[PATCH v2 net] octeontx2-af: npc: Fix size of entry2cntr_map

[Ratheesh Kannoth <rkannoth@marvell.com>]

KASAN prints below splat. This is caused by allocating counter for
reserved mcam entry for cpt 2nd pass entry. But mcam->entry2cntr_map
is not allocated for reserved entries.

BUG: KASAN: slab-out-of-bounds in npc_map_mcam_entry_and_cntr+0xb0/0x1a0
Write of size 2 at addr ffff0001033e7ffe by task kworker/0:1/14

CPU: 0 PID: 14 Comm: kworker/0:1 Not tainted 6.1.67 #1
Hardware name: Marvell CN106XX board (DT)
Workqueue: events work_for_cpu_fn
Call trace:
 dump_backtrace.part.0+0xe4/0xf0
 show_stack+0x18/0x30
 dump_stack_lvl+0x88/0xb4
 print_report+0x154/0x458
 kasan_report+0xb8/0x194
 __asan_store2+0x7c/0xa0
 npc_map_mcam_entry_and_cntr+0xb0/0x1a0
 rvu_mbox_handler_npc_mcam_write_entry+0x268/0x280
 npc_install_flow+0x840/0xfe0
 rvu_npc_install_cpt_pass2_entry+0x138/0x190
 rvu_nix_init+0x148c/0x2880
 rvu_probe+0x1800/0x30b0
 local_pci_probe+0x78/0xe0
 work_for_cpu_fn+0x30/0x50
 process_one_work+0x4cc/0x97c
 worker_thread+0x360/0x630
 kthread+0x1a0/0x1b0
 ret_from_fork+0x10/0x20

Fixes: 55307fcb9258 ("octeontx2-af: Add mbox messages to install and delete MCAM rules")
Cc: Subbaraya Sundeep <sbhatta@marvell.com>
Signed-off-by: Ratheesh Kannoth <rkannoth@marvell.com>
---
 .../ethernet/marvell/octeontx2/af/rvu_npc.c   | 40 +++++++------------
 1 file changed, 15 insertions(+), 25 deletions(-)

diff --git a/drivers/net/ethernet/marvell/octeontx2/af/rvu_npc.c b/drivers/net/ethernet/marvell/octeontx2/af/rvu_npc.c
index d301a3f0f87a..4994385a822b 100644
--- a/drivers/net/ethernet/marvell/octeontx2/af/rvu_npc.c
+++ b/drivers/net/ethernet/marvell/octeontx2/af/rvu_npc.c
@@ -2181,7 +2181,7 @@ int npc_mcam_rsrcs_init(struct rvu *rvu, int blkaddr)
 	/* Alloc memory for MCAM entry to counter mapping and for tracking
 	 * counter's reference count.
 	 */
-	mcam->entry2cntr_map = kcalloc(mcam->bmap_entries, sizeof(u16),
+	mcam->entry2cntr_map = kcalloc(mcam->total_entries, sizeof(u16),
 				       GFP_KERNEL);
 	if (!mcam->entry2cntr_map)
 		goto free_cntr_map;
@@ -2197,10 +2197,11 @@ int npc_mcam_rsrcs_init(struct rvu *rvu, int blkaddr)
 	if (!mcam->entry2target_pffunc)
 		goto free_cntr_refcnt;

-	for (index = 0; index < mcam->bmap_entries; index++) {
+	for (index = 0; index < mcam->bmap_entries; index++)
 		mcam->entry2pfvf_map[index] = NPC_MCAM_INVALID_MAP;
+
+	for (index = 0; index < mcam->total_entries; index++)
 		mcam->entry2cntr_map[index] = NPC_MCAM_INVALID_MAP;
-	}

 	for (cntr = 0; cntr < mcam->counters.max; cntr++)
 		mcam->cntr2pfvf_map[cntr] = NPC_MCAM_INVALID_MAP;
@@ -3531,7 +3532,7 @@ static int __npc_mcam_free_counter(struct rvu *rvu,
 				   struct msg_rsp *rsp)
 {
 	struct npc_mcam *mcam = &rvu->hw->mcam;
-	u16 index, entry = 0;
+	u16 index;
 	int blkaddr, err;

 	blkaddr = rvu_get_blkaddr(rvu, BLKTYPE_NPC, 0);
@@ -3547,20 +3548,16 @@ static int __npc_mcam_free_counter(struct rvu *rvu,
 	mcam->cntr2pfvf_map[req->cntr] = NPC_MCAM_INVALID_MAP;
 	rvu_free_rsrc(&mcam->counters, req->cntr);

-	/* Disable all MCAM entry's stats which are using this counter */
-	while (entry < mcam->bmap_entries) {
+	/* Disable all MCAM entry's stats which are using this counter.
+	 * Scan the full MCAM index range: AF-reserved rules (e.g. CPT pass-2)
+	 */
+	for (index = 0; index < mcam->total_entries; index++) {
 		if (!mcam->cntr_refcnt[req->cntr])
 			break;
-
-		index = find_next_bit(mcam->bmap, mcam->bmap_entries, entry);
-		if (index >= mcam->bmap_entries)
-			break;
-		entry = index + 1;
 		if (mcam->entry2cntr_map[index] != req->cntr)
 			continue;
-
-		npc_unmap_mcam_entry_and_cntr(rvu, mcam, blkaddr,
-					      index, req->cntr);
+		npc_unmap_mcam_entry_and_cntr(rvu, mcam, blkaddr, index,
+					      req->cntr);
 	}

 	return 0;
@@ -3631,7 +3628,7 @@ int rvu_mbox_handler_npc_mcam_unmap_counter(struct rvu *rvu,
 		struct npc_mcam_unmap_counter_req *req, struct msg_rsp *rsp)
 {
 	struct npc_mcam *mcam = &rvu->hw->mcam;
-	u16 index, entry = 0;
+	u16 index;
 	int blkaddr, rc;

 	/* Counter is not supported for CN20K */
@@ -3658,20 +3655,13 @@ int rvu_mbox_handler_npc_mcam_unmap_counter(struct rvu *rvu,
 	}

 	/* Disable all MCAM entry's stats which are using this counter */
-	while (entry < mcam->bmap_entries) {
+	for (index = 0; index < mcam->total_entries; index++) {
 		if (!mcam->cntr_refcnt[req->cntr])
 			break;
-
-		index = find_next_bit(mcam->bmap, mcam->bmap_entries, entry);
-		if (index >= mcam->bmap_entries)
-			break;
-		entry = index + 1;
-
 		if (mcam->entry2cntr_map[index] != req->cntr)
 			continue;
-
-		npc_unmap_mcam_entry_and_cntr(rvu, mcam, blkaddr,
-					      index, req->cntr);
+		npc_unmap_mcam_entry_and_cntr(rvu, mcam, blkaddr, index,
+					      req->cntr);
 	}
 exit:
 	mutex_unlock(&mcam->lock);
--
2.43.0

--
v1 -> v2: Addressed Jakub comments
	https://lore.kernel.org/netdev/20260605055839.3549559-1-rkannoth@marvell.com/