https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71291
--- Comment #10 from Maxim Ostapenko <m.ostapenko at samsung dot com> ---
I've build Firefox locally with clang with optimizations disabled
(CFLAGS="-fsanitize=address -fsanitize-recover=address -O0") and got pretty the
same backtrace:
==12707==ERROR: AddressSanitizer: stack-buffer-underflow on address
0x7fe22dbc417c at pc 0x7fe25e3b9ee5 bp 0x7fe22dbc40b0 sp 0x7fe22dbc40a8
READ of size 4 at 0x7fe22dbc417c thread T39 (Compositor)
#0 0x7fe25e3b9ee4 in mozilla::gfx::BasePoint4D<float,
mozilla::gfx::Point4DTyped<mozilla::gfx::UnknownUnits, float>
>::DotProduct(mozilla::gfx::Point4DTyped<mozilla::gfx::UnknownUnits, float>
const&) const /home/max/src/firefox/gfx/2d/BasePoint4D.h:101:68
#1 0x7fe25e3b7e6e in unsigned long
mozilla::gfx::Matrix4x4Typed<mozilla::gfx::UnknownUnits,
mozilla::gfx::UnknownUnits>::TransformAndClipRect<float>(mozilla::gfx::RectTyped<mozilla::gfx::UnknownUnits,
float> const&, mozilla::gfx::RectTyped<mozilla::gfx::UnknownUnits, float>
const&, mozilla::gfx::PointTyped<mozilla::gfx::UnknownUnits, float>*) const
/home/max/src/firefox/gfx/2d/Matrix.h:738:19
#2 0x7fe25e3a2329 in mozilla::gfx::RectTyped<mozilla::gfx::UnknownUnits,
float> mozilla::gfx::Matrix4x4Typed<mozilla::gfx::UnknownUnits,
mozilla::gfx::UnknownUnits>::TransformAndClipBounds<float>(mozilla::gfx::RectTyped<mozilla::gfx::UnknownUnits,
float> const&, mozilla::gfx::RectTyped<mozilla::gfx::UnknownUnits, float>
const&) const /home/max/src/firefox/gfx/2d/Matrix.h:675:24
#3 0x7fe25ea08163 in
mozilla::layers::BasicCompositor::DrawQuad(mozilla::gfx::RectTyped<mozilla::gfx::UnknownUnits,
float> const&, mozilla::gfx::RectTyped<mozilla::gfx::UnknownUnits, float>
const&, mozilla::layers::EffectChain const&, float,
mozilla::gfx::Matrix4x4Typed<mozilla::gfx::UnknownUnits,
mozilla::gfx::UnknownUnits> const&,
mozilla::gfx::RectTyped<mozilla::gfx::UnknownUnits, float> const&)
/home/max/src/firefox/gfx/layers/basic/BasicCompositor.cpp:311:23
#4 0x7fe25e888778 in
mozilla::layers::Compositor::DrawQuad(mozilla::gfx::RectTyped<mozilla::gfx::UnknownUnits,
float> const&, mozilla::gfx::RectTyped<mozilla::gfx::UnknownUnits, float>
const&, mozilla::layers::EffectChain const&, float,
mozilla::gfx::Matrix4x4Typed<mozilla::gfx::UnknownUnits,
mozilla::gfx::UnknownUnits> const&)
/home/max/src/firefox/objdir-ff-asan-O0/dist/include/mozilla/layers/Compositor.h:331:7
#5 0x7fe25eb0b14f in
mozilla::layers::ColorLayerComposite::RenderLayer(mozilla::gfx::IntRectTyped<mozilla::gfx::UnknownUnits>
const&)::$_1::operator()(mozilla::layers::EffectChain&,
mozilla::gfx::RectTyped<mozilla::gfx::UnknownUnits, float> const&) const
/home/max/src/firefox/gfx/layers/composite/ColorLayerComposite.cpp:31:5
#6 0x7fe25ead8bdd in void
mozilla::layers::RenderWithAllMasks<mozilla::layers::ColorLayerComposite::RenderLayer(mozilla::gfx::IntRectTyped<mozilla::gfx::UnknownUnits>
const&)::$_1>(mozilla::layers::Layer*, mozilla::layers::Compositor*,
mozilla::gfx::IntRectTyped<mozilla::gfx::UnknownUnits> const&,
mozilla::layers::ColorLayerComposite::RenderLayer(mozilla::gfx::IntRectTyped<mozilla::gfx::UnknownUnits>
const&)::$_1)
/home/max/src/firefox/gfx/layers/composite/LayerManagerComposite.h:616:5
#7 0x7fe25ead8437 in
mozilla::layers::ColorLayerComposite::RenderLayer(mozilla::gfx::IntRectTyped<mozilla::gfx::UnknownUnits>
const&) /home/max/src/firefox/gfx/layers/composite/ColorLayerComposite.cpp:28:3
#8 0x7fe25eb749e6 in void
mozilla::layers::RenderLayers<mozilla::layers::ContainerLayerComposite>(mozilla::layers::ContainerLayerComposite*,
mozilla::layers::LayerManagerComposite*,
mozilla::gfx::IntRectTyped<mozilla::RenderTargetPixel> const&)
/home/max/src/firefox/gfx/layers/composite/ContainerLayerComposite.cpp:662:7
...................
Address 0x7fe22dbc417c is located in stack of thread T39 (Compositor) at offset
28 in frame
#0 0x7fe25e3b6b8f in unsigned long
mozilla::gfx::Matrix4x4Typed<mozilla::gfx::UnknownUnits,
mozilla::gfx::UnknownUnits>::TransformAndClipRect<float>(mozilla::gfx::RectTyped<mozilla::gfx::UnknownUnits,
float> const&, mozilla::gfx::RectTyped<mozilla::gfx::UnknownUnits, float>
const&, mozilla::gfx::PointTyped<mozilla::gfx::UnknownUnits, float>*) const
/home/max/src/firefox/gfx/2d/Matrix.h:709
This frame has 20 object(s):
[32, 1056) 'points' <== Memory access at offset 28 underflows this variable
[1184, 1200) 'ref.tmp'
[1216, 1232) 'ref.tmp2'
[1248, 1264) 'ref.tmp4'
[1280, 1296) 'ref.tmp5'
[1312, 1328) 'ref.tmp11'
[1344, 1360) 'ref.tmp12'
[1376, 1392) 'ref.tmp18'
[1408, 1424) 'ref.tmp19'
[1440, 1504) 'planeNormals'
[1536, 1552) 'ref.tmp32'
[1568, 1584) 'ref.tmp35'
[1600, 1616) 'ref.tmp38'
[1632, 1648) 'ref.tmp42'
[1664, 1680) 'ref.tmp68'
[1696, 1712) 'coerce'
[1728, 1744) 'ref.tmp71'
[1760, 1768) 'p'
[1792, 1800) 'ref.tmp99'
[1824, 1832) 'ref.tmp100'
HINT: this may be a false positive if your program uses some custom stack
unwind mechanism or swapcontext
(longjmp and C++ exceptions *are* supported)
SUMMARY: AddressSanitizer: stack-buffer-underflow
/home/max/src/firefox/gfx/2d/BasePoint4D.h:101:68 in
mozilla::gfx::BasePoint4D<float,
mozilla::gfx::Point4DTyped<mozilla::gfx::UnknownUnits, float>
>::DotProduct(mozilla::gfx::Point4DTyped<mozilla::gfx::UnknownUnits, float>
const&) const
Shadow bytes around the buggy address:
0x0ffcc5b707d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0ffcc5b707e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0ffcc5b707f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0ffcc5b70800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0ffcc5b70810: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0ffcc5b70820: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1[f1]
0x0ffcc5b70830: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0ffcc5b70840: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0ffcc5b70850: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0ffcc5b70860: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0ffcc5b70870: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable: 00
Partially addressable: 01 02 03 04 05 06 07
Heap left redzone: fa
Heap right redzone: fb
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack partial redzone: f4
Stack after return: f5
Stack use after scope: f8
Global redzone: f9
Global init order: f6
Poisoned by user: f7
Container overflow: fc
Array cookie: ac
Intra object redzone: bb
ASan internal: fe
Left alloca redzone: ca
Right alloca redzone: cb
So, I'm pretty sure this is a bug in Firefox code, not in GCC. I don't know why
clang didn't detect this on -O2 level (optimized out?), perhaps you'll want
file an issue in LLVM bugzilla. Anyway, I believe GCC is fine here.
