[PATCH net] octeontx2-af: fix NULL deref in NIX TM tree debugfs read path

[Ratheesh Kannoth <rkannoth@marvell.com>]

From: Anshumali Gaur <agaur@marvell.com>

rvu_dbg_nix_tm_tree_display() dereferences pfvf->sq_ctx without
checking whether the SQ context has been allocated. Reading
/sys/kernel/debug/octeontx2/nix/tm_tree for a NIX LF whose transmit
queues are not set up triggers a kernel oops.

Guard the read path the same way rvu_dbg_nix_tm_tree_write() already
does and return -EINVAL with a seq_file message when sq_ctx is NULL.

Fixes: b907194a5d5b ("octeontx2-af: Add debugfs support to dump NIX TM topology")
Signed-off-by: Anshumali Gaur <agaur@marvell.com>
Signed-off-by: Ratheesh Kannoth <rkannoth@marvell.com>
---
 drivers/net/ethernet/marvell/octeontx2/af/rvu_debugfs.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/ethernet/marvell/octeontx2/af/rvu_debugfs.c b/drivers/net/ethernet/marvell/octeontx2/af/rvu_debugfs.c
index 3456313d3b3c..22ee99676879 100644
--- a/drivers/net/ethernet/marvell/octeontx2/af/rvu_debugfs.c
+++ b/drivers/net/ethernet/marvell/octeontx2/af/rvu_debugfs.c
@@ -1697,6 +1697,12 @@ static int rvu_dbg_nix_tm_tree_display(struct seq_file *m, void *unused)
 		return -EINVAL;
 
 	pfvf = rvu_get_pfvf(rvu, pcifunc);
+
+	if (!pfvf->sq_ctx) {
+		seq_printf(m, "SQ context is not initialized for pcifunc 0x%x\n", pcifunc);
+		return -EINVAL;
+	}
+
 	max_id = pfvf->sq_ctx->qsize;
 
 	memset(&aq_req, 0, sizeof(struct nix_aq_enq_req));
-- 
2.43.0