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authorMika Penttilä <mika.penttila@nextfour.com>2016-01-26 15:47:25 +0000
committerWill Deacon <will.deacon@arm.com>2016-01-26 15:56:44 +0000
commit57adec866c0440976c96a4b8f5b59fb411b1cacb (patch)
tree704d55bf1775027161daf3c01cb373fc8e719a89 /arch
parent531d3067314f63d80936c565dcd0fa01c7a1760f (diff)
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>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm64/mm/pageattr.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c
index 3571c7309c5e..cf6240741134 100644
--- a/arch/arm64/mm/pageattr.c
+++ b/arch/arm64/mm/pageattr.c
@@ -57,6 +57,9 @@ static int change_memory_common(unsigned long addr, int numpages,
if (end < MODULES_VADDR || end >= MODULES_END)
return -EINVAL;
+ if (!numpages)
+ return 0;
+
data.set_mask = set_mask;
data.clear_mask = clear_mask;