Re: [PATCH] Fix bug in RCU torture test

Dipankar Sarma
2005-12-05T12:32:42Z

On Mon, Dec 05, 2005 at 04:28:49PM +0530, Srivatsa Vaddagiri wrote:
> While doing some test of RCU torture module, I hit a OOPS in rcu_do_batch,
> which was trying to processes callback of a module that was just removed.
> This is because we weren't waiting long enough for all callbacks to fire.
>
> diff -puN kernel/rcutorture.c~rcutorture_fix kernel/rcutorture.c
> --- linux-2.6.15-rc5-mm1/kernel/rcutorture.c~rcutorture_fix 2005-12-05 15:33:06.000000000 +0530
> +++ linux-2.6.15-rc5-mm1-root/kernel/rcutorture.c 2005-12-05 15:33:17.000000000 +0530
> @@ -408,9 +408,8 @@ rcu_torture_cleanup(void)
> stats_task = NULL;
>
> /* Wait for all RCU callbacks to fire. */
> + rcu_barrier();

Andrew,

This patch is dependent on the rcu_barrier patch buried in reiser4
patchset. It makes sense to merge that patch without waiting
for reiser4 since rcutorture is already in mainline.
I will send an updated documentation patch describing why
and how modules using RCU should use rcu_barrier().

Thanks
Dipankar