Re: [PATCH] net/mlx4: suppress 'may be used uninitialized' warning

From	Greg Thelen <gthelen@google.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH] net/mlx4: suppress 'may be used uninitialized' warning
Date	2017-04-18 09:30 +0200
Message-ID	<txvKi-3lc-7@gated-at.bofh.it> (permalink)
References	<txuOd-2MU-5@gated-at.bofh.it> <txvqW-3eI-9@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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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.

Thread

[PATCH] net/mlx4: suppress 'may be used uninitialized' warning Greg Thelen <gthelen@google.com> - 2017-04-18 08:30 +0200
  Re: [PATCH] net/mlx4: suppress 'may be used uninitialized' warning Leon Romanovsky <leon@kernel.org> - 2017-04-18 09:10 +0200
    Re: [PATCH] net/mlx4: suppress 'may be used uninitialized' warning Greg Thelen <gthelen@google.com> - 2017-04-18 09:30 +0200
  Re: [PATCH] net/mlx4: suppress 'may be used uninitialized' warning David Miller <davem@davemloft.net> - 2017-04-20 19:30 +0200

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