Re: [PATCH v2 1/4] locktorture: Add nested_[un]lock() hooks and nlocks parameter

[Davidlohr Bueso]

On Fri, 03 Feb 2023, John Stultz wrote:

> In order ot extend locktorture to support lock nesting, add
	  ^ to

> nested_lock() and nested_unlock() hooks to the torture ops.
>
> These take a 32bit lockset mask which is generated at random,
> so some number of locks will be taken before the main lock is
> taken and released afterwards.
>
> Additionally, add nlocks module parameter to allow specifying
> the number of nested locks to be used.
>
> This has been helpful to uncover issues in the proxy-exec
> series development.
>
> This was inspired by locktorture extensions originally implemented
> by Connor O'Brien, for stress testing the proxy-execution series:
>  https://lore.kernel.org/lkml/20221003214501.2050087-12-connoro@xxxxxxxxxx/
>
> Comments or feedback would be greatly appreciated!

Both of the above statements should be in a cover letter patch.

> Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx>
> Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxx>
> Cc: Josh Triplett <josh@xxxxxxxxxxxxxxxx>
> Cc: Joel Fernandes <joel@xxxxxxxxxxxxxxxxx>
> Cc: Juri Lelli <juri.lelli@xxxxxxxxxx>
> Cc: Valentin Schneider <vschneid@xxxxxxxxxx>
> Cc: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
> Signed-off-by: John Stultz <jstultz@xxxxxxxxxx>

Reviewed-by: Davidlohr Bueso <dave@xxxxxxxxxxxx>

With some small nits below.

> ---
> kernel/locking/locktorture.c | 23 +++++++++++++++++++----
> 1 file changed, 19 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
> index 9c2fb613a55d..f4fbd3194654 100644
> --- a/kernel/locking/locktorture.c
> +++ b/kernel/locking/locktorture.c
> @@ -48,6 +48,9 @@ torture_param(int, stat_interval, 60,
> torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");
> torture_param(int, verbose, 1,
> 	     "Enable verbose debugging printk()s");
> +torture_param(int, nlocks, 0, "Number of nested locks");

Maybe rename the parameter to 'nested_locks'? It would also be good to
inform the 8 limit. "Number of nested locks (max = 8)".