Re: call_rcu from trace_preempt

[Alexei Starovoitov]

On 6/15/15 11:34 PM, Daniel Wagner wrote:
> On 06/16/2015 08:25 AM, Alexei Starovoitov wrote:
> > On 6/15/15 11:06 PM, Daniel Wagner wrote:
> > > > with the above 'fix' the trace.patch is now passing.
> > > It still crashes for me with the original test program
> > >
> > > [  145.908013]  [<ffffffff810d1da1>] ? __rcu_reclaim+0x101/0x3d0
> > > [  145.908013]  [<ffffffff810d1ca0>] ? rcu_barrier_func+0x250/0x250
> > > [  145.908013]  [<ffffffff810abc03>] ?
> > > trace_hardirqs_on_caller+0xf3/0x240
> > > [  145.908013]  [<ffffffff810d9afa>] rcu_do_batch+0x2ea/0x6b0
> >
> > yes. full bpf test still crashes.
> > That's why I said trace.patch is passing ;)
> > There is something else in there. One 'fix' at a time.
>
> Ah, sorry, I read it is working now :) Anyway, I'll keep looking
> as well.
>
> Yesterday I wrote a small torture program for the map
> implementation. Just to rule out memory corruption there.
> Are you interested in it? If yes I could clean it a bit.

of course!
We already have samples/bpf/test_maps.c that stresses map
access from user space and lib/test_bpf.c that stress JIT
and interpreter from the kernel.
Looking at your test, I think it doesn't buy as much doing it
from the kernel?
If so, I think would be great to add it to test_maps.c

Will read it more carefully tomorrow.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/