]> git.baikalelectronics.ru Git - kernel.git/commit
drivers/base/memory.c: don't access uninitialized memmaps in soft_offline_page_store()
authorDavid Hildenbrand <david@redhat.com>
Sat, 19 Oct 2019 03:19:16 +0000 (20:19 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Sat, 19 Oct 2019 10:32:31 +0000 (06:32 -0400)
commit3c50aaf82d29af5832e4efa8ce5ce522b0448aa9
treed68c1be22b8fa86d688c9845af29e7ec674f1f35
parentc1173eb424e07e0f1acfbadb2a45c28edaa0ba8b
drivers/base/memory.c: don't access uninitialized memmaps in soft_offline_page_store()

Uninitialized memmaps contain garbage and in the worst case trigger kernel
BUGs, especially with CONFIG_PAGE_POISONING.  They should not get touched.

Right now, when trying to soft-offline a PFN that resides on a memory
block that was never onlined, one gets a misleading error with
CONFIG_PAGE_POISONING:

  :/# echo 5637144576 > /sys/devices/system/memory/soft_offline_page
  [   23.097167] soft offline: 0x150000 page already poisoned

But the actual result depends on the garbage in the memmap.

soft_offline_page() can only work with online pages, it returns -EIO in
case of ZONE_DEVICE.  Make sure to only forward pages that are online
(iow, managed by the buddy) and, therefore, have an initialized memmap.

Add a check against pfn_to_online_page() and similarly return -EIO.

Link: http://lkml.kernel.org/r/20191010141200.8985-1-david@redhat.com
Fixes: 6f0c7df0c956 ("mm, memory_hotplug: do not associate hotadded memory to zones until online") [visible after ce83b9d4f0076]
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: <stable@vger.kernel.org> [4.13+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/base/memory.c