linux-kernel - Re: [PATCH/RFC] RDMA/iwpm: Fix uninitialized error code in iwpm_send

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Date:   Wed, 29 Nov 2017 09:10:25 +0100
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Jason Gunthorpe <jgg@...pe.ca>
Cc:     Tatyana Nikolova <Tatyana.E.Nikolova@...el.com>,
        Doug Ledford <dledford@...hat.com>,
        Arnd Bergmann <arnd@...db.de>,
        linux-rdma <linux-rdma@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH/RFC] RDMA/iwpm: Fix uninitialized error code in iwpm_send_mapinfo()

Hi Jason,

On Wed, Nov 29, 2017 at 12:08 AM, Jason Gunthorpe <jgg@...pe.ca> wrote:
> On Thu, Nov 16, 2017 at 11:26:04AM +0100, Geert Uytterhoeven wrote:
>> With gcc-4.1.2:
>>
>>     drivers/infiniband/core/iwpm_util.c: In function ‘iwpm_send_mapinfo’:
>>     drivers/infiniband/core/iwpm_util.c:647: warning: ‘ret’ may be used uninitialized in this function
>>
>> Indeed, if nl_client is not found in any of the scanned has buckets, ret
>> will be used uninitialized.
>>
>> Preinitialize ret to zero to fix this.
>
> Did we come to a conclusion if we should apply this to the RMDA tree? The
> patch was marked RFC..

So far no one commented on what's the correct behavior in case of failure,
which was the actual reason for the RFC.

>> Fixes: 30dc5e63d6a5ad24 ("RDMA/core: Add support for iWARP Port Mapper user space service")
>> Signed-off-by: Geert Uytterhoeven <geert@...ux-m68k.org>
>> RFC as I have no idea if this can ever happen, and if yes, what's the
>> correct behavior to handle it:
>>   - return 0,
>>   - return an error code,
>>   - don't send anything,
>>   - anything else?
>>  drivers/infiniband/core/iwpm_util.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/infiniband/core/iwpm_util.c b/drivers/infiniband/core/iwpm_util.c
>> index 3c4faadb8cddd7fd..eb000b540495acd1 100644
>> +++ b/drivers/infiniband/core/iwpm_util.c
>> @@ -644,7 +644,7 @@ int iwpm_send_mapinfo(u8 nl_client, int iwpm_pid)
>>       int i = 0, nlmsg_bytes = 0;
>>       unsigned long flags;
>>       const char *err_str = "";
>> -     int ret;
>> +     int ret = 0;
>>
>>       skb = dev_alloc_skb(NLMSG_GOODSIZE);
>>       if (!skb) {

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds