Re: [PATCH] PM: hibernate: use __get_safe_page() rather than touching the list.

On Thu, Sep 21, 2023 at 7:01 PM Brian Geffon bgeffon@google.com 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@google.com Fixes: 8357376 ("swsusp: Improve handling of highmem") Cc: stable@vger.kernel.org

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!