Re: [RFC PATCH v2] compat: poll() in 32-bit applications does nothandle negative timeout values properly on 64-bit kernels

From: Josh Hunt
Date: Thu Feb 16 2012 - 11:22:10 EST


On 02/11/2012 09:47 AM, Eric Dumazet wrote:
> Le vendredi 10 fÃvrier 2012 Ã 23:54 -0600, Josh Hunt a Ãcrit :
>> We have hit an issue where our 32-bit applications using poll() and
>> passing in a value of -1 for the timeout value return after ~49 days
>> (2^32 msec), instead of waiting indefinitely. I've instrumented the
>> kernel and found we are hitting the case where poll() believes we've
>> passed in a positive number and thus creates a timespec, etc. I've
>> implemented compat_sys_poll() to sign-extend the timeout value and
>> resolve the issue.
>>
>> There was an almost identical patch submitted last year, but for
>> whatever reason did not make it in:
>> https://lkml.org/lkml/2011/9/18/19
>
> Probably because Thomas Meyer didnt answer to patch reviewers, and not
> enough people cared.
>
> By the way, an inline patch is better, as stated in
> Documentation/SubmittingPatches
>
> Anyway, its time to fix this bug...
>
> Acked-by: Eric Dumazet <eric.dumazet@xxxxxxxxx>
>

I can resubmit the patch inline if you feel that will get more attention
by whoever needs to do the final approval on this.

Josh


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