linux-kernel - [PATCH RESEND] qed: Move a variable assignment behind a null pointer check in two functions

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Message-ID: <6958583a-77c0-41ca-8f80-7ff647b385bb@web.de>
Date: Sun, 2 Mar 2025 17:55:40 +0100
From: Markus Elfring <Markus.Elfring@....de>
To: kernel-janitors@...r.kernel.org, netdev@...r.kernel.org,
 Andrew Lunn <andrew+netdev@...n.ch>, Ariel Elior <aelior@...vell.com>,
 "David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>,
 Jakub Kicinski <kuba@...nel.org>, Manish Chopra <manishc@...vell.com>,
 Paolo Abeni <pabeni@...hat.com>, Ram Amrani <Ram.Amrani@...iumnetworks.com>,
 Yuval Mintz <Yuval.Mintz@...iumnetworks.com>
Cc: cocci@...ia.fr, LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH RESEND] qed: Move a variable assignment behind a null pointer
 check in two functions

From: Markus Elfring <elfring@...rs.sourceforge.net>
Date: Tue, 11 Apr 2023 19:33:53 +0200

The address of a data structure member was determined before
a corresponding null pointer check in the implementation of
the functions “qed_ll2_rxq_completion” and “qed_ll2_txq_completion”.

Thus avoid the risk for undefined behaviour by moving the assignment
for the variables “p_rx” and “p_tx” behind the null pointer check.

This issue was detected by using the Coccinelle software.

Fixes: 0a7fb11c23c0 ("qed: Add Light L2 support")
Signed-off-by: Markus Elfring <elfring@...rs.sourceforge.net>
---
 drivers/net/ethernet/qlogic/qed/qed_ll2.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/qlogic/qed/qed_ll2.c b/drivers/net/ethernet/qlogic/qed/qed_ll2.c
index 717a0b3f89bd..941c02fccaaf 100644
--- a/drivers/net/ethernet/qlogic/qed/qed_ll2.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_ll2.c
@@ -346,7 +346,7 @@ static void qed_ll2_txq_flush(struct qed_hwfn *p_hwfn, u8 connection_handle)
 static int qed_ll2_txq_completion(struct qed_hwfn *p_hwfn, void *p_cookie)
 {
 	struct qed_ll2_info *p_ll2_conn = p_cookie;
-	struct qed_ll2_tx_queue *p_tx = &p_ll2_conn->tx_queue;
+	struct qed_ll2_tx_queue *p_tx;
 	u16 new_idx = 0, num_bds = 0, num_bds_in_packet = 0;
 	struct qed_ll2_tx_packet *p_pkt;
 	bool b_last_frag = false;
@@ -356,6 +356,7 @@ static int qed_ll2_txq_completion(struct qed_hwfn *p_hwfn, void *p_cookie)
 	if (!p_ll2_conn)
 		return rc;

+	p_tx = &p_ll2_conn->tx_queue;
 	spin_lock_irqsave(&p_tx->lock, flags);
 	if (p_tx->b_completing_packet) {
 		rc = -EBUSY;
@@ -523,7 +524,7 @@ qed_ll2_rxq_handle_completion(struct qed_hwfn *p_hwfn,
 static int qed_ll2_rxq_completion(struct qed_hwfn *p_hwfn, void *cookie)
 {
 	struct qed_ll2_info *p_ll2_conn = (struct qed_ll2_info *)cookie;
-	struct qed_ll2_rx_queue *p_rx = &p_ll2_conn->rx_queue;
+	struct qed_ll2_rx_queue *p_rx;
 	union core_rx_cqe_union *cqe = NULL;
 	u16 cq_new_idx = 0, cq_old_idx = 0;
 	unsigned long flags = 0;
@@ -532,6 +533,7 @@ static int qed_ll2_rxq_completion(struct qed_hwfn *p_hwfn, void *cookie)
 	if (!p_ll2_conn)
 		return rc;

+	p_rx = &p_ll2_conn->rx_queue;
 	spin_lock_irqsave(&p_rx->lock, flags);

 	if (!QED_LL2_RX_REGISTERED(p_ll2_conn)) {
--
2.40.0