From: Vlastimil Babka vbabka@suse.cz
mainline inclusion from mainline-5.14-rc6 commit a7f1d48585b34730765dcda09ead6edc4ac16a5c category: bugfix bugzilla: 176508 https://gitee.com/openeuler/kernel/issues/I4DDEL
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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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 vbabka@suse.cz Reported-by: Vijayanand Jitta vjitta@codeaurora.org Reviewed-by: Vijayanand Jitta vjitta@codeaurora.org Acked-by: David Rientjes rientjes@google.com Cc: Christoph Lameter cl@linux.com Cc: Pekka Enberg penberg@kernel.org Cc: Joonsoo Kim iamjoonsoo.kim@lge.com Cc: Vinayak Menon vinmenon@codeaurora.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Conflicts: mm/slub.c Signed-off-by: Jing Xiangfeng jingxiangfeng@huawei.com Reviewed-by: Chen Wandun chenwandun@huawei.com
Signed-off-by: Chen Jun chenjun102@huawei.com --- mm/slub.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/mm/slub.c b/mm/slub.c index 865b5b967619..b7f2316a513a 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1370,12 +1370,13 @@ 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. @@ -1387,7 +1388,7 @@ 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; @@ -1396,16 +1397,18 @@ 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) ||