[PATCH net] octeontx2-pf: avoid double free of pool->stack on AQ init failure

[PATCH net] octeontx2-pf: avoid double free of pool->stack on AQ init failure

[Dawei Feng]

otx2_pool_aq_init() frees pool->stack when mailbox sync or retry
allocation fails, but leaves the pointer unchanged. Later,
otx2_sq_aura_pool_init() unwinds the partial setup through
otx2_aura_pool_free(), which frees pool->stack again. The CN20K-specific
cn20k_pool_aq_init() implementation has the same bug in
its corresponding error path.

Set pool->stack to NULL immediately after the local free so the shared
cleanup path does not free the same stack again while cleaning up
partially initialized pool state.

The bug was first flagged by an experimental analysis tool we are
developing for kernel memory-management bugs while analyzing
v6.13-rc1. The tool is still under development and is not yet publicly
available. Manual inspection confirms that the bug is still present in
v7.1-rc3.

Runtime validation was not performed because reproducing this path
requires OcteonTX2/CN20K hardware.

Fixes: caa2da34fd25 ("octeontx2-pf: Initialize and config queues")
Fixes: d322fbd17203 ("octeontx2-pf: Initialize cn20k specific aura and pool contexts")
Cc: stable@vger.kernel.org
Signed-off-by: Zilin Guan <zilin@seu.edu.cn>
Signed-off-by: Dawei Feng <dawei.feng@seu.edu.cn>
---
 drivers/net/ethernet/marvell/octeontx2/nic/cn20k.c       | 2 ++
 drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/cn20k.c b/drivers/net/ethernet/marvell/octeontx2/nic/cn20k.c
index a5a8f4558717..dbf173196608 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/cn20k.c
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/cn20k.c
@@ -619,11 +619,13 @@ static int cn20k_pool_aq_init(struct otx2_nic *pfvf, u16 pool_id,
 		err = otx2_sync_mbox_msg(&pfvf->mbox);
 		if (err) {
 			qmem_free(pfvf->dev, pool->stack);
+			pool->stack = NULL;
 			return err;
 		}
 		aq = otx2_mbox_alloc_msg_npa_cn20k_aq_enq(&pfvf->mbox);
 		if (!aq) {
 			qmem_free(pfvf->dev, pool->stack);
+			pool->stack = NULL;
 			return -ENOMEM;
 		}
 	}
diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
index 971fcab1c248..3d253132a17f 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
@@ -1482,11 +1482,13 @@ int otx2_pool_aq_init(struct otx2_nic *pfvf, u16 pool_id,
 		err = otx2_sync_mbox_msg(&pfvf->mbox);
 		if (err) {
 			qmem_free(pfvf->dev, pool->stack);
+			pool->stack = NULL;
 			return err;
 		}
 		aq = otx2_mbox_alloc_msg_npa_aq_enq(&pfvf->mbox);
 		if (!aq) {
 			qmem_free(pfvf->dev, pool->stack);
+			pool->stack = NULL;
 			return -ENOMEM;
 		}
 	}
-- 
2.34.1