xdp_rxq_info_unreg() implicitly calls xdp_rxq_info_unreg_mem_model().
This may well be confusing to the driver authors, and lead to double
free if they call xdp_rxq_info_unreg_mem_model() before
xdp_rxq_info_unreg() (when mem model type == MEM_TYPE_PAGE_POOL).
In fact error path of mvpp2_rxq_init() seems to currently do
exactly that.
The double free will result in refcount underflow
in page_pool_destroy(). Make the interface a little more
programmer friendly by clearing type and id so that
xdp_rxq_info_unreg_mem_model() can be called multiple
times.
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
---
Targeting bpf-next, the mvpp2 bug (if it's real) can be addressed
separately. IMHO it may be a little late in the cycle for
"API convenience" changes but I tested against bpf as well.
net/core/xdp.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/net/core/xdp.c b/net/core/xdp.c
index 858276e72c68..6ea3302c42eb 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -113,8 +113,13 @@ static void mem_allocator_disconnect(void *allocator)
void xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq)
{
struct xdp_mem_allocator *xa;
+ int type = xdp_rxq->mem.type;
int id = xdp_rxq->mem.id;
+ /* Reset mem info to defaults */
+ xdp_rxq->mem.id = 0;
+ xdp_rxq->mem.type = 0;
+
if (xdp_rxq->reg_state != REG_STATE_REGISTERED) {
WARN(1, "Missing register, driver bug");
return;
@@ -123,7 +128,7 @@ void xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq)
if (id == 0)
return;
- if (xdp_rxq->mem.type == MEM_TYPE_PAGE_POOL) {
+ if (type == MEM_TYPE_PAGE_POOL) {
rcu_read_lock();
xa = rhashtable_lookup(mem_id_ht, &id, mem_id_rht_params);
page_pool_destroy(xa->page_pool);
@@ -144,10 +149,6 @@ void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq)
xdp_rxq->reg_state = REG_STATE_UNREGISTERED;
xdp_rxq->dev = NULL;
-
- /* Reset mem info to defaults */
- xdp_rxq->mem.id = 0;
- xdp_rxq->mem.type = 0;
}
EXPORT_SYMBOL_GPL(xdp_rxq_info_unreg);
--
2.31.1
