diff options
| author | Dan Williams <dan.j.williams@intel.com> | 2017-03-10 03:16:42 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-03-10 04:01:09 +0300 |
| commit | ef947b2529f918d9606533eb9c32b187ed6a5ede (patch) | |
| tree | 802fbd6d597c8ab9ae1f2a989a61aa692117502c /arch | |
| parent | d19469e8415813cceaa494b6f538e327b9a95f3b (diff) | |
| download | linux-ef947b2529f918d9606533eb9c32b187ed6a5ede.tar.xz | |
x86, mm: fix gup_pte_range() vs DAX mappings
gup_pte_range() fails to check pte_allows_gup() before translating a DAX
pte entry, pte_devmap(), to a page. This allows writes to read-only
mappings, and bypasses the DAX cacheline dirty tracking due to missed
'mkwrite' faults. The gup_huge_pmd() path and the gup_huge_pud() path
correctly check pte_allows_gup() before checking for _devmap() entries.
Fixes: 3565fce3a659 ("mm, x86: get_user_pages() for dax mappings")
Link: http://lkml.kernel.org/r/148804251312.36605.12665024794196605053.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: Dave Hansen <dave.hansen@linux.intel.com>
Reported-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Xiong Zhou <xzhou@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/mm/gup.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/arch/x86/mm/gup.c b/arch/x86/mm/gup.c index 99c7805a9693..9d32ee608807 100644 --- a/arch/x86/mm/gup.c +++ b/arch/x86/mm/gup.c @@ -120,6 +120,11 @@ static noinline int gup_pte_range(pmd_t pmd, unsigned long addr, return 0; } + if (!pte_allows_gup(pte_val(pte), write)) { + pte_unmap(ptep); + return 0; + } + if (pte_devmap(pte)) { pgmap = get_dev_pagemap(pte_pfn(pte), pgmap); if (unlikely(!pgmap)) { @@ -127,8 +132,7 @@ static noinline int gup_pte_range(pmd_t pmd, unsigned long addr, pte_unmap(ptep); return 0; } - } else if (!pte_allows_gup(pte_val(pte), write) || - pte_special(pte)) { + } else if (pte_special(pte)) { pte_unmap(ptep); return 0; } |