From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jesse Brandeburg Date: Tue, 14 Sep 2021 16:37:55 -0700 Subject: [Intel-wired-lan] [PATCH net] i40e: fix endless loop under rtnl In-Reply-To: <4d94f7fbd9dd6476c5adc8967f3db84bc9204f47.1630319620.git.jbenc@redhat.com> References: <4d94f7fbd9dd6476c5adc8967f3db84bc9204f47.1630319620.git.jbenc@redhat.com> Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: intel-wired-lan@osuosl.org List-ID: +intel-wired-lan list On 8/30/2021 3:34 AM, Jiri Benc wrote: > 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 > enocunter the same problem on its next invocation. As the result, the loop encounter > 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). If the firmware doesn't reply we have a lot of problems. > 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. That's really frustrating, sorry! We are actively working to do better by working with you more closely. This one must have slipped through the cracks. > This may not be the best possible fix but it's better than hanging the whole > system on a firmware bug. > The fix seems fine to me on initial review. you can add my Reviewed-by: Jesse Brandeburg but... Missing Fixes: tag? > Tested-by: Stefan Assmann > Signed-off-by: Jiri Benc > --- > drivers/net/ethernet/intel/i40e/i40e_main.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c > index 1d1f52756a93..772dd05a0ae8 100644 > --- a/drivers/net/ethernet/intel/i40e/i40e_main.c > +++ b/drivers/net/ethernet/intel/i40e/i40e_main.c > @@ -10110,7 +10110,7 @@ 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), >