From: Andrey Ryabinin a.ryabinin@samsung.com
Currently memory hotplug won't work with KASan. As we don't have shadow for hotplugged memory, kernel will crash on the first access to it. To make this work we will need to allocate shadow for new memory.
At some future point proper memory hotplug support will be implemented. Until then, print a warning at startup and disable memory hot-add.
Signed-off-by: Andrey Ryabinin a.ryabinin@samsung.com Cc: Dmitry Vyukov dvyukov@google.com Cc: Konstantin Serebryany kcc@google.com Cc: Dmitry Chernenkov dmitryc@google.com Signed-off-by: Andrey Konovalov adech.fo@gmail.com Cc: Yuri Gribov tetra2005@gmail.com Cc: Konstantin Khlebnikov koct9i@gmail.com Cc: Sasha Levin sasha.levin@oracle.com Cc: Christoph Lameter cl@linux.com Cc: Joonsoo Kim iamjoonsoo.kim@lge.com Cc: Dave Hansen dave.hansen@intel.com Cc: Andi Kleen andi@firstfloor.org Cc: Ingo Molnar mingo@elte.hu Cc: Thomas Gleixner tglx@linutronix.de Cc: "H. Peter Anvin" hpa@zytor.com Cc: Christoph Lameter cl@linux.com Cc: Pekka Enberg penberg@kernel.org Cc: David Rientjes rientjes@google.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org (cherry picked from commit 786a8959912eb94fc2381c2ae487a96ce55dabca) Signed-off-by: Alex Shi alex.shi@linaro.org --- mm/kasan/kasan.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+)
diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c index 6dc1aa7..def8110 100644 --- a/mm/kasan/kasan.c +++ b/mm/kasan/kasan.c @@ -20,6 +20,7 @@ #include <linux/init.h> #include <linux/kernel.h> #include <linux/memblock.h> +#include <linux/memory.h> #include <linux/mm.h> #include <linux/printk.h> #include <linux/sched.h> @@ -300,3 +301,23 @@ EXPORT_SYMBOL(__asan_storeN_noabort); /* to shut up compiler complaints */ void __asan_handle_no_return(void) {} EXPORT_SYMBOL(__asan_handle_no_return); + +#ifdef CONFIG_MEMORY_HOTPLUG +static int kasan_mem_notifier(struct notifier_block *nb, + unsigned long action, void *data) +{ + return (action == MEM_GOING_ONLINE) ? NOTIFY_BAD : NOTIFY_OK; +} + +static int __init kasan_memhotplug_init(void) +{ + pr_err("WARNING: KASan doesn't support memory hot-add\n"); + pr_err("Memory hot-add will be disabled\n"); + + hotplug_memory_notifier(kasan_mem_notifier, 0); + + return 0; +} + +module_init(kasan_memhotplug_init); +#endif