* [PATCH] net/mlx4: suppress 'may be used uninitialized' warning
@ 2017-04-18 6:21 Greg Thelen
2017-04-18 7:02 ` Leon Romanovsky
2017-04-20 17:19 ` David Miller
0 siblings, 2 replies; 4+ messages in thread
From: Greg Thelen @ 2017-04-18 6:21 UTC (permalink / raw)
To: Or Gerlitz, Jack Morgenstein, Matan Barak
Cc: Ido Shamay, Yishai Hadas, Amir Vadai, Roland Dreier,
David S. Miller, netdev, linux-rdma, linux-kernel, Greg Thelen
gcc 4.8.4 complains that mlx4_SW2HW_MPT_wrapper() uses an uninitialized
'mpt' variable:
drivers/net/ethernet/mellanox/mlx4/resource_tracker.c: In function 'mlx4_SW2HW_MPT_wrapper':
drivers/net/ethernet/mellanox/mlx4/resource_tracker.c:2802:12: warning: 'mpt' may be used uninitialized in this function [-Wmaybe-uninitialized]
mpt->mtt = mtt;
I think this warning is a false complaint. mpt is only used when
mr_res_start_move_to() return zero, and in all such cases it initializes
mpt. But apparently gcc cannot see that.
Initialize mpt to avoid the warning.
Signed-off-by: Greg Thelen <gthelen@google.com>
---
drivers/net/ethernet/mellanox/mlx4/resource_tracker.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c b/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c
index d8d5d161b8c7..4aa29ee93013 100644
--- a/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c
+++ b/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c
@@ -2749,7 +2749,7 @@ int mlx4_SW2HW_MPT_wrapper(struct mlx4_dev *dev, int slave,
int err;
int index = vhcr->in_modifier;
struct res_mtt *mtt;
- struct res_mpt *mpt;
+ struct res_mpt *mpt = NULL;
int mtt_base = mr_get_mtt_addr(inbox->buf) / dev->caps.mtt_entry_sz;
int phys;
int id;
--
2.12.2.762.g0e3151a226-goog
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] net/mlx4: suppress 'may be used uninitialized' warning
2017-04-18 6:21 [PATCH] net/mlx4: suppress 'may be used uninitialized' warning Greg Thelen
@ 2017-04-18 7:02 ` Leon Romanovsky
2017-04-18 7:24 ` Greg Thelen
2017-04-20 17:19 ` David Miller
1 sibling, 1 reply; 4+ messages in thread
From: Leon Romanovsky @ 2017-04-18 7:02 UTC (permalink / raw)
To: Greg Thelen
Cc: Or Gerlitz, Jack Morgenstein, Matan Barak, Ido Shamay,
Yishai Hadas, Amir Vadai, Roland Dreier, David S. Miller, netdev,
linux-rdma, linux-kernel, Tariq Toukan
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On Mon, Apr 17, 2017 at 11:21:35PM -0700, Greg Thelen wrote:
> gcc 4.8.4 complains that mlx4_SW2HW_MPT_wrapper() uses an uninitialized
> 'mpt' variable:
> drivers/net/ethernet/mellanox/mlx4/resource_tracker.c: In function 'mlx4_SW2HW_MPT_wrapper':
> drivers/net/ethernet/mellanox/mlx4/resource_tracker.c:2802:12: warning: 'mpt' may be used uninitialized in this function [-Wmaybe-uninitialized]
> mpt->mtt = mtt;
>
> I think this warning is a false complaint. mpt is only used when
> mr_res_start_move_to() return zero, and in all such cases it initializes
> mpt.
> But apparently gcc cannot see that.
>
> Initialize mpt to avoid the warning.
>
> Signed-off-by: Greg Thelen <gthelen@google.com>
> ---
It looks like other callers of mr_res_start_move_to() have the same
"uninitialized" variable.
Thanks
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] net/mlx4: suppress 'may be used uninitialized' warning
2017-04-18 7:02 ` Leon Romanovsky
@ 2017-04-18 7:24 ` Greg Thelen
0 siblings, 0 replies; 4+ messages in thread
From: Greg Thelen @ 2017-04-18 7:24 UTC (permalink / raw)
To: Leon Romanovsky
Cc: Or Gerlitz, Jack Morgenstein, Matan Barak, Ido Shamay,
Yishai Hadas, Amir Vadai, Roland Dreier, David S. Miller, netdev,
linux-rdma, linux-kernel, Tariq Toukan
Leon Romanovsky <leon@kernel.org> wrote:
> [ Unknown signature status ]
> On Mon, Apr 17, 2017 at 11:21:35PM -0700, Greg Thelen wrote:
>> gcc 4.8.4 complains that mlx4_SW2HW_MPT_wrapper() uses an uninitialized
>> 'mpt' variable:
>> drivers/net/ethernet/mellanox/mlx4/resource_tracker.c: In function 'mlx4_SW2HW_MPT_wrapper':
>> drivers/net/ethernet/mellanox/mlx4/resource_tracker.c:2802:12: warning: 'mpt' may be used uninitialized in this function [-Wmaybe-uninitialized]
>> mpt->mtt = mtt;
>>
>> I think this warning is a false complaint. mpt is only used when
>> mr_res_start_move_to() return zero, and in all such cases it initializes
>> mpt.
>> But apparently gcc cannot see that.
>>
>> Initialize mpt to avoid the warning.
>>
>> Signed-off-by: Greg Thelen <gthelen@google.com>
>> ---
>
> It looks like other callers of mr_res_start_move_to() have the same
> "uninitialized" variable.
>
> Thanks
The above is the only mellanox warning I see. So gcc is able to better
analyze the other callsites.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] net/mlx4: suppress 'may be used uninitialized' warning
2017-04-18 6:21 [PATCH] net/mlx4: suppress 'may be used uninitialized' warning Greg Thelen
2017-04-18 7:02 ` Leon Romanovsky
@ 2017-04-20 17:19 ` David Miller
1 sibling, 0 replies; 4+ messages in thread
From: David Miller @ 2017-04-20 17:19 UTC (permalink / raw)
To: gthelen
Cc: ogerlitz, jackm, matanb, idos, yishaih, amirv, roland, netdev,
linux-rdma, linux-kernel
From: Greg Thelen <gthelen@google.com>
Date: Mon, 17 Apr 2017 23:21:35 -0700
> gcc 4.8.4 complains that mlx4_SW2HW_MPT_wrapper() uses an uninitialized
> 'mpt' variable:
> drivers/net/ethernet/mellanox/mlx4/resource_tracker.c: In function 'mlx4_SW2HW_MPT_wrapper':
> drivers/net/ethernet/mellanox/mlx4/resource_tracker.c:2802:12: warning: 'mpt' may be used uninitialized in this function [-Wmaybe-uninitialized]
> mpt->mtt = mtt;
>
> I think this warning is a false complaint. mpt is only used when
> mr_res_start_move_to() return zero, and in all such cases it initializes
> mpt. But apparently gcc cannot see that.
>
> Initialize mpt to avoid the warning.
>
> Signed-off-by: Greg Thelen <gthelen@google.com>
Appied to net-next.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2017-04-18 6:21 [PATCH] net/mlx4: suppress 'may be used uninitialized' warning Greg Thelen
2017-04-18 7:02 ` Leon Romanovsky
2017-04-18 7:24 ` Greg Thelen
2017-04-20 17:19 ` David Miller
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