[PATCH -next] PM: hibernate: add retry mechanism for S4 image loading failures

[Xueqin Luo]

During the S4 resume process, there's a rare chance of image loading
failure. We provide three retries to load it successfully. If the
recovery fails after these attempts, print out the handle CRC32
value. When the CRC32 value obtained on each retry are inconsistent,
there may be a memory anomaly. When the values are consistent, it
might indicate corrupted swapped memory data.

Signed-off-by: Xueqin Luo <luoxueqin@xxxxxxxxxx>
---
 kernel/power/hibernate.c |  8 ++++++++
 kernel/power/swap.c      | 14 ++++++++------
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index 43b1a82e800c..d9bcf38221ef 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -703,6 +703,7 @@ static int load_image_and_restore(void)
 {
 	int error;
 	unsigned int flags;
+	int cnt = 0;
 
 	pm_pr_dbg("Loading hibernation image.\n");
 
@@ -713,7 +714,14 @@ static int load_image_and_restore(void)
 		goto Unlock;
 	}
 
+retry:
 	error = swsusp_read(&flags);
+	if (error && (cnt++ < 3)) {
+		pr_err("Failed to load hibernation image, trying to load again...\n");
+		swsusp_free();
+		goto retry;
+	}
+
 	swsusp_close();
 	if (!error)
 		error = hibernation_restore(flags & SF_PLATFORM_MODE);
diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index 5bc04bfe2db1..4b866c645cd7 100644
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -1489,15 +1489,17 @@ static int load_compressed_image(struct swap_map_handle *handle,
 		ret = snapshot_write_finalize(snapshot);
 		if (!ret && !snapshot_image_loaded(snapshot))
 			ret = -ENODATA;
-		if (!ret) {
-			if (swsusp_header->flags & SF_CRC32_MODE) {
-				if(handle->crc32 != swsusp_header->crc32) {
-					pr_err("Invalid image CRC32!\n");
-					ret = -ENODATA;
-				}
+	}
+	if (!ret) {
+		if (swsusp_header->flags & SF_CRC32_MODE) {
+			if (handle->crc32 != swsusp_header->crc32) {
+				pr_err("Invalid image CRC32, swsusp header CRC32: %u, handle CRC32: %u\n",
+					 swsusp_header->crc32, handle->crc32);
+				ret = -ENODATA;
 			}
 		}
 	}
+
 	swsusp_show_speed(start, stop, nr_to_read, "Read");
 out_clean:
 	hib_finish_batch(&hb);
-- 
2.25.1