From: John Hubbard <jhubbard@nvidia.com>
To: Andrew Morton <akpm@linux-foundation.org>,
Miaohe Lin <linmiaohe@huawei.com>, <imbrenda@linux.ibm.com>,
<kirill.shutemov@linux.intel.com>, <jack@suse.cz>,
<linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 4/5] mm: gup: fix potential pgmap refcnt leak in __gup_device_huge()
Date: Sun, 8 Aug 2021 14:16:53 -0700 [thread overview]
Message-ID: <87f2ff42-9d96-3ecb-dada-d347a3fa95e6@nvidia.com> (raw)
In-Reply-To: <20210807114545.eaee318909a9215c4e056aa3@linux-foundation.org>
On 8/7/21 11:45 AM, Andrew Morton wrote:
> On Sat, 7 Aug 2021 11:41:12 -0700 Andrew Morton <akpm@linux-foundation.org> wrote:
>
>> We can simplify further, and remove the troublesome multiple return points?
>>
>
> oops.
I sent a reviewed by to the "+" fixup email, but just realized that that did not
hit the main
mailing list. So:
For the end result of these stacked fixes to this file:
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
thanks,
--
John Hubbard
NVIDIA
>
> --- a/mm/gup.c~mm-gup-fix-potential-pgmap-refcnt-leak-in-__gup_device_huge-fix-fix
> +++ a/mm/gup.c
> @@ -2240,6 +2240,7 @@ static int __gup_device_huge(unsigned lo
> {
> int nr_start = *nr;
> struct dev_pagemap *pgmap = NULL;
> + int ret = 1;
>
> do {
> struct page *page = pfn_to_page(pfn);
> @@ -2247,12 +2248,14 @@ static int __gup_device_huge(unsigned lo
> pgmap = get_dev_pagemap(pfn, pgmap);
> if (unlikely(!pgmap)) {
> undo_dev_pagemap(nr, nr_start, flags, pages);
> + ret = 0;
> break;
> }
> SetPageReferenced(page);
> pages[*nr] = page;
> if (unlikely(!try_grab_page(page, flags))) {
> undo_dev_pagemap(nr, nr_start, flags, pages);
> + ret = 0;
> break;
> }
> (*nr)++;
> @@ -2260,7 +2263,7 @@ static int __gup_device_huge(unsigned lo
> } while (addr += PAGE_SIZE, addr != end);
>
> put_dev_pagemap(pgmap);
> - return 1;
> + return ret;
> }
>
> static int __gup_device_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr,
>
> Not sure if it's worth bothering, really...
>
next prev parent reply other threads:[~2021-08-08 21:17 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-07 9:36 [PATCH 0/5] Cleanups and fixup for gup Miaohe Lin
2021-08-07 9:36 ` [PATCH 1/5] mm: gup: remove set but unused local variable major Miaohe Lin
2021-08-09 9:21 ` David Hildenbrand
2021-08-07 9:36 ` [PATCH 2/5] mm: gup: remove unneed local variable orig_refs Miaohe Lin
2021-08-09 9:22 ` David Hildenbrand
2021-08-07 9:36 ` [PATCH 3/5] mm: gup: remove useless BUG_ON in __get_user_pages() Miaohe Lin
2021-08-09 9:23 ` David Hildenbrand
2021-08-07 9:36 ` [PATCH 4/5] mm: gup: fix potential pgmap refcnt leak in __gup_device_huge() Miaohe Lin
2021-08-07 18:41 ` Andrew Morton
2021-08-07 18:45 ` Andrew Morton
2021-08-08 21:16 ` John Hubbard [this message]
2021-08-07 9:36 ` [PATCH 5/5] mm: gup: use helper PAGE_ALIGNED in populate_vma_page_range() Miaohe Lin
2021-08-09 9:24 ` David Hildenbrand
2021-08-08 21:13 ` [PATCH 0/5] Cleanups and fixup for gup John Hubbard
2021-08-09 9:39 ` Claudio Imbrenda
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