Re: [PATCH v3 0/4] PM: hibernate: flush icache for restored pages from task context

[Rafael J. Wysocki (Intel)]

On Fri, Oct 2, 2026 at 5:42 AM Xiong Xin <xiongxin@xxxxxxxxxx> wrote:
>
> Hello,
>
> With `hibernate=nocompress`, load_image() submits the read bios
> asynchronously and hib_end_io() completes them from hardirq/softirq
> context.  The flush_icache_range() call there, added by the
> commit f6cf0545ec69 ("PM / Hibernate: Call flush_icache_range() on pages
> restored in-place"), ends with kick_all_cpus_sync() on ARM64 and so
> triggers the WARN_ON_ONCE(!in_task()) in smp_call_function().
>
> This series fixes it by keeping the flush in task context, and first
> closes three pre-existing holes in the restore error paths that the
> rework would otherwise trip over.
>
> Patch 1 resets clean_pages_on_read when load_image() finishes, so that
> a failed nocompress resume can no longer leak the flag into a later
> compressed resume, where it made hib_end_io() call flush_icache_range()
> from interrupt context for the reused ring pages of
> load_compressed_image().  The flag is also cleared as soon as the load
> is known to have failed, so that the bios still in flight do not flush
> from interrupt context during the final drain.
>
> Patch 2 stops snapshot_write_next() from releasing all snapshot pages
> in place when one of its internal allocations fails: the read bios do
> not take page references, so freed pages could be handed out again
> while the device is still writing the image data into them.  The image
> is now released by the outer error paths, after swsusp_read() has
> drained the batch.
>
> Patch 3 makes the error exits of load_compressed_image() wait for the
> read bios that may still be in flight before the ring pages are freed,
> like save_compressed_image() and load_image() already do.
>
> Patch 4 defers the flush on the nocompress path: hib_end_io() now only
> records the restored page on a per-batch list, and load_image() flushes
> the pages once hib_wait_io() has returned, preserving the asynchronous
> batched I/O.
>
> Patches 1 to 3 are new in v3; the per-patch changelogs are in the ---
> sections of each commit.  Many thanks to sashiko for the v2 review,
> both findings are addressed.
>
> Xiong Xin (4):
>   PM: hibernate: reset clean_pages_on_read after load_image()
>   PM: hibernate: do not free the image in place while restore I/O is in
>     flight
>   PM: hibernate: drain pending reads in compressed image load errors
>   PM: hibernate: flush icache for restored pages from task context
>
>  kernel/power/snapshot.c |  9 ++-----
>  kernel/power/swap.c     | 55 +++++++++++++++++++++++++++++++++++------
>  2 files changed, 50 insertions(+), 14 deletions(-)
>
> --

Sashiko is complaining about the last patch in this series:

https://sashiko.dev/#/patchset/20261002034200.920546-1-xiongxin%40kylinos.cn

Please address the issue flagged by it or let me know if that is not a
real problem.

In either case, please send the series once again.