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

From: Pavel Machek
Date: Wed May 01 2024 - 02:25:04 EST


> 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>

NAK. If machine is so broken it can't load memory image, it is not
safe to continue.

Pavel
> ---
> 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