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Code Issues Releases Wiki Activity

ircd::ctx: Further fix and clarify the POST/DETACH leak potential.

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This commit is contained in:
Jason Volk 2017-11-06 12:10:55 -08:00
parent 8811bf8a51
commit 99e431c8da
2 changed files with 20 additions and 8 deletions
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1
include/ircd/ctx/context.h
View file

@ -60,6 +60,7 @@ namespace ircd::ctx
struct ircd::ctx::context
{
enum flags
:uint
{
POST = 0x01, ///< Defers spawn with an ios.post()
DISPATCH = 0x02, ///< Defers spawn with an ios.dispatch() (possibly)

27
ircd/ctx.cc
View file

@ -540,20 +540,29 @@ ircd::ctx::context::context(const char *const &name,
function func)
:c{std::make_unique<ctx>(name, stack_sz, flags, ircd::ios)}
{
// The profiler is told about the spawn request here, not inside the closure
// which is probably the same event-slice as event::CUR_ENTER and not as useful.
mark(prof::event::SPAWN);
auto spawn
{
std::bind(&ircd::ctx::spawn, c.get(), std::move(func))
};
const unwind release{[this, &flags]
// The profiler is told about the spawn request here, not inside the closure
// which is probably the same event-slice as event::CUR_ENTER and not as useful.
mark(prof::event::SPAWN);
// When the user passes the DETACH flag we want to release the unique_ptr
// of the ctx if and only if that ctx is committed to freeing itself. Our
// commitment ends at the 180 of this function. If no exception was thrown
// we expect the context to be committed to entry. If the POST flag is
// supplied and it gets lost in the asio queue it will not be entered, and
// will not be able to free itself; that will leak.
const unwind::nominal release
{
if(flags & DETACH)
this->c.release();
}};
[this, &flags]
{
if(flags & context::DETACH)
this->detach();
}
};
if(flags & POST)
{
@ -644,6 +653,7 @@ ircd::ctx::context::join()
return;
mark(prof::event::JOIN);
assert(bool(c));
assert(!c->adjoindre);
c->adjoindre = &cur(); // Set the target context to notify this context when it finishes
wait();
@ -653,6 +663,7 @@ ircd::ctx::context::join()
ircd::ctx::ctx *
ircd::ctx::context::detach()
{
assert(bool(c));
c->flags |= DETACH;
return c.release();
}