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kasan: Zero shadow memory on memory hotplug

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Vmalloc does not zero memory by default. In this instance,
CONFIG_PAGE_POISONING was enabled, so the pages were initialized
to 0xAA.

 kasan_report+0x28c/0x2f8
 check_memory_region+0x1dc/0x1e8
 memset+0x2c/0x50
 kernel_poison_pages+0x234/0x398
 __free_pages_ok+0x380/0xd50
 __free_pages+0x4c/0xd0
 online_pages_range+0x174/0x1c8
 walk_system_ram_range+0x130/0x170
 online_pages+0x298/0x458
 memory_block_change_state+0x160/0x210
 memory_subsys_online+0x68/0x90
 device_online+0x9c/0xc8
 add_memory_resource+0x18c/0x228
 add_memory+0x118/0x180

Memory state around the buggy address:
  ffffffc17fffff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  ffffffc17fffff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 >ffffffc180000000: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
                   ^
  ffffffc180000080: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
  ffffffc180000100: aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa

Change-Id: Id487a53d3cbe14a4ba73d43e151a51fd3162b1e0
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>
[isaacm@codeaurora.org: resolve merge conflicts]
Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>
This commit is contained in:
Patrick Daly 2019-04-23 16:15:07 -07:00 committed by Gerrit - the friendly Code Review server
parent 567264c6cb
commit 67474173e3
1 changed files with 1 additions and 1 deletions
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2
mm/kasan/common.c
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@ -700,7 +700,7 @@ static int __meminit kasan_mem_notifier(struct notifier_block *nb,
return NOTIFY_OK;
ret = __vmalloc_node_range(shadow_size, PAGE_SIZE, shadow_start,
shadow_end, GFP_KERNEL,
shadow_end, GFP_KERNEL | __GFP_ZERO,
PAGE_KERNEL, VM_NO_GUARD,
pfn_to_nid(mem_data->start_pfn),
__builtin_return_address(0));