[PATCH 6.1.y 1/2] scsi: qla2xxx: Fix queue teardown NULL dma_free and bitmap locking

[Sasha Levin <sashal@kernel.org>]

From: Nilesh Javali <njavali@marvell.com>

[ Upstream commit 34a40e0dff940ac5eba494a69b553ea571e24873 ]

qla25xx_free_req_que() and qla25xx_free_rsp_que() have two pre-existing
bugs exposed on the error path of qla25xx_create_{req,rsp}_que():

 1. When dma_alloc_coherent() fails during queue creation, the error
    path calls the free function with req->ring / rsp->ring still NULL
    (from kzalloc).  The unconditional dma_free_coherent() with a NULL
    cpu_addr is undefined behavior and can panic.

 2. The free functions clear req_qid_map / rsp_qid_map under vport_lock,
    but the create functions protect the same bitmaps with mq_lock.
    This provides no mutual exclusion.  Additionally, the create error
    path clears the bit and releases mq_lock before calling the free
    function, creating a window where another thread can allocate the
    same que_id and have its ha->req_q_map entry clobbered by the
    subsequent lockless NULL assignment in the free function.

Fix by:

 - Guarding dma_free_coherent() with a NULL check on the ring pointer.

 - Using mq_lock (the lock held by all creators) in the free functions
   to atomically NULL the map entry and clear the bitmap bit.

 - Removing the now-redundant clear_bit blocks from the create error
   paths since the free functions handle it atomically.

Signed-off-by: Nilesh Javali <njavali@marvell.com>
Reviewed-by: Hannes Reinecke <hare@kernel.org>
Link: https://patch.msgid.link/20260723050413.3897522-41-njavali@marvell.com
Signed-off-by: Martin K. Petersen (Oracle) <mkp@kernel.org>

Backport adaptation for the stable tree: the 29xx IOCB size-selection
helpers are absent, and queue creation still allocates fixed-size entries.
Initialize the local req_entry_size and rsp_entry_size values with
sizeof(request_t) and sizeof(response_t), respectively, so DMA freeing
continues to match allocation without adding helper functions or 29xx
support. Retain all NULL-ring guards, mq_lock protection, and removal of
the premature bitmap clears.

Keep the response-ring cleanup layout used by upstream so target commit
19788a55cab61d78e33e0914a5a31d27843e8a4a applies unchanged.

Stable-dep-of: 19788a55cab6 ("scsi: qla2xxx: Fix use-after-free of qpair work on queue teardown")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/scsi/qla2xxx/qla_mid.c | 29 +++++++++++++++--------------
 1 file changed, 15 insertions(+), 14 deletions(-)

diff --git a/drivers/scsi/qla2xxx/qla_mid.c b/drivers/scsi/qla2xxx/qla_mid.c
index 79e4319bbbd28..b25439db6867d 100644
--- a/drivers/scsi/qla2xxx/qla_mid.c
+++ b/drivers/scsi/qla2xxx/qla_mid.c
@@ -583,16 +583,19 @@ qla25xx_free_req_que(struct scsi_qla_host *vha, struct req_que *req)
 {
 	struct qla_hw_data *ha = vha->hw;
 	uint16_t que_id = req->id;
+	size_t req_entry_size = sizeof(request_t);
 
-	dma_free_coherent(&ha->pdev->dev, (req->length + 1) *
-		sizeof(request_t), req->ring, req->dma);
+	if (req->ring)
+		dma_free_coherent(&ha->pdev->dev,
+				  (req->length + 1) * req_entry_size,
+				  req->ring, req->dma);
 	req->ring = NULL;
 	req->dma = 0;
 	if (que_id) {
+		mutex_lock(&ha->mq_lock);
 		ha->req_q_map[que_id] = NULL;
-		mutex_lock(&ha->vport_lock);
 		clear_bit(que_id, ha->req_qid_map);
-		mutex_unlock(&ha->vport_lock);
+		mutex_unlock(&ha->mq_lock);
 	}
 	kfree(req->outstanding_cmds);
 	kfree(req);
@@ -603,6 +606,7 @@ qla25xx_free_rsp_que(struct scsi_qla_host *vha, struct rsp_que *rsp)
 {
 	struct qla_hw_data *ha = vha->hw;
 	uint16_t que_id = rsp->id;
+	size_t rsp_entry_size = sizeof(response_t);
 
 	if (rsp->msix && rsp->msix->have_irq) {
 		free_irq(rsp->msix->vector, rsp->msix->handle);
@@ -610,15 +614,18 @@ qla25xx_free_rsp_que(struct scsi_qla_host *vha, struct rsp_que *rsp)
 		rsp->msix->in_use = 0;
 		rsp->msix->handle = NULL;
 	}
-	dma_free_coherent(&ha->pdev->dev, (rsp->length + 1) *
-		sizeof(response_t), rsp->ring, rsp->dma);
+
+	if (rsp->ring)
+		dma_free_coherent(&ha->pdev->dev,
+				  (rsp->length + 1) * rsp_entry_size,
+				  rsp->ring, rsp->dma);
 	rsp->ring = NULL;
 	rsp->dma = 0;
 	if (que_id) {
+		mutex_lock(&ha->mq_lock);
 		ha->rsp_q_map[que_id] = NULL;
-		mutex_lock(&ha->vport_lock);
 		clear_bit(que_id, ha->rsp_qid_map);
-		mutex_unlock(&ha->vport_lock);
+		mutex_unlock(&ha->mq_lock);
 	}
 	kfree(rsp);
 }
@@ -803,9 +810,6 @@ qla25xx_create_req_que(struct qla_hw_data *ha, uint16_t options,
 		if (ret != QLA_SUCCESS) {
 			ql_log(ql_log_fatal, base_vha, 0x00df,
 			    "%s failed.\n", __func__);
-			mutex_lock(&ha->mq_lock);
-			clear_bit(que_id, ha->req_qid_map);
-			mutex_unlock(&ha->mq_lock);
 			goto que_failed;
 		}
 		vha->flags.qpairs_req_created = 1;
@@ -917,9 +921,6 @@ qla25xx_create_rsp_que(struct qla_hw_data *ha, uint16_t options,
 		if (ret != QLA_SUCCESS) {
 			ql_log(ql_log_fatal, base_vha, 0x00e7,
 			    "%s failed.\n", __func__);
-			mutex_lock(&ha->mq_lock);
-			clear_bit(que_id, ha->rsp_qid_map);
-			mutex_unlock(&ha->mq_lock);
 			goto que_failed;
 		}
 		vha->flags.qpairs_rsp_created = 1;
-- 
2.53.0