[PATCH v2 2/2] mm/memfd_luo: release preserved folios when retrieve fails

[sashiko-bot at kernel.org]

> retrieve() only frees the serialization structure on its error paths, but
> the folios it describes are still preserved at that point:
> memfd_luo_finish() deliberately skips its own cleanup for records whose
> retrieve() failed, since it relies on retrieve() to have released them.
> The folios and the folio array are therefore never handed back and stay
> reserved in the next kernel.
> 
> Release them from retrieve() as well, by sharing the cleanup with
> memfd_luo_finish().  After the record has been validated, the folio array
> is restored before the file is allocated, so a failure from
> memfd_alloc_file() or memfd_add_seals() can release the folios directly
> instead of allocating memory while already handling a failure; a record
> this version does not support is rejected before that and uses the shared
> cleanup too.  The folios may only be released while they are still fully
> preserved: once memfd_luo_retrieve_folios() has run it has consumed every
> [ ... ]
> by Sashiko AI review).
> 
> Fixes: f85b1c6af5bc ("liveupdate: luo_file: remember retrieve() status")
> Assisted-by: Pi:glm-5.3-flash
> Signed-off-by: Haolong Wang <18766350203 at 163.com>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261014031254.432582-1-18766350203@163.com?part=2