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Fix memory corruption caused by GC-invisible coroutine stacks

Browse source 
Crucially this introduces BoehmGCStackAllocator, but it also
adds a bunch of wiring to avoid making libutil depend on bdw-gc.

Part of the solutions for #4178, #4200
This commit is contained in:
Robert Hensing 2020-10-30 20:55:53 +01:00
parent dc5696b84f
commit c4d903ddb0
4 changed files with 75 additions and 2 deletions
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35
src/libutil/serialise.cc
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@ -171,6 +171,39 @@ size_t StringSource::read(unsigned char * data, size_t len)
#error Coroutines are broken in this version of Boost!
#endif
/* A concrete datatype allow virtual dispatch of stack allocation methods. */
struct VirtualStackAllocator {
StackAllocator *allocator = StackAllocator::defaultAllocator;
boost::context::stack_context allocate() {
return allocator->allocate();
}
void deallocate(boost::context::stack_context sctx) {
allocator->deallocate(sctx);
}
};
/* This class reifies the default boost coroutine stack allocation strategy with
a virtual interface. */
class DefaultStackAllocator : public StackAllocator {
boost::coroutines2::default_stack stack;
boost::context::stack_context allocate() {
return stack.allocate();
}
void deallocate(boost::context::stack_context sctx) {
deallocate(sctx);
}
};
static DefaultStackAllocator defaultAllocatorSingleton;
StackAllocator *StackAllocator::defaultAllocator = &defaultAllocatorSingleton;
std::unique_ptr<Source> sinkToSource(
std::function<void(Sink &)> fun,
std::function<void()> eof)
@ -195,7 +228,7 @@ std::unique_ptr<Source> sinkToSource(
size_t read(unsigned char * data, size_t len) override
{
if (!coro)
coro = coro_t::pull_type([&](coro_t::push_type & yield) {
coro = coro_t::pull_type(VirtualStackAllocator{}, [&](coro_t::push_type & yield) {
LambdaSink sink([&](const unsigned char * data, size_t len) {
if (len) yield(std::string((const char *) data, len));
});