Re: Patch "mm: call arch_swap_restore() from do_swap_page()" has been added to the 5.10-stable tree

[Greg KH <gregkh@linuxfoundation.org>]

On Sun, Jul 09, 2023 at 11:44:01AM +0200, gregkh@linuxfoundation.org wrote:
> 
> This is a note to let you know that I've just added the patch titled
> 
>     mm: call arch_swap_restore() from do_swap_page()
> 
> to the 5.10-stable tree which can be found at:
>     http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
> 
> The filename of the patch is:
>      mm-call-arch_swap_restore-from-do_swap_page.patch
> and it can be found in the queue-5.10 subdirectory.
> 
> If you, or anyone else, feels it should not be added to the stable tree,
> please let <stable@vger.kernel.org> know about it.
> 
> 
> >From 6dca4ac6fc91fd41ea4d6c4511838d37f4e0eab2 Mon Sep 17 00:00:00 2001
> From: Peter Collingbourne <pcc@google.com>
> Date: Mon, 22 May 2023 17:43:08 -0700
> Subject: mm: call arch_swap_restore() from do_swap_page()
> 
> From: Peter Collingbourne <pcc@google.com>
> 
> commit 6dca4ac6fc91fd41ea4d6c4511838d37f4e0eab2 upstream.
> 
> Commit c145e0b47c77 ("mm: streamline COW logic in do_swap_page()") moved
> the call to swap_free() before the call to set_pte_at(), which meant that
> the MTE tags could end up being freed before set_pte_at() had a chance to
> restore them.  Fix it by adding a call to the arch_swap_restore() hook
> before the call to swap_free().
> 
> Link: https://lkml.kernel.org/r/20230523004312.1807357-2-pcc@google.com
> Link: https://linux-review.googlesource.com/id/I6470efa669e8bd2f841049b8c61020c510678965
> Fixes: c145e0b47c77 ("mm: streamline COW logic in do_swap_page()")
> Signed-off-by: Peter Collingbourne <pcc@google.com>
> Reported-by: Qun-wei Lin <Qun-wei.Lin@mediatek.com>
> Closes: https://lore.kernel.org/all/5050805753ac469e8d727c797c2218a9d780d434.camel@mediatek.com/
> Acked-by: David Hildenbrand <david@redhat.com>
> Acked-by: "Huang, Ying" <ying.huang@intel.com>
> Reviewed-by: Steven Price <steven.price@arm.com>
> Acked-by: Catalin Marinas <catalin.marinas@arm.com>
> Cc: <stable@vger.kernel.org>	[6.1+]
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
>  mm/memory.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/mm/memory.c b/mm/memory.c
> index 0ae594703021..01f39e8144ef 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -3950,6 +3950,13 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
>  		}
>  	}
>  
> +	/*
> +	 * Some architectures may have to restore extra metadata to the page
> +	 * when reading from swap. This metadata may be indexed by swap entry
> +	 * so this must be called before swap_free().
> +	 */
> +	arch_swap_restore(entry, folio);
> +
>  	/*
>  	 * Remove the swap entry and conditionally try to free up the swapcache.
>  	 * We're already holding a reference on the page but haven't mapped it
> -- 
> 2.41.0
> 
> 
> 
> Patches currently in stable-queue which might be from pcc@google.com are
> 
> queue-5.10/mm-call-arch_swap_restore-from-do_swap_page.patch

Oops, my fault, does not belong in 5.10, now dropped.