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| author | Arseny Solokha <asolokha@kb.kras.ru> | 2015-01-30 13:08:27 +0100 |
|---|---|---|
| committer | Scott Wood <scottwood@freescale.com> | 2015-01-31 01:39:00 +0100 |
| commit | 0dc294f717d41bfbafc746a7a96a7bc0f114c20c (patch) | |
| tree | fa98880b9e87e95c9b4f94546020df14d95e36e7 /arch/powerpc | |
| parent | powerpc: defconfigs: add MTD_SPI_NOR (new dependency for M25P80) (diff) | |
| download | linux-0dc294f717d41bfbafc746a7a96a7bc0f114c20c.tar.xz linux-0dc294f717d41bfbafc746a7a96a7bc0f114c20c.zip | |
powerpc/mm: bail out early when flushing TLB page
MMU_NO_CONTEXT is conditionally defined as 0 or (unsigned int)-1. However,
in __flush_tlb_page() a corresponding variable is only tested for open
coded 0, which can cause NULL pointer dereference if `mm' argument was
legitimately passed as such.
Bail out early in case the first argument is NULL, thus eliminate confusion
between different values of MMU_NO_CONTEXT and avoid disabling and then
re-enabling preemption unnecessarily.
Signed-off-by: Arseny Solokha <asolokha@kb.kras.ru>
Signed-off-by: Scott Wood <scottwood@freescale.com>
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/mm/tlb_nohash.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/powerpc/mm/tlb_nohash.c b/arch/powerpc/mm/tlb_nohash.c index f38ea4df6a85..ab0616b0e6c2 100644 --- a/arch/powerpc/mm/tlb_nohash.c +++ b/arch/powerpc/mm/tlb_nohash.c @@ -284,8 +284,11 @@ void __flush_tlb_page(struct mm_struct *mm, unsigned long vmaddr, struct cpumask *cpu_mask; unsigned int pid; + if (unlikely(!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); |