linux-kernel - Re: [PATCH v2 07/10] mm/kasan: Support non-blocking GFP in kasan_populate

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <aMt2RBzoKB9iodtR@MiWiFi-R3L-srv>
Date: Thu, 18 Sep 2025 11:02:28 +0800
From: Baoquan He <bhe@...hat.com>
To: "Uladzislau Rezki (Sony)" <urezki@...il.com>
Cc: linux-mm@...ck.org, Andrew Morton <akpm@...ux-foundation.org>,
	Michal Hocko <mhocko@...nel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Andrey Ryabinin <ryabinin.a.a@...il.com>,
	Alexander Potapenko <glider@...gle.com>
Subject: Re: [PATCH v2 07/10] mm/kasan: Support non-blocking GFP in
 kasan_populate_vmalloc()

On 09/15/25 at 03:40pm, Uladzislau Rezki (Sony) wrote:
> A "gfp_mask" is already passed to kasan_populate_vmalloc() as
> an argument to respect GFPs from callers and KASAN uses it for
> its internal allocations.
> 
> But apply_to_page_range() function ignores GFP flags due to a
> hard-coded mask.
> 
> Wrap the call with memalloc_apply_gfp_scope()/memalloc_restore_scope()
> so that non-blocking GFP flags(GFP_ATOMIC, GFP_NOWAIT) are respected.
> 
> Cc: Andrey Ryabinin <ryabinin.a.a@...il.com>
> Cc: Alexander Potapenko <glider@...gle.com>
> Signed-off-by: Uladzislau Rezki (Sony) <urezki@...il.com>
> ---
>  mm/kasan/shadow.c | 12 ++----------
>  1 file changed, 2 insertions(+), 10 deletions(-)

Reviewed-by: Baoquan He <bhe@...hat.com>

> 
> diff --git a/mm/kasan/shadow.c b/mm/kasan/shadow.c
> index 11d472a5c4e8..c6643a72d9f6 100644
> --- a/mm/kasan/shadow.c
> +++ b/mm/kasan/shadow.c
> @@ -377,18 +377,10 @@ static int __kasan_populate_vmalloc(unsigned long start, unsigned long end, gfp_
>  		 * page tables allocations ignore external gfp mask, enforce it
>  		 * by the scope API
>  		 */
> -		if ((gfp_mask & (__GFP_FS | __GFP_IO)) == __GFP_IO)
> -			flags = memalloc_nofs_save();
> -		else if ((gfp_mask & (__GFP_FS | __GFP_IO)) == 0)
> -			flags = memalloc_noio_save();
> -
> +		flags = memalloc_apply_gfp_scope(gfp_mask);
>  		ret = apply_to_page_range(&init_mm, start, nr_pages * PAGE_SIZE,
>  					  kasan_populate_vmalloc_pte, &data);
> -
> -		if ((gfp_mask & (__GFP_FS | __GFP_IO)) == __GFP_IO)
> -			memalloc_nofs_restore(flags);
> -		else if ((gfp_mask & (__GFP_FS | __GFP_IO)) == 0)
> -			memalloc_noio_restore(flags);
> +		memalloc_restore_scope(flags);
>  
>  		___free_pages_bulk(data.pages, nr_pages);
>  		if (ret)
> -- 
> 2.47.3
>