[PATCH v2] bnx2x: fix NULL pointer dereference in bnx2x_free_mem_bp()

Jiangshan Yi <[email protected]>
Newsgroups org.kernel.vger.netdev,org.kernel.vger.linux-kernel,org.kernel.vger.stable
Message-ID <[email protected]>
bnx2x_alloc_mem_bp() sets bp->fp_array_size before allocating bp->fp.
If the fp allocation fails, the error path calls bnx2x_free_mem_bp(),
which dereferences bp->fp in a loop bounded by the non-zero
bp->fp_array_size, causing a NULL pointer dereference.

Move the bp->fp_array_size assignment to after bp->fp is set so that
the loop in bnx2x_free_mem_bp() naturally becomes a no-op when bp->fp
is NULL, since bp is zero-initialized and fp_array_size remains 0.

Fixes: c3146eb676e7c ("bnx2x: Correct memory preparation and release")
Reported-by: Sashiko <[email protected]>
Closes: https://sashiko.dev/#/patchset/[email protected]
Suggested-by: Vadim Fedorenko <[email protected]>
Cc: [email protected]
Signed-off-by: Jiangshan Yi <[email protected]>

---
Changes in v2:
- Remove the defensive NULL guard in bnx2x_free_mem_bp() as suggested
  by Vadim Fedorenko, since the assignment-order fix alone is sufficient
  to prevent the NULL pointer dereference (bp is zero-initialized so
  fp_array_size remains 0 when allocation fails).

 drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
index 5b2640bd31c3..926ffe3e2c43 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
@@ -4742,13 +4742,13 @@ int bnx2x_alloc_mem_bp(struct bnx2x *bp)
 
 	/* fp array: RSS plus CNIC related L2 queues */
 	fp_array_size = BNX2X_MAX_RSS_COUNT(bp) + CNIC_SUPPORT(bp);
-	bp->fp_array_size = fp_array_size;
-	BNX2X_DEV_INFO("fp_array_size %d\n", bp->fp_array_size);
+	BNX2X_DEV_INFO("fp_array_size %d\n", fp_array_size);
 
-	fp = kzalloc_objs(*fp, bp->fp_array_size);
+	fp = kzalloc_objs(*fp, fp_array_size);
 	if (!fp)
 		goto alloc_err;
 	bp->fp = fp;
+	bp->fp_array_size = fp_array_size;
 	for (i = 0; i < bp->fp_array_size; i++) {
 		fp[i].tpa_info =
 			kzalloc_objs(struct bnx2x_agg_info,
-- 
2.25.1
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