Re: [PATCH 1/1] block: Range check cpu in blk_cpu_to_group

[Jens Axboe]

On 09/09/2010 07:41 PM, Brian King wrote:
> While testing CPU DLPAR, the following problem was discovered.
> We were DLPAR removing the first CPU, which in this case was
> logical CPUs 0-3. CPUs 0-2 were already marked offline and
> we were in the process of offlining CPU 3. After marking
> the CPU inactive and offline in cpu_disable, but before the
> cpu was completely idle (cpu_die), we ended up in __make_request
> on CPU 3. There we looked at the topology map to see which CPU
> to complete the I/O on and found no CPUs in the cpu_sibling_map.
> This resulted in the block layer setting the completion cpu
> to be NR_CPUS, which then caused an oops when we tried to
> complete the I/O.
> 
> Fix this by sanity checking the value we return from blk_cpu_to_group
> to be a valid cpu value.
> 
> Signed-off-by: Brian King <brking@xxxxxxxxxxxxxxxxxx>

Thanks Brian, applied.

-- 
Jens Axboe

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