The patch titled
Subject: mm: slub: fix slub_debug disabling for list of slabs
has been added to the -mm tree. Its filename is
mm-slub-fix-slub_debug-disabling-for-list-of-slabs.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-slub-fix-slub_debug-disabling-for-list-of-slabs.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-slub-fix-slub_debug-disabling-for-list-of-slabs.patch
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------------------------------------------------------
From: Vlastimil Babka <vbabka@xxxxxxx>
Subject: mm: slub: fix slub_debug disabling for list of slabs
Vijayanand Jitta reports:
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, which is wrong.
This patch fixes it by delaying the moment when the global slub_debug
flags variable is updated. In case a "slub_debug=-,slab_name" has been
passed, the global flags remain as initialized (depending on
CONFIG_SLUB_DEBUG_ON enabled or disabled) and are not simply reset to 0.
Link: https://lkml.kernel.org/r/8a3d992a-473a-467b-28a0-4ad2ff60ab82@xxxxxxx
Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
Reported-by: Vijayanand Jitta <vjitta@xxxxxxxxxxxxxx>
Reviewed-by: Vijayanand Jitta <vjitta@xxxxxxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/slub.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
--- a/mm/slub.c~mm-slub-fix-slub_debug-disabling-for-list-of-slabs
+++ a/mm/slub.c
@@ -1400,12 +1400,13 @@ check_slabs:
static int __init setup_slub_debug(char *str)
{
slab_flags_t flags;
+ slab_flags_t global_flags;
char *saved_str;
char *slab_list;
bool global_slub_debug_changed = false;
bool slab_list_specified = false;
- slub_debug = DEBUG_DEFAULT_FLAGS;
+ global_flags = DEBUG_DEFAULT_FLAGS;
if (*str++ != '=' || !*str)
/*
* No options specified. Switch on full debugging.
@@ -1417,7 +1418,7 @@ static int __init setup_slub_debug(char
str = parse_slub_debug_flags(str, &flags, &slab_list, true);
if (!slab_list) {
- slub_debug = flags;
+ global_flags = flags;
global_slub_debug_changed = true;
} else {
slab_list_specified = true;
@@ -1426,16 +1427,18 @@ static int __init setup_slub_debug(char
/*
* For backwards compatibility, a single list of flags with list of
- * slabs means debugging is only enabled for those slabs, so the global
- * slub_debug should be 0. We can extended that to multiple lists as
+ * slabs means debugging is only changed for those slabs, so the global
+ * slub_debug should be unchanged (0 or DEBUG_DEFAULT_FLAGS, depending
+ * on CONFIG_SLUB_DEBUG_ON). We can extended that to multiple lists as
* long as there is no option specifying flags without a slab list.
*/
if (slab_list_specified) {
if (!global_slub_debug_changed)
- slub_debug = 0;
+ global_flags = slub_debug;
slub_debug_string = saved_str;
}
out:
+ slub_debug = global_flags;
if (slub_debug != 0 || slub_debug_string)
static_branch_enable(&slub_debug_enabled);
else
_
Patches currently in -mm which might be from vbabka@xxxxxxx are
mm-slub-fix-slub_debug-disabling-for-list-of-slabs.patch
