[PATCH v2 net] octeontx2-pf: fix NULL deref of af_xdp_zc_qidx on rep setup

[Ratheesh Kannoth]

From: Suman Ghosh <sumang@xxxxxxxxxxx>

af_xdp_zc_qidx tracks receive queues using AF_XDP zero-copy and is
allocated during PF/VF probe. Representors and other non-AF_XDP paths
leave the pointer NULL, but several call sites used test_bit() on it
unconditionally.

Switching to devlink eswitch mode creates representors and runs
otx2_init_hw_resources(), which reaches otx2_pool_aq_init() and oopses
when dereferencing the NULL bitmap. Add NULL checks before every
af_xdp_zc_qidx test_bit() use in the RSS, ethtool, XSK, and pool init
paths.

Fixes: efabce290151 ("octeontx2-pf: AF_XDP zero copy receive support")
Signed-off-by: Suman Ghosh <sumang@xxxxxxxxxxx>
Signed-off-by: Geetha sowjanya <gakula@xxxxxxxxxxx>
Signed-off-by: Ratheesh Kannoth <rkannoth@xxxxxxxxxxx>

---
v1 -> v2: Addressed sashiko comments
	https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260820090533.2681578-1-rkannoth%40marvell.com
---
 drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c  | 6 ++++--
 drivers/net/ethernet/marvell/octeontx2/nic/otx2_ethtool.c | 3 ++-
 drivers/net/ethernet/marvell/octeontx2/nic/otx2_xsk.c     | 3 ++-
 3 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
index ca73a94db794..175992188c18 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
@@ -333,7 +333,8 @@ int otx2_set_rss_table(struct otx2_nic *pfvf, int ctx_id, const u32 *ind_tbl)
 	/* Get memory to put this msg */
 	for (idx = 0; idx < rss->rss_size; idx++) {
 		/* Ignore the queue if AF_XDP zero copy is enabled */
-		if (test_bit(ind_tbl[idx], pfvf->af_xdp_zc_qidx))
+		if (pfvf->af_xdp_zc_qidx &&
+		    test_bit(ind_tbl[idx], pfvf->af_xdp_zc_qidx))
 			continue;
 
 		aq = otx2_mbox_alloc_msg_nix_aq_enq(mbox);
@@ -1509,7 +1510,8 @@ int otx2_pool_aq_init(struct otx2_nic *pfvf, u16 pool_id,
 	if (type != AURA_NIX_RQ)
 		return 0;
 
-	if (!test_bit(pool_id, pfvf->af_xdp_zc_qidx)) {
+	if (!pfvf->af_xdp_zc_qidx ||
+	    !test_bit(pool_id, pfvf->af_xdp_zc_qidx)) {
 		pp_params.order = get_order(buf_size);
 		pp_params.flags = PP_FLAG_DMA_MAP;
 		pp_params.pool_size = min(OTX2_PAGE_POOL_SZ, numptrs);
diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_ethtool.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_ethtool.c
index a0340f3422bf..9bee1b91eeaa 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_ethtool.c
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_ethtool.c
@@ -939,7 +939,8 @@ static int otx2_get_rxfh(struct net_device *dev,
 
 	for (idx = 0; idx < rss->rss_size; idx++) {
 		/* Ignore if the rx queue is AF_XDP zero copy enabled */
-		if (test_bit(rss->ind_tbl[idx], pfvf->af_xdp_zc_qidx))
+		if (pfvf->af_xdp_zc_qidx &&
+		    test_bit(rss->ind_tbl[idx], pfvf->af_xdp_zc_qidx))
 			continue;
 		indir[idx] = rss->ind_tbl[idx];
 	}
diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_xsk.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_xsk.c
index 7d67b4cbaf71..0e8a6a6486c4 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_xsk.c
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_xsk.c
@@ -193,7 +193,8 @@ int otx2_xsk_wakeup(struct net_device *dev, u32 queue_id, u32 flags)
 
 void otx2_attach_xsk_buff(struct otx2_nic *pfvf, struct otx2_snd_queue *sq, int qidx)
 {
-	if (test_bit(qidx, pfvf->af_xdp_zc_qidx))
+	if (pfvf->af_xdp_zc_qidx &&
+	    test_bit(qidx, pfvf->af_xdp_zc_qidx))
 		sq->xsk_pool = xsk_get_pool_from_qid(pfvf->netdev, qidx);
 }
 
-- 
2.43.0