Re: [PATCH v5 net] net: page_pool: fix UAF in __page_pool_release_netmem_dma on xa_cmpxchg race

[Jakub Kicinski]

On Fri, 7 Aug 2026 19:48:30 +0800 Jijie Shao wrote:
> This bug was discovered while testing the hns3 driver under channel
> reconfiguration (`ethtool -L` / `ethtool -G`) with iperf3 traffic on
> arm64. The race is intermittently triggered when page_pool_destroy()
> runs page_pool_scrub() concurrently with page return via
> page_pool_put_netmem() on a different CPU. A WARN in
> page_pool_clear_pp_info() surfaced the dangling DMA index bits left
> by the cmpxchg loser, which led to the investigation.

LGTM, we'll apply on Thu, after the final PR for this release.
I don't think the risk / benefit ratio is here for final.