Re: [PATCH] mm: slub: Fix slub_debug disablement for list of slabs
From: Vlastimil Babka <hidden>
Date: 2021-07-26 22:32:47
Also in:
lkml
Subsystem:
memory management, slab allocator, the rest · Maintainers:
Andrew Morton, Vlastimil Babka, Harry Yoo, Linus Torvalds
On 7/13/21 1:45 PM, vjitta@codeaurora.org wrote:
From: Vijayanand Jitta <redacted> 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 <redacted>
Would the following work too, and perhaps be easier to follow? ----8<----
diff --git a/mm/slub.c b/mm/slub.c
index 090fa14628f9..024f49706386 100644
--- a/mm/slub.c
+++ b/mm/slub.c@@ -1400,12 +1400,13 @@ 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.
@@ -1417,7 +1418,7 @@ 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;
@@ -1426,16 +1427,18 @@ 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); else
--
2.32.0