Re: [PATCH] kernel/trace/trace_functions_graph.c: fix nsecs_str buffer size

[Daniel Mack <daniel@caiaq.de>]

Hi Frederic,

On Mon, Mar 23, 2009 at 05:40:31PM +0100, Frederic Weisbecker wrote:
> It can't really happen because nsecs_rem is a rest of a division
> per 1000, so it will not exceed 3 digits (so it should be [4] and not
> [5], btw).
> 
> I must confess I should have added a better comment on this
> area.
> 
> We are printing a duration in usec with a part in nsec with the following
> constraints:
> 
> _ never exceed 7 characters unless we are are upper 9999999 usecs
> _ always keep the usecs consistants
> 
> Which means that while we have 4 or lesser digits for the usecs, we can
> print the 3 digits of the nanosecs.
> 
> If we need 5 for usecs, drop the least significant nanosec digit.
> If we need 6 for usecs, drop the two least significant nanosec digits

Ok, I see. I was just confused about the max len argument to snprintf()
(and so was cppcheck), but at a closer look, this can't become a
problem.

Nevermind, drop the patch - but good that we talked about it :)

Daniel