Messages in this thread Patch in this message | | | Subject | [PATCH]highmem_32.c: add argument pointer checking | From | "Figo.zhang" <> | Date | Mon, 29 Jun 2009 11:08:26 +0800 |
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It had better add argument pointer checking.
If any guys write driver want to alloc hightmem and pass a no-initial pointer, it would be crashed.
Signed-off-by: Figo.zhang <figo1802@gmail.com> --- arch/x86/mm/highmem_32.c | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-)
diff --git a/arch/x86/mm/highmem_32.c b/arch/x86/mm/highmem_32.c index 58f621e..e52e1a9 100644 --- a/arch/x86/mm/highmem_32.c +++ b/arch/x86/mm/highmem_32.c @@ -31,6 +31,7 @@ void *kmap_atomic_prot(struct page *page, enum km_type type, pgprot_t prot) { enum fixed_addresses idx; unsigned long vaddr; + BUG_ON(!page); /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */ pagefault_disable(); @@ -58,6 +59,9 @@ void kunmap_atomic(void *kvaddr, enum km_type type) unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id(); + if(!kvaddr) + return; + /* * Force other mappings to Oops if they'll try to access this pte * without first remap it. Keeping stale mappings around is a bad idea
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