Messages in this thread | | | Date | Mon, 4 Apr 2022 10:19:58 +0100 | From | Will Deacon <> | Subject | Re: [PATCH] arm64: mm: fix pmd_leaf() |
| |
On Sun, Apr 03, 2022 at 10:49:28AM +0800, Muchun Song wrote: > The pmd_leaf() is used to test a leaf mapped PMD, however, it misses > the PROT_NONE mapped PMD on arm64. Fix it. A real world issue [1] > caused by this was reported by Qian Cai. > > Link: https://patchwork.kernel.org/comment/24798260/ [1] > Fixes: 8aa82df3c123 ("arm64: mm: add p?d_leaf() definitions") > Reported-by: Qian Cai <quic_qiancai@quicinc.com> > Signed-off-by: Muchun Song <songmuchun@bytedance.com> > --- > arch/arm64/include/asm/pgtable.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h > index 94e147e5456c..09eaae46a19b 100644 > --- a/arch/arm64/include/asm/pgtable.h > +++ b/arch/arm64/include/asm/pgtable.h > @@ -535,7 +535,7 @@ extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, > PMD_TYPE_TABLE) > #define pmd_sect(pmd) ((pmd_val(pmd) & PMD_TYPE_MASK) == \ > PMD_TYPE_SECT) > -#define pmd_leaf(pmd) pmd_sect(pmd) > +#define pmd_leaf(pmd) (pmd_present(pmd) && !(pmd_val(pmd) & PMD_TABLE_BIT)) > #define pmd_bad(pmd) (!pmd_table(pmd)) > > #define pmd_leaf_size(pmd) (pmd_cont(pmd) ? CONT_PMD_SIZE : PMD_SIZE)
A bunch of the users of pmd_leaf() already check pmd_present() -- is it documented that we need to handle this check inside the macro? afaict x86 doesn't do this either.
Will
| |