From: Netanel Belgazal <netanel@annapurnalabs.com>
To: Matt Wilson <msw@amzn.com>
Cc: linux-kernel@vger.kernel.org, davem@davemloft.net,
netdev@vger.kernel.org, dwmw@amazon.com, zorik@annapurnalabs.com,
alex@annapurnalabs.com, saeed@annapurnalabs.com, msw@amazon.com,
aliguori@amazon.com, nafea@annapurnalabs.com
Subject: Re: [PATCH V2 net 06/20] net/ena: fix NULL dereference when removing the driver after device reset faild
Date: Mon, 5 Dec 2016 20:30:44 +0200 [thread overview]
Message-ID: <1d2c91e8-4bbe-5cbf-7d35-d682e5de6aa5@annapurnalabs.com> (raw)
In-Reply-To: <20161205042915.GH4310@u54ee753d2d1854bda401.ant.amazon.com>
On 12/05/2016 06:29 AM, Matt Wilson wrote:
> On Sun, Dec 04, 2016 at 03:19:24PM +0200, Netanel Belgazal wrote:
>> If for some reason the device stop responding and the device reset failed
>> to recover the device, the mmio register read datastructure will not be
>> reinitialized.
> If for some reason the device stops responding, and the device reset
> fails to recover the device, the MMIO register read data structure
> will not be reinitialized.
OK
>
>> On driver removal, the driver will also tries to reset the device
>> but this time the mmio data structure will be NULL.
> On driver removal, the driver will also try to reset the device, but
> this time the MMIO data structure will be NULL.
OK
>> To solve this issue perform the device reset in the remove function only if
>> the device is runnig.
> To solve this issue, perform the device reset in the remove function
> only if the device is running.
>
> Do you have an example of the NULL pointer dereference that you can
> paste in? It can be helpful for those searching for a fix for a bug
> they've experienced.
I'll add a crash dump.
> --msw
>
>> Signed-off-by: Netanel Belgazal <netanel@annapurnalabs.com>
>> ---
>> drivers/net/ethernet/amazon/ena/ena_netdev.c | 6 +++++-
>> 1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c b/drivers/net/ethernet/amazon/ena/ena_netdev.c
>> index 224302c..ad5f78f 100644
>> --- a/drivers/net/ethernet/amazon/ena/ena_netdev.c
>> +++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c
>> @@ -2516,6 +2516,8 @@ static void ena_fw_reset_device(struct work_struct *work)
>> err:
>> rtnl_unlock();
>>
>> + clear_bit(ENA_FLAG_DEVICE_RUNNING, &adapter->flags);
>> +
>> dev_err(&pdev->dev,
>> "Reset attempt failed. Can not reset the device\n");
>> }
>> @@ -3126,7 +3128,9 @@ static void ena_remove(struct pci_dev *pdev)
>>
>> cancel_work_sync(&adapter->resume_io_task);
>>
>> - ena_com_dev_reset(ena_dev);
>> + /* Reset the device only if the device is running. */
>> + if (test_bit(ENA_FLAG_DEVICE_RUNNING, &adapter->flags))
>> + ena_com_dev_reset(ena_dev);
>>
>> ena_free_mgmnt_irq(adapter);
>>
next prev parent reply other threads:[~2016-12-05 18:30 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-04 13:19 [PATCH V2 net 00/20] Increase ENA driver version to 1.1.2 Netanel Belgazal
2016-12-04 13:19 ` [PATCH V2 net 01/20] net/ena: remove ntuple filter support from device feature list Netanel Belgazal
2016-12-05 4:08 ` Matt Wilson
2016-12-04 13:19 ` [PATCH V2 net 02/20] net/ena: fix error handling when probe fails Netanel Belgazal
2016-12-05 4:09 ` Matt Wilson
2016-12-05 18:23 ` Netanel Belgazal
2016-12-04 13:19 ` [PATCH V2 net 03/20] net/ena: fix queues number calculation Netanel Belgazal
2016-12-05 4:11 ` Matt Wilson
2016-12-05 18:25 ` Netanel Belgazal
2016-12-04 13:19 ` [PATCH V2 net 04/20] net/ena: fix ethtool RSS flow configuration Netanel Belgazal
2016-12-05 4:18 ` Matt Wilson
2016-12-05 18:26 ` Netanel Belgazal
2016-12-04 13:19 ` [PATCH V2 net 05/20] net/ena: fix RSS default hash configuration Netanel Belgazal
2016-12-05 4:20 ` Matt Wilson
2016-12-05 18:32 ` Netanel Belgazal
2016-12-04 13:19 ` [PATCH V2 net 06/20] net/ena: fix NULL dereference when removing the driver after device reset faild Netanel Belgazal
2016-12-05 4:29 ` Matt Wilson
2016-12-05 18:30 ` Netanel Belgazal [this message]
2016-12-04 13:19 ` [PATCH V2 net 07/20] net/ena: refactor ena_get_stats64 to be atomic context safe Netanel Belgazal
2016-12-05 4:24 ` Matt Wilson
2016-12-05 18:29 ` Netanel Belgazal
2016-12-04 13:19 ` [PATCH V2 net 08/20] net/ena: add hardware hints capability to the driver Netanel Belgazal
2016-12-05 4:31 ` Matt Wilson
2016-12-05 18:31 ` Netanel Belgazal
2016-12-04 13:19 ` [PATCH V2 net 09/20] net/ena: fix potential access to freed memory during device reset Netanel Belgazal
2016-12-04 13:19 ` [PATCH V2 net 10/20] net/ena: remove redundant logic in napi callback for busy poll mode Netanel Belgazal
2016-12-05 5:45 ` Eric Dumazet
2016-12-05 18:29 ` Netanel Belgazal
2016-12-05 18:51 ` Eric Dumazet
2016-12-04 13:19 ` [PATCH V2 net 11/20] net/ena: use READ_ONCE to access completion descriptors Netanel Belgazal
2016-12-04 13:19 ` [PATCH V2 net 12/20] net/ena: reduce the severity of ena printouts Netanel Belgazal
2016-12-04 13:19 ` [PATCH V2 net 13/20] net/ena: change driver's default timeouts Netanel Belgazal
2016-12-05 4:35 ` Matt Wilson
2016-12-05 18:28 ` Netanel Belgazal
2016-12-04 13:19 ` [PATCH V2 net 14/20] net/ena: change condition for host attribute configuration Netanel Belgazal
2016-12-04 13:19 ` [PATCH V2 net 15/20] net/ena: change sizeof() argument to be the type pointer Netanel Belgazal
2016-12-04 13:19 ` [PATCH V2 net 16/20] net/ena: use napi_schedule_irqoff when possible Netanel Belgazal
2016-12-04 13:19 ` [PATCH V2 net 17/20] net/ena: add IPv6 extended protocols to ena_admin_flow_hash_proto Netanel Belgazal
2016-12-04 13:19 ` [PATCH V2 net 18/20] net/ena: remove affinity hint from the driver Netanel Belgazal
2016-12-04 13:19 ` [PATCH V2 net 19/20] net/ena: restructure skb allocation Netanel Belgazal
2016-12-04 13:19 ` [PATCH V2 net 20/20] net/ena: increase driver version to 1.1.2 Netanel Belgazal
2016-12-05 2:37 ` [PATCH V2 net 00/20] Increase ENA " David Miller
2016-12-05 3:30 ` Matt Wilson
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