Re: [PATCH 06/17] x86, mpx: trace attempts to find bounds tables

Dave Hansen
2015-03-27T14:08:09Z

On 03/27/2015 05:32 AM, Borislav Petkov wrote:
>> > This event traces any time we go looking to unmap a bounds table
>> > for a given virtual address range. This is useful to ensure
>> > that the kernel actually "tried" to free a bounds table versus
>> > times it succeeded.
>> >
>> > It might try and fail if it realized that a table was shared
>> > with an adjacent VMA which is not being unmapped.
> Would it make sense to extend this tracepoint to also dump the error
> values returned from unmap_edge_bts() and unmap_single_bt() inside
> mpx_unmap_tables()?

Both of the paths below this point (the "real" unmap and the zap) also
have tracepoints. It might also get confusing to see -ENOENT in the
success case. Also, in practice, you can see the siginfo get generated
and tell that something bad happened.

I think I'd rather leave it as-is.