Function __flush_tlb_page() must only be called for user contexts, so
put in extra hardening to warn on calling it for kernel context.
Signed-off-by: Arseny Solokha <asolo...@kb.kras.ru>
---
arch/powerpc/mm/tlb_nohash.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/mm/tlb_nohash.c b/arch/powerpc/mm/tlb_nohash.c
index f38ea4d..cbd3d06 100644
--- a/arch/powerpc/mm/tlb_nohash.c
+++ b/arch/powerpc/mm/tlb_nohash.c
@@ -284,8 +284,15 @@ void __flush_tlb_page(struct mm_struct *mm, unsigned long
vmaddr,
struct cpumask *cpu_mask;
unsigned int pid;
+ /*
+ * This function as well as __local_flush_tlb_page() must only be called
+ * for user contexts.
+ */
+ if (unlikely(WARN_ON(!mm)))
+ return;
+
preempt_disable();
- pid = mm ? mm->context.id : 0;
+ pid = mm->context.id;
if (unlikely(pid == MMU_NO_CONTEXT))
goto bail;
cpu_mask = mm_cpumask(mm);
--
2.2.2
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