2021-03-04 07:17:09

by Michal Suchánek

[permalink] [raw]
Subject: [PATCH] ibmvnic: Fix possibly uninitialized old_num_tx_queues variable warning.

GCC 7.5 reports:
../drivers/net/ethernet/ibm/ibmvnic.c: In function 'ibmvnic_reset_init':
../drivers/net/ethernet/ibm/ibmvnic.c:5373:51: warning: 'old_num_tx_queues' may be used uninitialized in this function [-Wmaybe-uninitialized]
../drivers/net/ethernet/ibm/ibmvnic.c:5373:6: warning: 'old_num_rx_queues' may be used uninitialized in this function [-Wmaybe-uninitialized]

The variable is initialized only if(reset) and used only if(reset &&
something) so this is a false positive. However, there is no reason to
not initialize the variables unconditionally avoiding the warning.

Fixes: 635e442f4a48 ("ibmvnic: merge ibmvnic_reset_init and ibmvnic_init")
Signed-off-by: Michal Suchanek <[email protected]>
---
drivers/net/ethernet/ibm/ibmvnic.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index 118a4bd3f877..3bad762083c5 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -5219,16 +5219,14 @@ static int ibmvnic_reset_init(struct ibmvnic_adapter *adapter, bool reset)
{
struct device *dev = &adapter->vdev->dev;
unsigned long timeout = msecs_to_jiffies(20000);
- u64 old_num_rx_queues, old_num_tx_queues;
+ u64 old_num_rx_queues = adapter->req_rx_queues;
+ u64 old_num_tx_queues = adapter->req_tx_queues;
int rc;

adapter->from_passive_init = false;

- if (reset) {
- old_num_rx_queues = adapter->req_rx_queues;
- old_num_tx_queues = adapter->req_tx_queues;
+ if (reset)
reinit_completion(&adapter->init_done);
- }

adapter->init_done_rc = 0;
rc = ibmvnic_send_crq_init(adapter);
--
2.26.2


2021-03-04 07:19:19

by Sukadev Bhattiprolu

[permalink] [raw]
Subject: Re: [PATCH] ibmvnic: Fix possibly uninitialized old_num_tx_queues variable warning.

Michal Suchanek [[email protected]] wrote:
> GCC 7.5 reports:
> ../drivers/net/ethernet/ibm/ibmvnic.c: In function 'ibmvnic_reset_init':
> ../drivers/net/ethernet/ibm/ibmvnic.c:5373:51: warning: 'old_num_tx_queues' may be used uninitialized in this function [-Wmaybe-uninitialized]
> ../drivers/net/ethernet/ibm/ibmvnic.c:5373:6: warning: 'old_num_rx_queues' may be used uninitialized in this function [-Wmaybe-uninitialized]
>
> The variable is initialized only if(reset) and used only if(reset &&
> something) so this is a false positive. However, there is no reason to
> not initialize the variables unconditionally avoiding the warning.

Yeah, its a false positive, but initializing doesn't hurt.
>
> Fixes: 635e442f4a48 ("ibmvnic: merge ibmvnic_reset_init and ibmvnic_init")
> Signed-off-by: Michal Suchanek <[email protected]>

Reviewed-by: Sukadev Bhattiprolu <[email protected]>

2021-03-04 12:13:08

by patchwork-bot+netdevbpf

[permalink] [raw]
Subject: Re: [PATCH] ibmvnic: Fix possibly uninitialized old_num_tx_queues variable warning.

Hello:

This patch was applied to netdev/net.git (refs/heads/master):

On Tue, 2 Mar 2021 20:47:47 +0100 you wrote:
> GCC 7.5 reports:
> ../drivers/net/ethernet/ibm/ibmvnic.c: In function 'ibmvnic_reset_init':
> ../drivers/net/ethernet/ibm/ibmvnic.c:5373:51: warning: 'old_num_tx_queues' may be used uninitialized in this function [-Wmaybe-uninitialized]
> ../drivers/net/ethernet/ibm/ibmvnic.c:5373:6: warning: 'old_num_rx_queues' may be used uninitialized in this function [-Wmaybe-uninitialized]
>
> The variable is initialized only if(reset) and used only if(reset &&
> something) so this is a false positive. However, there is no reason to
> not initialize the variables unconditionally avoiding the warning.
>
> [...]

Here is the summary with links:
- ibmvnic: Fix possibly uninitialized old_num_tx_queues variable warning.
https://git.kernel.org/netdev/net/c/6881b07fdd24

You are awesome, thank you!
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