kmemleak: increase DEBUG_KMEMLEAK_EARLY_LOG_SIZE default to 16K

The current default value (400) is too low on many systems (e.g.  some
ARM64 platform takes up 1000+ entries).

syzbot uses 16000 as default value, and has proved to be enough on beefy
configurations, so let's pick that value.

This consumes more RAM on boot (each entry is 160 bytes, so in total
~2.5MB of RAM), but the memory would later be freed (early_log is
__initdata).

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Nicolas Boichat <[email protected]>
Suggested-by: Dmitry Vyukov <[email protected]>
Acked-by: Catalin Marinas <[email protected]>
Acked-by: Dmitry Vyukov <[email protected]>
Cc: Masahiro Yamada <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Petr Mladek <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Tetsuo Handa <[email protected]>
Cc: Joe Lawrence <[email protected]>
Cc: Uladzislau Rezki <[email protected]>
Cc: Andy Shevchenko <[email protected]>
Cc: Stephen Rothwell <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

lib/Kconfig.debug

@@ -580,7 +580,7 @@ config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
 	int "Maximum kmemleak early log entries"
 	depends on DEBUG_KMEMLEAK
 	range 200 40000
-	default 400
+	default 16000
 	help
 	  Kmemleak must track all the memory allocations to avoid
 	  reporting false positives. Since memory may be allocated or