path: root/net/xdp
diff options
authorMagnus Karlsson <magnus.karlsson@intel.com>2018-06-29 09:48:17 +0200
committerAlexei Starovoitov <ast@kernel.org>2018-07-02 18:37:11 -0700
commit20b52a75166086a40d838397ef3db28a4f2c5998 (patch)
tree5c6f0af2b630f695698e9c08459bad13d8abff26 /net/xdp
parentMerge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md (diff)
xsk: fix potential lost completion message in SKB path
The code in xskq_produce_addr erroneously checked if there was up to LAZY_UPDATE_THRESHOLD amount of space in the completion queue. It only needs to check if there is one slot left in the queue. This bug could under some circumstances lead to a WARN_ON_ONCE being triggered and the completion message to user space being lost. Fixes: 35fcde7f8deb ("xsk: support for Tx") Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Reported-by: Pavel Odintsov <pavel@fastnetmon.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'net/xdp')
1 files changed, 2 insertions, 7 deletions
diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h
index ef6a6f0ec949..52ecaf770642 100644
--- a/net/xdp/xsk_queue.h
+++ b/net/xdp/xsk_queue.h
@@ -62,14 +62,9 @@ static inline u32 xskq_nb_avail(struct xsk_queue *q, u32 dcnt)
return (entries > dcnt) ? dcnt : entries;
-static inline u32 xskq_nb_free_lazy(struct xsk_queue *q, u32 producer)
- return q->nentries - (producer - q->cons_tail);
static inline u32 xskq_nb_free(struct xsk_queue *q, u32 producer, u32 dcnt)
- u32 free_entries = xskq_nb_free_lazy(q, producer);
+ u32 free_entries = q->nentries - (producer - q->cons_tail);
if (free_entries >= dcnt)
return free_entries;
@@ -129,7 +124,7 @@ static inline int xskq_produce_addr(struct xsk_queue *q, u64 addr)
struct xdp_umem_ring *ring = (struct xdp_umem_ring *)q->ring;
- if (xskq_nb_free(q, q->prod_tail, LAZY_UPDATE_THRESHOLD) == 0)
+ if (xskq_nb_free(q, q->prod_tail, 1) == 0)
return -ENOSPC;
ring->desc[q->prod_tail++ & q->ring_mask] = addr;