While making crashpad_minidump_test run in Chromium’s try- and buildbots
(https://crbug.com/779790), crashes in the
MinidumpThreadWriter.OneThread_AMD64_Stack test were observed in 32-bit
x86 Windows builds produced by Clang in the release configuration. These
crashes occurred in crashpad::test::InitializeMinidumpContextAMD64,
which heap-allocates a MinidumpContextAMD64Writer object. These objects
have an alignment requirement of 16, based on the alignment requirement
of their MinidumpContextAMD64 member.
Although this problem was never observed with MSVC, Clang was making use
of the known strict alignment and producing code that depended on it.
This code crashed if the requirement was not met. MSVC had raised a
warning about this usage (C4316), but the warning was disabled as it did
not appear to have any ill effect on code produced by that compiler.
The problem surfaced in test code, but heap-allocated
MinidumpContextAMD64Writer objects are created in non-test code as well.
The impact is limited, because a 32-bit Windows Crashpad handler would
not have a need to allocate one of these objects.
As a fix, MinidumpContextAMD64Writer is given a custom allocation
function (a static “operator new()” member and matching “operator
delete()”) that returns properly aligned memory.
Change-Id: I0cb924da91716eb01b88ec2ae952a69262cc2de6
Reviewed-on: https://chromium-review.googlesource.com/746539
Reviewed-by: Leonard Mosescu <mosescu@chromium.org>
This was missed in Crashpad 8c35d92ae403. It syncs with Chromium
16289b3ef759.
Change-Id: I7e92e71fc940e25e751e7487d100b5684bdbf667
Reviewed-on: https://chromium-review.googlesource.com/535577
Commit-Queue: Mark Mentovai <mark@chromium.org>
Reviewed-by: Scott Graham <scottmg@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
Use the standard alignas instead of ALIGNAS in cases where this is
possible too. It’s not currently possible where ALIGNAS may be mixed
with other attributes, although the not-landed
https://codereview.chromium.org/2670873002/ suggests that where ALIGNAS
is mixed with __attribute__((packed)), it’s viable to write “struct
alignas(4) S { /* … */ } __attribute__((packed));”.
This includes an update of mini_chromium to
723e840a2f100a525f7feaad2e93df31d701780a, picking up:
723e840a2f10 Remove ALIGNOF
This tracks upstream https://codereview.chromium.org/2932053002/.
Change-Id: I7ddaf829020ef3be0512f803cecbb7c543294f07
Reviewed-on: https://chromium-review.googlesource.com/533356
Reviewed-by: Scott Graham <scottmg@chromium.org>
Commit-Queue: Mark Mentovai <mark@chromium.org>
MEMORY_BASIC_INFORMATION64 specifies an alignment of 16, but the
standard allocator used by containers doesn't honor this. Although 16
is the default alignment size used on Windows for x86_64, it's not for
32-bit x86. clang assumed that the alignment of the structure was as
declared, and used an SSE load sequence that required this alignment.
AlignedAllocator is a replacement for std::allocator that allows the
alignment to be specified. AlignedVector is an std::vector<> that uses
AlignedAllocator instead of std::allocator.
BUG=chromium:564691
R=scottmg@chromium.org
Review URL: https://codereview.chromium.org/1498133002 .
