On Tue, 13 Jul 2021, vjitta@xxxxxxxxxxxxxx wrote:
> From: Vijayanand Jitta <vjitta@xxxxxxxxxxxxxx>
>
> Consider the scenario where CONFIG_SLUB_DEBUG_ON is set
> and we would want to disable slub_debug for few slabs.
> Using boot parameter with slub_debug=-,slab_name syntax
> doesn't work as expected i.e; only disabling debugging for
> the specified list of slabs, instead it disables debugging
> for all slabs. Fix this.
>
> Signed-off-by: Vijayanand Jitta <vjitta@xxxxxxxxxxxxxx>
> ---
> mm/slub.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/mm/slub.c b/mm/slub.c
> index dc863c1..5a88418 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -1429,6 +1429,7 @@ static int __init setup_slub_debug(char *str)
> char *slab_list;
> bool global_slub_debug_changed = false;
> bool slab_list_specified = false;
> + bool slab_list_debug_disable = true;
>
> slub_debug = DEBUG_DEFAULT_FLAGS;
> if (*str++ != '=' || !*str)
> @@ -1436,7 +1437,6 @@ static int __init setup_slub_debug(char *str)
> * No options specified. Switch on full debugging.
> */
> goto out;
> -
> saved_str = str;
> while (str) {
> str = parse_slub_debug_flags(str, &flags, &slab_list, true);
> @@ -1445,6 +1445,8 @@ static int __init setup_slub_debug(char *str)
> slub_debug = flags;
> global_slub_debug_changed = true;
> } else {
> + if (flags || !IS_ENABLED(CONFIG_SLUB_DEBUG_ON))
Could you explain the check for CONFIG_SLUB_DEBUG_ON here?
I don't believe that using `-' for slub_debug is *only* useful when
CONFIG_SLUB_DEBUG_ON is enabled.
> + slab_list_debug_disable = false;
> slab_list_specified = true;
> }
> }
> @@ -1456,7 +1458,7 @@ static int __init setup_slub_debug(char *str)
> * long as there is no option specifying flags without a slab list.
> */
> if (slab_list_specified) {
> - if (!global_slub_debug_changed)
> + if (!global_slub_debug_changed && !slab_list_debug_disable)
> slub_debug = 0;
> slub_debug_string = saved_str;
> }
