Re: [PATCH v5 net] net: page_pool: fix UAF in __page_pool_release_netmem_dma on xa_cmpxchg race
Jakub Kicinski <[email protected]>
| Newsgroups | org.kernel.vger.netdev,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
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.