linux-kernel - [PATCH v2] MIPS: Fix incorrect NULL check in local_flush_tlb

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Message-Id: <1404584812-12377-1-git-send-email-emilgoode@gmail.com>
Date:	Sat,  5 Jul 2014 20:26:52 +0200
From:	Emil Goode <emilgoode@...il.com>
To:	Ralf Baechle <ralf@...ux-mips.org>,
	Paul Gortmaker <paul.gortmaker@...driver.com>,
	John Crispin <blogic@...nwrt.org>,
	Jonas Gorski <jogo@...nwrt.org>
Cc:	linux-mips@...ux-mips.org, linux-kernel@...r.kernel.org,
	kernel-janitors@...r.kernel.org, Emil Goode <emilgoode@...il.com>
Subject: [PATCH v2] MIPS: Fix incorrect NULL check in local_flush_tlb_page()

We check that the struct vm_area_struct pointer vma is NULL and then
dereference it a few lines below. The intent must have been to make sure
that vma is not NULL and then to check the value from cpu_context() for
the condition to be true.

Signed-off-by: Emil Goode <emilgoode@...il.com>
---

v2: Updated the commit message with a better explanation.

 arch/mips/mm/tlb-r3k.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/mips/mm/tlb-r3k.c b/arch/mips/mm/tlb-r3k.c
index d657493..6546758 100644
--- a/arch/mips/mm/tlb-r3k.c
+++ b/arch/mips/mm/tlb-r3k.c
@@ -158,7 +158,7 @@ void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
 {
 	int cpu = smp_processor_id();
 
-	if (!vma || cpu_context(cpu, vma->vm_mm) != 0) {
+	if (vma && cpu_context(cpu, vma->vm_mm) != 0) {
 		unsigned long flags;
 		int oldpid, newpid, idx;
 
-- 
1.7.10.4

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