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From: Meelis Roos <mroos@linux.ee>
To: Nilay Vaish <nilayvaish@gmail.com>
Cc: Linux Kernel list <linux-kernel@vger.kernel.org>, x86@kernel.org
Subject: Re: UBSAN: Undefined behaviour in arch/x86/events/intel/p6.c:115:29
Date: Thu, 19 May 2016 10:36:09 +0300 (EEST)	[thread overview]
Message-ID: <alpine.LRH.2.20.1605191035340.28238@math.ut.ee> (raw)
In-Reply-To: <CACbG3084SVkW4r+-RqkbZR=BUH2_fK0bnDqKNXQoRffSJtpTYQ@mail.gmail.com>

> I think UBSAN has correctly identified a bug.  I looked at the code in
> v4.6.  In file arch/x86/events/core.c, in the function
> filter_events(), there is a loop starting at line 1554 that should go
> over 10 event counters.  But in file arch/x86/events/intel/p6.c, only
> 8 event counters have been declared at line 9.
> 
> I have a fix but do not for sure if its reasonable.  I think we should
> pass on the max_events for the pmu to filter_events() function and
> change the loop condition accordingly.  Can you apply the patch below
> and test again?  It compiles, but I have not tested it.

Seems to work - warning is gone, everythins is detected as before.

-- 
Meelis Roos (mroos@linux.ee)

      reply	other threads:[~2016-05-19  7:36 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-16 18:41 Meelis Roos
2016-05-18 18:08 ` Nilay Vaish
2016-05-19  7:36   ` Meelis Roos [this message]

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