linux-kernel - Re: [tip: x86/mm] x86/mm/pat: Fix VM_PAT handling when fork() fails in copy_page

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: <fe0a67dc-d7cb-42ff-9b20-9527af7f6a94@redhat.com>
Date: Wed, 19 Mar 2025 09:15:25 +0100
From: David Hildenbrand <david@...hat.com>
To: linux-kernel@...r.kernel.org, linux-tip-commits@...r.kernel.org
Cc: xingwei lee <xrivendell7@...il.com>, yuxin wang <wang1315768607@....com>,
 Marius Fleischer <fleischermarius@...il.com>, Ingo Molnar
 <mingo@...nel.org>, Andrew Morton <akpm@...ux-foundation.org>,
 Linus Torvalds <torvalds@...ux-foundation.org>,
 Dave Hansen <dave.hansen@...ux.intel.com>, Andy Lutomirski
 <luto@...nel.org>, Peter Zijlstra <peterz@...radead.org>,
 Rik van Riel <riel@...riel.com>, "H. Peter Anvin" <hpa@...or.com>,
 Peter Xu <peterx@...hat.com>, x86@...nel.org,
 Dan Carpenter <dan.carpenter@...aro.org>
Subject: Re: [tip: x86/mm] x86/mm/pat: Fix VM_PAT handling when fork() fails
 in copy_page_range()

> +void untrack_pfn_copy(struct vm_area_struct *dst_vma,
> +		struct vm_area_struct *src_vma)
> +{
> +	resource_size_t paddr;
> +	unsigned long size;
> +
> +	if (!(dst_vma->vm_flags & VM_PAT))
> +		return;
> +
> +	/*
> +	 * As the page tables might not have been copied yet, the PAT
> +	 * information is obtained from the src VMA, just like during
> +	 * track_pfn_copy().
> +	 */
> +	if (get_pat_info(src_vma, &paddr, NULL)) {
> +		size = src_vma->vm_end - src_vma->vm_start;
> +		free_pfn_range(paddr, size);
>   	}
>   

@Ingo, can you drop this patch for now? It's supposed to be 
"!get_pat_info" here, and I want to re-verify now that a couple of 
months passed, whether it's all working as expected with that.

(we could actually complain if get_pat_info() would fail at this point, 
let me think about that)

I'll resend once I get to it. Thanks!

-- 
Cheers,

David / dhildenb