Le jeu. 11 juin 2026, 18:01, Morten Brørup <[email protected]> a écrit :
> > From: Maxime Leroy [mailto:[email protected]] On Behalf Of Maxime > > Leroy > > Sent: Thursday, 11 June 2026 17.49 > > > > eth_dev_fp_ops_reset() restores a port's fast-path ops on stop/release > > via a compound literal, so every field it omits is zeroed to NULL. It > > sets only rx_pkt_burst/tx_pkt_burst (and the rxq/txq data), leaving > > rx_queue_count, tx_queue_count, rx/tx_descriptor_status, tx_pkt_prepare > > and the recycle callbacks NULL. > > > > In non-debug builds these ops are reached through an unguarded indirect > > call (the NULL check exists only under RTE_ETHDEV_DEBUG_RX/TX). So a > > thread calling e.g. rte_eth_rx_queue_count() on a port being stopped > > dereferences NULL and crashes, while the same race on > > rte_eth_rx_burst() > > is harmless because the burst ops are reset to dummies. A poll-mode > > worker re-checking rx_queue_count before arming the Rx interrupt and > > sleeping hits exactly this. > > > > Reset these ops to the same dummies eth_dev_set_dummy_fops() installs, > > so a stopped port behaves like a freshly allocated one: every fast-path > > op is a safe no-op, none is NULL. > > > > Fixes: 066f3d9cc21c ("ethdev: remove callback checks from fast path") > > Cc: [email protected] > > Signed-off-by: Maxime Leroy <[email protected]> > > --- > > Good catch. > Acked-by: Morten Brørup <[email protected]> > > Not related to the series, consider sending as separate patch. > Thanks for the review and Ack. Agreed, this is a generic ethdev fix. I kept it in this series because the NAPI user depends on it. The current Grout NAPI loop arms RX queue interrupts and then re-checks rte_eth_rx_queue_count() before blocking, to avoid sleeping when a packet arrived between the last empty poll and epoll_wait. With the current ethdev reset path, rx_burst is replaced by a dummy callback on stop/release, but rx_queue_count becomes NULL. So if the port is stopped concurrently, the NAPI worker dereferences a NULL function pointer and segfaults on that recheck. I can split it out if maintainers prefer, but then the dpaa2 NAPI series has a real dependency on the standalone ethdev fix. >
