Bug 164925 – [GTK] Crash in WebCore::TextureMapperTiledBackingStore::createOrDestroyTilesIfNeeded allocating too-large vector

• Status: NEW
• Component: WebKitGTK

[Michael Catanzaro]

Only two reports of this one. Web process crash in WebCore::TextureMapperTiledBackingStore::createOrDestroyTilesIfNeeded inside WTF::Vector<WebCore::FloatRect, 0ul, WTF::CrashOnOverflow, 16ul>::expandCapacity. It's crashing on overflow here:

        if (newCapacity > std::numeric_limits<unsigned>::max() / sizeof(T))
            CRASH();

Curiously, the function accepts a size_t newCapacity parameter, but the limit it's checking is for smaller unsigned int.

Long backtrace downstream. Short version:

Thread 1 (Thread 0x7fa365b88ac0 (LWP 25221)):
#0  0x00007fa36318a67c in WTFCrash() () at /usr/src/debug/webkitgtk-2.12.4/Source/WTF/wtf/Assertions.cpp:322
#1  0x00007fa363a91df6 in WTF::Vector<WebCore::FloatRect, 0ul, WTF::CrashOnOverflow, 16ul>::expandCapacity(unsigned long) (newCapacity=<optimized out>, this=0x7ffdaef91720) at /usr/src/debug/webkitgtk-2.12.4/Source/WTF/wtf/Vector.h:266
        sizeToAllocate = <optimized out>
        this = 0x7ffdaef91720
#2  0x00007fa363a91df6 in WTF::Vector<WebCore::FloatRect, 0ul, WTF::CrashOnOverflow, 16ul>::expandCapacity(unsigned long) (newCapacity=<optimized out>, this=0x7ffdaef91720) at /usr/src/debug/webkitgtk-2.12.4/Source/WTF/wtf/Vector.h:1094
        this = 0x7ffdaef91720
#3  0x00007fa363a91df6 in WTF::Vector<WebCore::FloatRect, 0ul, WTF::CrashOnOverflow, 16ul>::expandCapacity(unsigned long) (this=0x7ffdaef91720, newMinCapacity=<optimized out>) at /usr/src/debug/webkitgtk-2.12.4/Source/WTF/wtf/Vector.h:955
#4  0x00007fa364a58100 in WebCore::TextureMapperTiledBackingStore::createOrDestroyTilesIfNeeded(WebCore::FloatSize const&, WebCore::IntSize const&, bool) (ptr=0x7ffdaef91740, newMinCapacity=<optimized out>, this=0x7ffdaef91720) at /usr/src/debug/webkitgtk-2.12.4/Source/WTF/wtf/Vector.h:962
        index = <optimized out>
        tileRect = {m_location = {m_x = 3690000, m_y = 26344000}, m_size = {m_width = 2000, m_height = 2000}}
        x = <optimized out>
        y = 26344000
        scaledSize = {m_width = 33554432, m_height = 33554432}
        tileRectsToAdd = {<WTF::VectorBuffer<WebCore::FloatRect, 0ul>> = {<WTF::VectorBufferBase<WebCore::FloatRect>> = {m_buffer = 0x7f9e69800000, m_capacity = 221001661, m_size = 221001661}, <No data fields>}, <No data fields>}
        tileIndicesToRemove = {<WTF::VectorBuffer<int, 0ul>> = {<WTF::VectorBufferBase<int>> = {m_buffer = 0x0, m_capacity = 0, m_size = 0}, <No data fields>}, <No data fields>}
        hasAlpha = <optimized out>
        tileSize = @0x7ffdaef917d0: {m_width = 2000, m_height = 2000}
        size = <optimized out>
        this = 0x7fa29e59e780

[Carlos Garcia Campos]

We don't even use TextureMapperTiledBackingStore anymore since 2.14. Well only when building without coord graphics.