On 09.06.09 18:47:25, John Levon wrote:
> On Tue, Jun 09, 2009 at 10:17:05PM +0200, Robert Richter wrote:
> > > Yes, this looks like a problem. buffer_sync() is starting off in a
> > > kernel context. It shouldn't be calling add_sample() until we've had a
> > > clear indication of kernel mode or we get an mm to use. Good spot.
> > In sb_buffer_start state all samples are ignored. add_sample() is only
> > called for states b_bt_start and b_sample_start.
> Misread the code. I don't think there's a bug here then - nothing can
> move us into a state where we log samples without moving into a suitable
> context first.
Right, the above should work.
Again, I am not sure if backtraces are safe. If the number of
available entries does not match with the and of a backtrace, then the
remaining backtrace will be interpreted as samples. (Though this
should not happen, since the cpu buffer is written atomically in the
Advanced Micro Devices, Inc.
Operating System Research Center