static void *loadPtr(void** ptr, void* default_value);

static inline bool isReadable(void* ptr) {
return load32((int32_t*)ptr, 1) != 1 ||
load32((int32_t*)ptr, -1) != -1;
}
};

#endif // _SAFEACCESS_H
2 changes: 1 addition & 1 deletion ddprof-lib/src/main/cpp/stackWalker.cpp
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Expand Up @@ -59,7 +59,7 @@ static inline void fillFrame(ASGCT_CallFrame& frame, FrameTypeId type, int bci,
}

static jmethodID getMethodId(VMMethod* method) {
if (!inDeadZone(method) && aligned((uintptr_t)method)) {
if (!inDeadZone(method) && aligned((uintptr_t)method) && SafeAccess::isReadable((void*)method)) {
return method->validatedId();
}
return NULL;
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6 changes: 6 additions & 0 deletions ddprof-lib/src/test/cpp/safefetch_ut.cpp
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Expand Up @@ -105,6 +105,12 @@ TEST_F(SafeFetchTest, invalidAccessPtr) {
EXPECT_EQ(res, bp);
}

TEST_F(SafeFetchTest, isReadable) {
char c = 'x';
EXPECT_TRUE(SafeAccess::isReadable(&c));
EXPECT_FALSE(SafeAccess::isReadable(nullptr));
}

/**
* Tests that safeFetch32 correctly handles mprotected memory.
*
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