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Date: Thu, 24 Oct 2002 21:16:33 +0530
From: Dipankar Sarma <dipankar@in.ibm.com>
To: Ed Tomlinson <tomlins@cam.org>
Cc: maneesh@in.ibm.com, linux-kernel@vger.kernel.org,
       Rusty Russell <rusty@rustcorp.com.au>, Andrew Morton <akpm@zip.com.au>
Subject: Re: [long]2.5.44-mm3 UP went into unexpected trashing
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On Thu, Oct 24, 2002 at 09:01:05PM +0530, Dipankar Sarma wrote:
> OK, I think I know why this one didn't work.
> 
> If the bit_mask is 0, find_first_bit() returns 32 or BITS_PER_LONG.
> That works fine as long as NR_CPUS is 32, but when it isn't things
> are broken.
> 
>     (find_first_bit(rcu_ctrlblk.rcu_cpu_mask, NR_CPUS) != BITS_PER_LONG)) {
> 		return;
> 
> should probably work here.
> 
> I guess we need to audit all bitmask tests and fix them to check for
> the right value. 

Argh!! I spoke too soon.

AFAICS, find_first_bit() needs to be fixed to return "size" if the
bitmask is all zeros.

Thanks
-- 
Dipankar Sarma  <dipankar@in.ibm.com> http://lse.sourceforge.net
Linux Technology Center, IBM Software Lab, Bangalore, India.
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