[PATCH net 3/6] pds_core: handle unsupported PDS_CORE_CMD_FW_CONTROL result

[Shannon Nelson]

From: Brett Creeley <brett.creeley@xxxxxxx>

If the FW doesn't support the PDS_CORE_CMD_FW_CONTROL command
the driver might at the least print garbage and at the worst
crash when the user runs the "devlink dev info" devlink command.

This happens because the stack variable fw_list is not 0
initialized which results in fw_list.num_fw_slots being a
garbage value from the stack.  Then the driver tries to access
fw_list.fw_names[i] with i >= ARRAY_SIZE and runs off the end
of the array.

Fix this by initializing the fw_list and adding an ARRAY_SIZE
limiter to the loop, and by not failing completely if the
devcmd fails because other useful information is printed via
devlink dev info even if the devcmd fails.

Fixes: 45d76f492938 ("pds_core: set up device and adminq")
Signed-off-by: Brett Creeley <brett.creeley@xxxxxxx>
Signed-off-by: Shannon Nelson <shannon.nelson@xxxxxxx>
---
 drivers/net/ethernet/amd/pds_core/devlink.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/amd/pds_core/devlink.c b/drivers/net/ethernet/amd/pds_core/devlink.c
index c5c787df61a4..d8dc39da4161 100644
--- a/drivers/net/ethernet/amd/pds_core/devlink.c
+++ b/drivers/net/ethernet/amd/pds_core/devlink.c
@@ -105,7 +105,7 @@ int pdsc_dl_info_get(struct devlink *dl, struct devlink_info_req *req,
 		.fw_control.opcode = PDS_CORE_CMD_FW_CONTROL,
 		.fw_control.oper = PDS_CORE_FW_GET_LIST,
 	};
-	struct pds_core_fw_list_info fw_list;
+	struct pds_core_fw_list_info fw_list = {};
 	struct pdsc *pdsc = devlink_priv(dl);
 	union pds_core_dev_comp comp;
 	char buf[32];
@@ -118,8 +118,6 @@ int pdsc_dl_info_get(struct devlink *dl, struct devlink_info_req *req,
 	if (!err)
 		memcpy_fromio(&fw_list, pdsc->cmd_regs->data, sizeof(fw_list));
 	mutex_unlock(&pdsc->devcmd_lock);
-	if (err && err != -EIO)
-		return err;
 
 	listlen = min(fw_list.num_fw_slots, ARRAY_SIZE(fw_list.fw_names));
 	for (i = 0; i < listlen; i++) {
-- 
2.17.1