From: Peter Zijlstra <peterz@infradead.org>
To: Chuck Ebbert <cebbert@redhat.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Ingo Molnar <mingo@elte.hu>
Subject: Re: [PATCH] mm: fix unmap_atomic range checks
Date: Fri, 24 Jun 2011 09:53:49 +0200 [thread overview]
Message-ID: <1308902029.27849.16.camel@twins> (raw)
In-Reply-To: <20110624025335.21811fef@katamari>
On Fri, 2011-06-24 at 02:53 -0400, Chuck Ebbert wrote:
> Commit 3e4d3af501cccdc8a8cca41bdbe57d54ad7e7e73 ("mm: stack based
> kmap_atomic()", in 2.6.37-rc1) had three places where range checking
> logic was reversed.
Where's the oopses to go along with this?
I think its actually correct, since on both x86 and tile we have:
#define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT))
Which flips the address space around, ie, END < BEGIN.
> Signed-off-by: Chuck Ebbert <cebbert@redhat.com>
>
> --- a/arch/tile/mm/highmem.c
> +++ b/arch/tile/mm/highmem.c
> @@ -235,8 +235,8 @@ void __kunmap_atomic(void *kvaddr)
> {
> unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
>
> - if (vaddr >= __fix_to_virt(FIX_KMAP_END) &&
> - vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) {
> + if (vaddr >= __fix_to_virt(FIX_KMAP_BEGIN) &&
> + vaddr <= __fix_to_virt(FIX_KMAP_END)) {
> pte_t *pte = kmap_get_pte(vaddr);
> pte_t pteval = *pte;
> int idx, type;
> --- a/arch/x86/mm/highmem_32.c
> +++ b/arch/x86/mm/highmem_32.c
> @@ -70,8 +70,8 @@ void __kunmap_atomic(void *kvaddr)
> {
> unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
>
> - if (vaddr >= __fix_to_virt(FIX_KMAP_END) &&
> - vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) {
> + if (vaddr >= __fix_to_virt(FIX_KMAP_BEGIN) &&
> + vaddr <= __fix_to_virt(FIX_KMAP_END)) {
> int idx, type;
>
> type = kmap_atomic_idx();
> --- a/arch/x86/mm/iomap_32.c
> +++ b/arch/x86/mm/iomap_32.c
> @@ -94,8 +94,8 @@ iounmap_atomic(void __iomem *kvaddr)
> {
> unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
>
> - if (vaddr >= __fix_to_virt(FIX_KMAP_END) &&
> - vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) {
> + if (vaddr >= __fix_to_virt(FIX_KMAP_BEGIN) &&
> + vaddr <= __fix_to_virt(FIX_KMAP_END)) {
> int idx, type;
>
> type = kmap_atomic_idx();
--
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prev parent reply other threads:[~2011-06-24 7:54 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-24 6:53 [PATCH] mm: fix unmap_atomic range checks Chuck Ebbert
2011-06-24 7:53 ` Peter Zijlstra [this message]
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