]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
arm64: mm: avoid calling apply_to_page_range on empty range
authorMika Penttilä <mika.penttila@nextfour.com>
Tue, 26 Jan 2016 15:47:25 +0000 (15:47 +0000)
committerWill Deacon <will.deacon@arm.com>
Tue, 26 Jan 2016 15:56:44 +0000 (15:56 +0000)
commit57adec866c0440976c96a4b8f5b59fb411b1cacb
tree704d55bf1775027161daf3c01cb373fc8e719a89
parent531d3067314f63d80936c565dcd0fa01c7a1760f
arm64: mm: avoid calling apply_to_page_range on empty range

Calling apply_to_page_range with an empty range results in a BUG_ON
from the core code. This can be triggered by trying to load the st_drv
module with CONFIG_DEBUG_SET_MODULE_RONX enabled:

  kernel BUG at mm/memory.c:1874!
  Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
  Modules linked in:
  CPU: 3 PID: 1764 Comm: insmod Not tainted 4.5.0-rc1+ #2
  Hardware name: ARM Juno development board (r0) (DT)
  task: ffffffc9763b8000 ti: ffffffc975af8000 task.ti: ffffffc975af8000
  PC is at apply_to_page_range+0x2cc/0x2d0
  LR is at change_memory_common+0x80/0x108

This patch fixes the issue by making change_memory_common (called by the
set_memory_* functions) a NOP when numpages == 0, therefore avoiding the
erroneous call to apply_to_page_range and bringing us into line with x86
and s390.

Cc: <stable@vger.kernel.org>
Reviewed-by: Laura Abbott <labbott@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Mika Penttilä <mika.penttila@nextfour.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
arch/arm64/mm/pageattr.c