Re: [PATCH] aquantia: Fix "ethtool -S" crash when adapter down.

[Pavel Belous]

On 04.05.2017 19:51, David Miller wrote:

From: Lino Sanfilippo <linosanfili...@gmx.de>
Date: Thu, 4 May 2017 18:48:12 +0200

Hi Pavel,

On 04.05.2017 18:33, Pavel Belous wrote:

From: Pavel Belous <pavel.bel...@aquantia.com>

This patch fixes the crash that happens when driver tries to collect statistics
from already released "aq_vec" object.

Fixes: 97bde5c4f909 ("net: ethernet: aquantia: Support for NIC-specific code")
Signed-off-by: Pavel Belous <pavel.bel...@aquantia.com>
---
 drivers/net/ethernet/aquantia/atlantic/aq_nic.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/aquantia/atlantic/aq_nic.c 
b/drivers/net/ethernet/aquantia/atlantic/aq_nic.c
index cdb0299..3a32573 100644
--- a/drivers/net/ethernet/aquantia/atlantic/aq_nic.c
+++ b/drivers/net/ethernet/aquantia/atlantic/aq_nic.c
@@ -755,7 +755,7 @@ void aq_nic_get_stats(struct aq_nic_s *self, u64 *data)
        count = 0U;

        for (i = 0U, aq_vec = self->aq_vec[0];
-               self->aq_vecs > i; ++i, aq_vec = self->aq_vec[i]) {
+               aq_vec && self->aq_vecs > i; ++i, aq_vec = self->aq_vec[i]) {
                data += count;
                aq_vec_get_sw_stats(aq_vec, data, &count);
        }
@@ -961,6 +961,7 @@ void aq_nic_free_hot_resources(struct aq_nic_s *self)
        for (i = AQ_DIMOF(self->aq_vec); i--;) {
                if (self->aq_vec[i])
                        aq_vec_free(self->aq_vec[i]);
+                       self->aq_vec[i] = NULL;
        }

 err_exit:;

if the driver does not support statistics when the interface is down, would not 
it be clearer
to check if netif_running() in get_stats() instead?

Yes, much cleaner.

Much better would be to have a cached software copy so that statistics
can be reported regardless of whether the device is down or not.

Thank you.
I will think about how to do it better.

Regards,
Pavel