Re: [PATCH RFC batadv] batman-adv: bla: fix report_work leak on backbone_gw purge

[Simon Wunderlich <sw@simonwunderlich.de>]

On Sunday, May 10, 2026 12:03:42 PM Central European Summer Time Sven 
Eckelmann wrote:
> batadv_bla_purge_backbone_gw() removes stale backbone gateway entries,
> but fails to properly handle their associated report_work:
> 
> - If report_work is running, the purge must wait for it to finish before
>   freeing the backbone_gw, otherwise the worker may access freed memory
>   (e.g. bat_priv).
> - If report_work is pending, the purge must cancel it and release the
>   reference held for that pending work item.
> 
> The previous implementation called hlist_for_each_entry_safe() inside a
> spin_lock_bh() section, but cancel_work_sync() may sleep and therefore
> cannot be called from within a spinlock-protected region.
> 
> Restructure the loop to handle one entry per spinlock critical section:
> acquire the lock, find the next entry to purge, remove it from the hash
> list, then release the lock before calling cancel_work_sync() and
> dropping the hash_entry reference. Repeat until no more entries require
> purging.
> 
> Fixes: a998bf5dfbd7 ("batman-adv: add detection for complex bridge loops")
> Signed-off-by: Sven Eckelmann <sven@narfation.org>

This looks good, thank you!

Reviewed-by: Simon Wunderlich <sw@simonwunderlich.de>

Cheers,
       Simon