On Thu, Sep 21, 2023 at 7:01 PM Brian Geffon <bgeffon@xxxxxxxxxx> wrote:
>
> We found at least one situation where the safe pages list was empty and
> get_buffer() would gladly try to use a NULL pointer.
>
> Signed-off-by: Brian Geffon <bgeffon@xxxxxxxxxx>
> Fixes: 8357376 ("swsusp: Improve handling of highmem")
> Cc: stable@xxxxxxxxxxxxxxx
>
> Change-Id: Ibb43a9b4ac5ff2d7e3021fdacc08e116650231e9
> ---
> kernel/power/snapshot.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
> index 362e6bae5891..2dcb33248518 100644
> --- a/kernel/power/snapshot.c
> +++ b/kernel/power/snapshot.c
> @@ -2544,8 +2544,9 @@ static void *get_highmem_page_buffer(struct page *page,
> pbe->copy_page = pfn_to_page(pfn);
> } else {
> /* Copy of the page will be stored in normal memory */
> - kaddr = safe_pages_list;
> - safe_pages_list = safe_pages_list->next;
> + kaddr = __get_safe_page(ca->gfp_mask);
> + if (!kaddr)
> + return ERR_PTR(-ENOMEM);
> pbe->copy_page = virt_to_page(kaddr);
> }
> pbe->next = highmem_pblist;
> @@ -2747,8 +2748,9 @@ static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca)
> return ERR_PTR(-ENOMEM);
> }
> pbe->orig_address = page_address(page);
> - pbe->address = safe_pages_list;
> - safe_pages_list = safe_pages_list->next;
> + pbe->address = __get_safe_page(ca->gfp_mask);
> + if (!pbe->address)
> + return ERR_PTR(-ENOMEM);
> pbe->next = restore_pblist;
> restore_pblist = pbe;
> return pbe->address;
> --
Applied as 6.7 material, thanks!
