Re: [PATCH 2/2] liveupdate: Remember FLB retrieve() status

[Pratyush Yadav <pratyush@kernel.org>]

On Thu, May 28 2026, David Matlack wrote:

> LUO keeps track of successful retrieve attempts on an FLB. It does so
> to avoid multiple retrievals of the same FLB. Multiple retrievals cause
> problems because once the FLB is retrieved, the serialized data
> structures are likely freed and the FLB is likely in a very different
> state from what the code expects.
>
> All this works well when retrieve succeeds. When it fails,
> luo_flb_retrieve_one() returns the error immediately, without ever
> storing anywhere that a retrieve was attempted or what its error code
> was. If the user attempts to retrieve another file registered with the
> same FLB, LUO will attempt to call the FLB's retrieve() callback again.
>
> The retry is problematic for much of the same reasons listed above. The
> FLB is likely in a very different state than what the retrieve logic
> normally expects (e.g. some KHO pages may have already been restored and
> freed).
>
> There is no sane way of attempting the retrieve again. Remember the
> error retrieve returned and directly return it on a retry.
>
> This is done by changing the retrieved bool to a retrieve_status
> integer. A value of 0 means retrieve was never attempted, a positive
> value means it succeeded, and a negative value means it failed and the
> error code is the value.
>
> This is similar to commit f85b1c6af5bc ("liveupdate: luo_file: remember
> retrieve() status") which did the same for LUO files.
>
> Fixes: cab056f2aae7 ("liveupdate: luo_flb: introduce File-Lifecycle-Bound global state")
> Assisted-by: Gemini:gemini-3-pro-preview
> Signed-off-by: David Matlack <dmatlack@google.com>

Reviewed-by: Pratyush Yadav (Google) <pratyush@kernel.org>

Thanks for fixing this!

[...]

-- 
Regards,
Pratyush Yadav