mm/memblock: debug: don't free reserved array if !ARCH_DISCARD_MEMBLOCK
Now the Nobootmem allocator will always try to free memory allocated for
reserved memory regions (free_low_memory_core_early()) without taking
into to account current memblock debugging configuration
(CONFIG_ARCH_DISCARD_MEMBLOCK and CONFIG_DEBUG_FS state).
As result if:
- CONFIG_DEBUG_FS defined
- CONFIG_ARCH_DISCARD_MEMBLOCK not defined;
- reserved memory regions array have been resized during boot
then:
- memory allocated for reserved memory regions array will be freed to
buddy allocator;
- debug_fs entry "sys/kernel/debug/memblock/reserved" will show garbage
instead of state of memory reservations. like:
0: 0x98393bc0..0x9a393bbf
1: 0xff120000..0xff11ffff
2: 0x00000000..0xffffffff
Hence, do not free memory allocated for reserved memory regions if
defined(CONFIG_DEBUG_FS) && !defined(CONFIG_ARCH_DISCARD_MEMBLOCK).
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Tony Lindgren <tony@atomide.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memblock.c b/mm/memblock.c
index 6a2a48a..de4d9c3 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -269,6 +269,19 @@
if (memblock.reserved.regions == memblock_reserved_init_regions)
return 0;
+ /*
+ * Don't allow nobootmem allocator to free reserved memory regions
+ * array if
+ * - CONFIG_DEBUG_FS is enabled;
+ * - CONFIG_ARCH_DISCARD_MEMBLOCK is not enabled;
+ * - reserved memory regions array have been resized during boot.
+ * Otherwise debug_fs entry "sys/kernel/debug/memblock/reserved"
+ * will show garbage instead of state of memory reservations.
+ */
+ if (IS_ENABLED(CONFIG_DEBUG_FS) &&
+ !IS_ENABLED(CONFIG_ARCH_DISCARD_MEMBLOCK))
+ return 0;
+
*addr = __pa(memblock.reserved.regions);
return PAGE_ALIGN(sizeof(struct memblock_region) *