Hi!
On 2023-02-14T15:11:14+0000, Andrew Stubbs <a...@codesourcery.com> wrote:
> On 14/02/2023 12:54, Thomas Schwinge wrote:
>> On 2022-01-13T11:13:51+0000, Andrew Stubbs <a...@codesourcery.com> wrote:
>>> Updated patch: this version fixes some missed cases of malloc in the
>>> realloc implementation.
>>
>> Right, and as it seems I've run into another issue: a stray 'free'.
>>
>>> --- a/libgomp/allocator.c
>>> +++ b/libgomp/allocator.c
>>
>> Re 'omp_realloc':
>>
>>> @@ -660,9 +709,10 @@ retry:
>>> gomp_mutex_unlock (&allocator_data->lock);
>>> #endif
>>> if (prev_size)
>>> - new_ptr = realloc (data->ptr, new_size);
>>> + new_ptr = MEMSPACE_REALLOC (allocator_data->memspace, data->ptr,
>>> + data->size, new_size);
>>> else
>>> - new_ptr = malloc (new_size);
>>> + new_ptr = MEMSPACE_ALLOC (allocator_data->memspace, new_size);
>>> if (new_ptr == NULL)
>>> {
>>> #ifdef HAVE_SYNC_BUILTINS
>>> @@ -690,7 +740,11 @@ retry:
>>> && (free_allocator_data == NULL
>>> || free_allocator_data->pool_size == ~(uintptr_t) 0))
>>> {
>>> - new_ptr = realloc (data->ptr, new_size);
>>> + omp_memspace_handle_t memspace __attribute__((unused))
>>> + = (allocator_data
>>> + ? allocator_data->memspace
>>> + : predefined_alloc_mapping[allocator]);
>>> + new_ptr = MEMSPACE_REALLOC (memspace, data->ptr, data->size,
>>> new_size);
>>> if (new_ptr == NULL)
>>> goto fail;
>>> ret = (char *) new_ptr + sizeof (struct omp_mem_header);
>>> @@ -701,7 +755,11 @@ retry:
>>> }
>>> else
>>> {
>>> - new_ptr = malloc (new_size);
>>> + omp_memspace_handle_t memspace __attribute__((unused))
>>> + = (allocator_data
>>> + ? allocator_data->memspace
>>> + : predefined_alloc_mapping[allocator]);
>>> + new_ptr = MEMSPACE_ALLOC (memspace, new_size);
>>> if (new_ptr == NULL)
>>> goto fail;
>>> }
>>> @@ -735,32 +793,35 @@ retry:
>> | free (data->ptr);
>>> return ret;
>>
>> I run into a SIGSEGV if a non-'malloc'-based allocation is 'free'd here.
>>
>> The attached
>> "In 'libgomp/allocator.c:omp_realloc', route 'free' through 'MEMSPACE_FREE'"
>> appears to resolve my issue, but not yet regression-tested.
No issues in testing.
>> Does that
>> look correct to you?
>
> That looks correct.
Thanks. I've pushed to devel/omp/gcc-12 branch
commit 3a2c07395b0a565955a7b86f0eba866937e15989
"In 'libgomp/allocator.c:omp_realloc', route 'free' through 'MEMSPACE_FREE'",
see attached.
> The only remaining use of "free" should be the one
> referring to the allocator object itself (i.e. the destructor).
ACK.
>> Or, instead of invoking 'MEMSPACE_FREE', should we scrap the
>> 'used_pool_size' bookkeeping here, and just invoke 'omp_free' instead?
>>
>> --- libgomp/allocator.c
>> +++ libgomp/allocator.c
>> @@ -842,19 +842,7 @@ retry:
>> if (old_size - old_alignment < size)
>> size = old_size - old_alignment;
>> memcpy (ret, ptr, size);
>> - if (__builtin_expect (free_allocator_data
>> - && free_allocator_data->pool_size < ~(uintptr_t) 0,
>> 0))
>> - {
>> -#ifdef HAVE_SYNC_BUILTINS
>> - __atomic_add_fetch (&free_allocator_data->used_pool_size,
>> -data->size,
>> - MEMMODEL_RELAXED);
>> -#else
>> - gomp_mutex_lock (&free_allocator_data->lock);
>> - free_allocator_data->used_pool_size -= data->size;
>> - gomp_mutex_unlock (&free_allocator_data->lock);
>> -#endif
>> - }
>> - free (data->ptr);
>> + ialias_call (omp_free) (ptr, free_allocator);
>> return ret;
>>
>> (I've not yet analyzed whether that's completely equivalent.)
>
> The used_pool_size code comes from upstream, so if you want to go beyond
> the mechanical substitution of "free" then you're adding a new patch
> (rather than tweaking an old one). I'll leave that for others to comment on.
And I'll leave that for another day, and/or another person. ;-)
Grüße
Thomas
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>From 3a2c07395b0a565955a7b86f0eba866937e15989 Mon Sep 17 00:00:00 2001
From: Thomas Schwinge <tho...@codesourcery.com>
Date: Tue, 14 Feb 2023 13:35:03 +0100
Subject: [PATCH] In 'libgomp/allocator.c:omp_realloc', route 'free' through
'MEMSPACE_FREE'
... to not run into a SIGSEGV if a non-'malloc'-based allocation is 'free'd
here.
Fix-up for og12 commit c5d1d7651297a273321154a5fe1b01eba9dcf604
"libgomp, nvptx: low-latency memory allocator".
libgomp/
* allocator.c (omp_realloc): Route 'free' through 'MEMSPACE_FREE'.
---
libgomp/ChangeLog.omp | 2 ++
libgomp/allocator.c | 12 +++++++++++-
2 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/libgomp/ChangeLog.omp b/libgomp/ChangeLog.omp
index 530f5c6acf6..819a5333907 100644
--- a/libgomp/ChangeLog.omp
+++ b/libgomp/ChangeLog.omp
@@ -1,5 +1,7 @@
2023-02-16 Thomas Schwinge <tho...@codesourcery.com>
+ * allocator.c (omp_realloc): Route 'free' through 'MEMSPACE_FREE'.
+
* config/linux/allocator.c (linux_memspace_alloc)
(linux_memspace_calloc): Clarify zero-initialization for pinned
memory.
diff --git a/libgomp/allocator.c b/libgomp/allocator.c
index 05b323d458e..ba9a4e17cc2 100644
--- a/libgomp/allocator.c
+++ b/libgomp/allocator.c
@@ -854,7 +854,17 @@ retry:
gomp_mutex_unlock (&free_allocator_data->lock);
#endif
}
- free (data->ptr);
+ {
+ omp_memspace_handle_t was_memspace __attribute__((unused))
+ = (free_allocator_data
+ ? free_allocator_data->memspace
+ : predefined_alloc_mapping[free_allocator]);
+ int was_pinned __attribute__((unused))
+ = (free_allocator_data
+ ? free_allocator_data->pinned
+ : free_allocator == ompx_pinned_mem_alloc);
+ MEMSPACE_FREE (was_memspace, data->ptr, data->size, was_pinned);
+ }
return ret;
fail:
--
2.25.1
