Re: [PATCH v4 06/19] liveupdate: Don't WARN if tracking a retrieved file fails

[sashiko-bot@kernel.org]

> Handle a failure to add a retrieved file to luo_preserved_files instead
> of triggering a WARN_ON(). Make the failure permanent, and keep the file
> until the file set is finished, like any other retrieved file. Only warn
> if the file is already tracked (-EBUSY), which would be a kernel bug,
> since a retrieved file is always a new file.
> 
> xa_insert() can fail with -ENOMEM, and userspace can trigger that with
> LIVEUPDATE_SESSION_RETRIEVE_FD, so warning about it lets userspace crash
> systems with panic_on_warn.
> 
> The handler has already consumed the preserved state when this happens,
> so the retrieve can't be retried. Keeping the file ensures that its
> resources are not released before the file set is finished. Finishing
> the file set then erases the file from luo_preserved_files, which does
> nothing for a file that was never added.
> 
> Fixes: 00d0b372374f ("liveupdate: prevent double management of files")
> Signed-off-by: David Matlack <dmatlack@google.com>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261111002358.1842967-1-dmatlack@google.com?part=6