Hi Chung-Lin!
On Fri, 14 Dec 2018 22:28:58 +0800, Chung-Lin Tang <chunglin_t...@mentor.com>
wrote:
> On 2018/12/13 11:51 PM, Thomas Schwinge wrote:
> > On Thu, 13 Dec 2018 23:28:49 +0800, Chung-Lin
> > Tang<chunglin_t...@mentor.com> wrote:
> >> On 2018/12/7 6:26 AM, Julian Brown wrote:
> >>> On Thu, 6 Dec 2018 22:22:46 +0000
> >>> Julian Brown<jul...@codesourcery.com> wrote:
> >>>
> >>>> On Thu, 6 Dec 2018 21:42:14 +0100
> >>>> Thomas Schwinge<tho...@codesourcery.com> wrote:
> >>>>
> >>>>> [...]
> >>>>> ..., where the "Invalid read of size 8" happens, and which
> >>>>> eventually would try to "free (tgt)" again, via
> >>>>> libgomp/target.c:gomp_unmap_tgt:
> >>>>>
> >>>>> attribute_hidden void
> >>>>> gomp_unmap_tgt (struct target_mem_desc *tgt)
> >>>>> {
> >>>>> /* Deallocate on target the tgt->tgt_start .. tgt->tgt_end
> >>>>> region. */ if (tgt->tgt_end)
> >>>>> gomp_free_device_memory (tgt->device_descr, tgt->to_free);
> >>>>>
> >>>>> free (tgt->array);
> >>>>> free (tgt);
> >>>>> }
> >>>>>
> >>>>> Is the "free (tgt)" in libgomp/target.c:gomp_unmap_vars_async wrong,
> >>>>> or something else?
>
> I think I understand the problem now. In gomp_unmap_vars_async(), in the case
> of
> tgt->list_count == 0 (i.e. no map arguments at all) the code should simply
> free the tgt
> and return, while the code in goacc_async_copyout_unmap_vars() didn't handle
> this case
> and always scheduled an asynchronous free of the tgt later, causing that
> valgrind error
> you see.
>
> I am still testing the attached patch, but I think it is the right fix: I
> reviewed what I
> wrote and it seemed the way I organized things into a
> goacc_async_copyout_unmap_vars() routine,
> including the hackish refcount++, etc. is simply unneeded. I have deleted
> those stuff
> and consolidated things back into gomp_unmap_vars_async().
>
> I'll update the whole patches later after complete testing, the attached is
> the patch atop
> of the prior async patches. (the small program you gave above does pass
> valgrind now)
Thanks, confirmed.
Grüße
Thomas
> diff -ru trunk-orig/libgomp/oacc-async.c trunk-work/libgomp/oacc-async.c
> --- trunk-orig/libgomp/oacc-async.c 2018-12-14 21:06:06.649794724 +0800
> +++ trunk-work/libgomp/oacc-async.c 2018-12-14 22:11:29.252251925 +0800
> @@ -238,31 +238,6 @@
> thr->default_async = async;
> }
>
> -static void
> -goacc_async_unmap_tgt (void *ptr)
> -{
> - struct target_mem_desc *tgt = (struct target_mem_desc *) ptr;
> -
> - if (tgt->refcount > 1)
> - tgt->refcount--;
> - else
> - gomp_unmap_tgt (tgt);
> -}
> -
> -attribute_hidden void
> -goacc_async_copyout_unmap_vars (struct target_mem_desc *tgt,
> - struct goacc_asyncqueue *aq)
> -{
> - struct gomp_device_descr *devicep = tgt->device_descr;
> -
> - /* Increment reference to delay freeing of device memory until callback
> - has triggered. */
> - tgt->refcount++;
> - gomp_unmap_vars_async (tgt, true, aq);
> - devicep->openacc.async.queue_callback_func (aq, goacc_async_unmap_tgt,
> - (void *) tgt);
> -}
> -
> attribute_hidden void
> goacc_async_free (struct gomp_device_descr *devicep,
> struct goacc_asyncqueue *aq, void *ptr)
> diff -ru trunk-orig/libgomp/oacc-int.h trunk-work/libgomp/oacc-int.h
> --- trunk-orig/libgomp/oacc-int.h 2018-12-14 21:06:06.649794724 +0800
> +++ trunk-work/libgomp/oacc-int.h 2018-12-14 22:11:43.379947915 +0800
> @@ -104,8 +104,6 @@
>
> void goacc_init_asyncqueues (struct gomp_device_descr *);
> bool goacc_fini_asyncqueues (struct gomp_device_descr *);
> -void goacc_async_copyout_unmap_vars (struct target_mem_desc *,
> - struct goacc_asyncqueue *);
> void goacc_async_free (struct gomp_device_descr *, struct goacc_asyncqueue *,
> void *);
> struct goacc_asyncqueue *get_goacc_asyncqueue (int);
> diff -ru trunk-orig/libgomp/oacc-mem.c trunk-work/libgomp/oacc-mem.c
> --- trunk-orig/libgomp/oacc-mem.c 2018-12-14 21:06:06.649794724 +0800
> +++ trunk-work/libgomp/oacc-mem.c 2018-12-14 22:10:08.325998369 +0800
> @@ -911,7 +911,7 @@
> else
> {
> goacc_aq aq = get_goacc_asyncqueue (async);
> - goacc_async_copyout_unmap_vars (t, aq);
> + gomp_unmap_vars_async (t, true, aq);
> }
> }
>
> diff -ru trunk-orig/libgomp/oacc-parallel.c trunk-work/libgomp/oacc-parallel.c
> --- trunk-orig/libgomp/oacc-parallel.c 2018-12-14 21:06:06.649794724
> +0800
> +++ trunk-work/libgomp/oacc-parallel.c 2018-12-14 22:09:51.918353575
> +0800
> @@ -245,7 +245,7 @@
> {
> acc_dev->openacc.async.exec_func (tgt_fn, mapnum, hostaddrs, devaddrs,
> dims, tgt, aq);
> - goacc_async_copyout_unmap_vars (tgt, aq);
> + gomp_unmap_vars_async (tgt, true, aq);
> }
> }
>
> diff -ru trunk-orig/libgomp/target.c trunk-work/libgomp/target.c
> --- trunk-orig/libgomp/target.c 2018-12-14 21:06:06.653794622 +0800
> +++ trunk-work/libgomp/target.c 2018-12-14 20:42:03.629154346 +0800
> @@ -1072,6 +1072,17 @@
> return is_tgt_unmapped;
> }
>
> +static void
> +gomp_unref_tgt (void *ptr)
> +{
> + struct target_mem_desc *tgt = (struct target_mem_desc *) ptr;
> +
> + if (tgt->refcount > 1)
> + tgt->refcount--;
> + else
> + gomp_unmap_tgt (tgt);
> +}
> +
> /* Unmap variables described by TGT. If DO_COPYFROM is true, copy relevant
> variables back from device to host: if it is false, it is assumed that
> this
> has been done already. */
> @@ -1130,10 +1141,11 @@
> gomp_remove_var (devicep, k);
> }
>
> - if (tgt->refcount > 1)
> - tgt->refcount--;
> + if (aq)
> + devicep->openacc.async.queue_callback_func (aq, gomp_unref_tgt,
> + (void *) tgt);
> else
> - gomp_unmap_tgt (tgt);
> + gomp_unref_tgt ((void *) tgt);
>
> gomp_mutex_unlock (&devicep->lock);
> }
