[PATCH] powerpc/mm: add sanity check to avoid null pointer dereference
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STALE1515d
From: Defang Bo <hidden>
Date: 2020-12-28 03:17:34
Also in:
lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
Similar to commit<0dc294f717d4>("powerpc/mm: bail out early when flushing TLB page"),
there should be a check for 'mm' to prevent Null pointer dereference
in case of 'mm' argument was legitimately passed.
Signed-off-by: Defang Bo <redacted>
---
arch/powerpc/mm/nohash/tlb.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/mm/nohash/tlb.c b/arch/powerpc/mm/nohash/tlb.c
index 5872f69..1d89335 100644
--- a/arch/powerpc/mm/nohash/tlb.c
+++ b/arch/powerpc/mm/nohash/tlb.c@@ -192,6 +192,9 @@ void local_flush_tlb_mm(struct mm_struct *mm) { unsigned int pid; + if (WARN_ON(!mm)) + return; + preempt_disable(); pid = mm->context.id; if (pid != MMU_NO_CONTEXT)
@@ -205,8 +208,11 @@ void __local_flush_tlb_page(struct mm_struct *mm, unsigned long vmaddr, { unsigned int pid; + if (WARN_ON(!mm)) + return; + preempt_disable(); - pid = mm ? mm->context.id : 0; + pid = mm->context.id; if (pid != MMU_NO_CONTEXT) _tlbil_va(vmaddr, pid, tsize, ind); preempt_enable();
@@ -268,6 +274,9 @@ void flush_tlb_mm(struct mm_struct *mm) { unsigned int pid; + if (WARN_ON(!mm)) + return; + preempt_disable(); pid = mm->context.id; if (unlikely(pid == MMU_NO_CONTEXT))
--
2.7.4