From: Vlastimil Babka
mainline inclusion
from mainline-5.14-rc6
commit a7f1d48585b34730765dcda09ead6edc4ac16a5c
category: bugfix
issue: #I4NRS5
CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
Signed-off-by: Yu Changchun
------------------------------------------------
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@suse.cz
Signed-off-by: Vlastimil Babka
Reported-by: Vijayanand Jitta
Reviewed-by: Vijayanand Jitta
Acked-by: David Rientjes
Cc: Christoph Lameter
Cc: Pekka Enberg
Cc: Joonsoo Kim
Cc: Vinayak Menon
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
Conflicts:
mm/slub.c
Signed-off-by: Jing Xiangfeng
Reviewed-by: Chen Wandun
Signed-off-by: Chen Jun
Signed-off-by: Zheng Zengkai
Signed-off-by: Yu Changchun
---
mm/slub.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/mm/slub.c b/mm/slub.c
index 1384dc906833..e6c532123de1 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1346,12 +1346,13 @@ parse_slub_debug_flags(char *str, slab_flags_t *flags, char **slabs, bool init)
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.
@@ -1363,7 +1364,7 @@ static int __init setup_slub_debug(char *str)
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;
@@ -1372,16 +1373,18 @@ static int __init setup_slub_debug(char *str)
/*
* 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);
if ((static_branch_unlikely(&init_on_alloc) ||
--
2.25.1
