From 857b6c6f665cca9828396d9743faf37fd09e9ac3 Mon Sep 17 00:00:00 2001 From: Jiri Benc Date: Tue, 14 Sep 2021 10:54:42 +0200 Subject: i40e: fix endless loop under rtnl The loop in i40e_get_capabilities can never end. The problem is that although i40e_aq_discover_capabilities returns with an error if there's a firmware problem, the returned error is not checked. There is a check for pf->hw.aq.asq_last_status but that value is set to I40E_AQ_RC_OK on most firmware problems. When i40e_aq_discover_capabilities encounters a firmware problem, it will encounter the same problem on its next invocation. As the result, the loop becomes endless. We hit this with I40E_ERR_ADMIN_QUEUE_TIMEOUT but looking at the code, it can happen with a range of other firmware errors. I don't know what the correct behavior should be: whether the firmware should be retried a few times, or whether pf->hw.aq.asq_last_status should be always set to the encountered firmware error (but then it would be pointless and can be just replaced by the i40e_aq_discover_capabilities return value). However, the current behavior with an endless loop under the rtnl mutex(!) is unacceptable and Intel has not submitted a fix, although we explained the bug to them 7 months ago. This may not be the best possible fix but it's better than hanging the whole system on a firmware bug. Fixes: 56a62fc86895 ("i40e: init code and hardware support") Tested-by: Stefan Assmann Signed-off-by: Jiri Benc Reviewed-by: Jesse Brandeburg Tested-by: Dave Switzer Signed-off-by: Tony Nguyen --- drivers/net/ethernet/intel/i40e/i40e_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/net/ethernet') diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c index 2f20980dd9a5..b5b984754ec9 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_main.c +++ b/drivers/net/ethernet/intel/i40e/i40e_main.c @@ -10113,7 +10113,7 @@ static int i40e_get_capabilities(struct i40e_pf *pf, if (pf->hw.aq.asq_last_status == I40E_AQ_RC_ENOMEM) { /* retry with a larger buffer */ buf_len = data_size; - } else if (pf->hw.aq.asq_last_status != I40E_AQ_RC_OK) { + } else if (pf->hw.aq.asq_last_status != I40E_AQ_RC_OK || err) { dev_info(&pf->pdev->dev, "capability discovery failed, err %s aq_err %s\n", i40e_stat_str(&pf->hw, err), -- cgit v1.2.3-59-g8ed1b