This is a note to let you know that I've just added the patch titled
i40e: fix endless loop under rtnl
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
i40e-fix-endless-loop-under-rtnl.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 515e551c3e109d340e173ff2e4e3e3db8fac7994
Author: Jiri Benc <jbenc@xxxxxxxxxx>
Date: Tue Sep 14 10:54:42 2021 +0200
i40e: fix endless loop under rtnl
[ Upstream commit 857b6c6f665cca9828396d9743faf37fd09e9ac3 ]
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 <sassmann@xxxxxxxxxx>
Signed-off-by: Jiri Benc <jbenc@xxxxxxxxxx>
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@xxxxxxxxx>
Tested-by: Dave Switzer <david.switzer@xxxxxxxxx>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
index d6d4faa5c542..2137c4e7289e 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -6574,7 +6574,7 @@ 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),
