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PM: hibernate: use __get_safe_page() rather than touching the list.

PATCH Applied Brian Geffon 3 participants 3 messages Sep 21, 2023 – Sep 22, 2023

Subsystems (3)
Stable branch Suspend to RAM Hibernation
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Brian Geffon

author
#0 lore raw

PATCH 1/1 PM: hibernate: use __get_safe_page() rather than touching the list.

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 <[email protected]>
Fixes 8357376 ("swsusp: Improve handling of highmem")
Cc [email protected]

Change-Id: Ibb43a9b4ac5ff2d7e3021fdacc08e116650231e9

---
 kernel/power/snapshot.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)
kernel/power/snapshot.c +6 -4
index 362e6bae5891..2dcb33248518 100644
@@ -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;
Signature · 1 line
2.42.0.459.ge4e396fd5e-goog
maintainer Applied
#1 lore raw
Quoted 32 lines · Brian Geffon

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 <[email protected]>
Fixes 8357376 ("swsusp: Improve handling of highmem")
Cc [email protected]

Change-Id: Ibb43a9b4ac5ff2d7e3021fdacc08e116650231e9

---
 kernel/power/snapshot.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)
kernel/power/snapshot.c +3 -2
index 362e6bae5891..2dcb33248518 100644
@@ -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);
        }

kernel/power/snapshot.c static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca)

Quoted 10 lines
kernel/power/snapshot.c +3 -3
        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!

maintainer
#2 lore raw
In reply to Brian Geffon
Quoted 8 lines · Brian Geffon

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 <[email protected]>
Fixes 8357376 ("swsusp: Improve handling of highmem")
Cc [email protected]

Change-Id: Ibb43a9b4ac5ff2d7e3021fdacc08e116650231e9

Please always use checkpatch.pl so that maintainers don't have to ask you to use checkpatch.pl :(