Re: Config Loop

[Alex Elder <elder@inktank.com>]

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On 01/03/2013 10:52 AM, Neil Horman wrote:
> On Thu, Jan 03, 2013 at 09:57:13AM -0600, Alex Elder wrote:
>> A commit added in the 3.8-rc1 merge window has resulted in
>> my kernel config entering an infinite loop handling the
>> "Default SCTP cookie HMAC encoding" option.
>>
>>     commit 0d0863b02002c25140a1b9e113b81211bcc780e8
>>     sctp: Change defaults on cookie hmac selection
>>
>>     http://marc.info/?l=linux-netdev&m=135553459303505
>>
>> The problem lies in my config file containing this line:
>>
>>     CONFIG_SCTP_HMAC_MD5=y
>>
>> I normally configure my kernel using fixed config file
>> (occasionally updated) using (roughly) this:
>>
>>     yes "" | make oldconfig
>>
>> The result looks like this:
>>
>> . . .
>>   DCCP connection probing (NET_DCCPPROBE) [M/n/?] m
>> *
>> * The SCTP Protocol (EXPERIMENTAL)
>> *
>> The SCTP Protocol (EXPERIMENTAL) (IP_SCTP) [M/y/?] m
>>   SCTP: Association probing (NET_SCTPPROBE) [M/n/?] m
>>   SCTP: Debug messages (SCTP_DBG_MSG) [N/y/?] n
>>   SCTP: Debug object counts (SCTP_DBG_OBJCNT) [N/y/?] n
>>   Default SCTP cookie HMAC encoding
>>     1. Enable optional MD5 hmac cookie generation
>> (SCTP_DEFAULT_COOKIE_HMAC_MD5) (NEW)
>>     2. Enable optional SHA1 hmac cookie generation
>> (SCTP_DEFAULT_COOKIE_HMAC_SHA1) (NEW)
>>     3. Use no hmac alg in SCTP cookie generation
>> (SCTP_DEFAULT_COOKIE_HMAC_NONE) (NEW)
>>   choice[1-3?]:   Default SCTP cookie HMAC encoding
>>     1. Enable optional MD5 hmac cookie generation
>> (SCTP_DEFAULT_COOKIE_HMAC_MD5) (NEW)
>>     2. Enable optional SHA1 hmac cookie generation
>> (SCTP_DEFAULT_COOKIE_HMAC_SHA1) (NEW)
>>     3. Use no hmac alg in SCTP cookie generation
>> (SCTP_DEFAULT_COOKIE_HMAC_NONE) (NEW)
>>   choice[1-3?]:   Default SCTP cookie HMAC encoding
>> . . .  and so on.
>>
>> I find that I can correct this with the patch below.
>> I expect others will bump into the same problem.  In
>> particular, I notice my Ubuntu config files contain
>> that same line.
>>
>> I don't know how best to handle this, but I thought
>> I would report it in case someone has a good solution.
>>
> Thats odd.  It looks like your selection of a defaut value for the sctp cookie
> hmac algorithm isn't taking at all.  I just added the old CONFIG_SCTP_HMAC_MD5=y
> option to my config and used your:
> yes "" | make oldconfig 
> setup, and it worked fine for me.  And you say if you remove the old config
> option first, you get no loop?

I say that when I apply the patch (below) there is no loop.

I noticed the loop with v3.8-rc1 and it's still happening
with v3.8-rc2.  I've attached the working config I'm now
using to this message.  The only difference between the
looping one and the working one is that this:
    CONFIG_SCTP_HMAC_MD5=y
has been replaced with this:
    CONFIG_SCTP_DEFAULT_COOKIE_HMAC_MD5=y

					-Alex
]
> Neil
> 
>> 					-Alex
>>
>>  arch/x86/configs/autobuild |    2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> Index: b/arch/x86/configs/autobuild
>> ===================================================================
>> --- a/arch/x86/configs/autobuild
>> +++ b/arch/x86/configs/autobuild
>> @@ -940,7 +940,7 @@ CONFIG_NET_SCTPPROBE=m
>>  # CONFIG_SCTP_DBG_OBJCNT is not set
>>  # CONFIG_SCTP_HMAC_NONE is not set
>>  # CONFIG_SCTP_HMAC_SHA1 is not set
>> -CONFIG_SCTP_HMAC_MD5=y
>> +CONFIG_SCTP_DEFAULT_COOKIE_HMAC_MD5=y
>>  CONFIG_RDS=m
>>  CONFIG_RDS_RDMA=m
>>  CONFIG_RDS_TCP=m
>> --
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>>


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