[PATCH net] net/packet: ignore timestamp bits when testing tx frame status
WARM1d
From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Date: 2026-10-04 17:18:55
Subsystem:
networking [general], packet sockets, the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Willem de Bruijn, Linus Torvalds
From: Willem de Bruijn <willemb@google.com>
Since the commit in Fixes, the tx completion handler writes the frame
status as TP_STATUS_AVAILABLE | ts, where ts can be
TP_STATUS_TS_SOFTWARE or TP_STATUS_TS_RAW_HARDWARE.
Two places compare a tx frame status to TP_STATUS_AVAILABLE for
equality, and so fail to detect such a released frame:
- tpacket_snd(), when packet_xmit() fails: the packet is silently
dropped instead of an error being returned to the caller for retry.
- packet_poll(), on the tx ring head frame: the socket is not reported
as writable.
Mask out the timestamp bits in both. In packet_lookup_frame(), only do
so when testing a tx ring frame for TP_STATUS_AVAILABLE.
Fixes: b9c32fb27170 ("packet: if hw/sw ts enabled in rx/tx ring, report which ts we got")
Signed-off-by: Willem de Bruijn <willemb@google.com>
---
net/packet/af_packet.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 6ff16eef24f4..1cabe292ebb4 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c@@ -398,6 +398,10 @@ static inline struct page * __pure pgv_to_page(void *addr) return virt_to_page(addr); } +/* Timestamp bits that may be set in addition to the frame state */ +static const u32 tp_status_ts_mask = TP_STATUS_TS_SOFTWARE | + TP_STATUS_TS_RAW_HARDWARE; + static void __packet_set_status(struct packet_sock *po, void *frame, int status) { union tpacket_uhdr h;
@@ -519,6 +523,7 @@ static void *packet_lookup_frame(const struct packet_sock *po, { unsigned int pg_vec_pos, frame_offset; union tpacket_uhdr h; + u32 mask = 0; pg_vec_pos = position / rb->frames_per_block; frame_offset = position % rb->frames_per_block;
@@ -526,7 +531,10 @@ static void *packet_lookup_frame(const struct packet_sock *po, h.raw = rb->pg_vec[pg_vec_pos].buffer + (frame_offset * rb->frame_size); - if (status != __packet_get_status(po, h.raw)) + if (rb == &po->tx_ring && status == TP_STATUS_AVAILABLE) + mask = tp_status_ts_mask; + + if (status != (__packet_get_status(po, h.raw) & ~mask)) return NULL; return h.raw;
@@ -2948,7 +2956,7 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg) if (unlikely(err != 0)) { if (err > 0) err = net_xmit_errno(err); - if (err && __packet_get_status(po, ph) == + if (err && (__packet_get_status(po, ph) & ~tp_status_ts_mask) == TP_STATUS_AVAILABLE) { /* skb was destructed already */ skb = NULL;
--
2.56.0.rc1.315.gc6ed9934b7-goog