* + x86-mm-fix-gup_pte_range-vs-dax-mappings.patch added to -mm tree
@ 2017-02-28 22:09 akpm
0 siblings, 0 replies; 2+ messages in thread
From: akpm @ 2017-02-28 22:09 UTC (permalink / raw)
To: dan.j.williams, dave.hansen, hpa, mingo, ross.zwisler, stable,
tglx, xzhou, mm-commits
The patch titled
Subject: x86, mm: fix gup_pte_range() vs DAX mappings
has been added to the -mm tree. Its filename is
x86-mm-fix-gup_pte_range-vs-dax-mappings.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/x86-mm-fix-gup_pte_range-vs-dax-mappings.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/x86-mm-fix-gup_pte_range-vs-dax-mappings.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Dan Williams <dan.j.williams@intel.com>
Subject: 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>
---
arch/x86/mm/gup.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff -puN arch/x86/mm/gup.c~x86-mm-fix-gup_pte_range-vs-dax-mappings arch/x86/mm/gup.c
--- a/arch/x86/mm/gup.c~x86-mm-fix-gup_pte_range-vs-dax-mappings
+++ a/arch/x86/mm/gup.c
@@ -120,6 +120,11 @@ static noinline int gup_pte_range(pmd_t
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
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;
}
_
Patches currently in -mm which might be from dan.j.williams@intel.com are
x86-mm-fix-gup_pte_range-vs-dax-mappings.patch
x86-mm-unify-exit-paths-in-gup_pte_range.patch
^ permalink raw reply [flat|nested] 2+ messages in thread
* + x86-mm-fix-gup_pte_range-vs-dax-mappings.patch added to -mm tree
@ 2017-02-28 22:09 akpm
0 siblings, 0 replies; 2+ messages in thread
From: akpm @ 2017-02-28 22:09 UTC (permalink / raw)
To: dan.j.williams, dave.hansen, hpa, mingo, ross.zwisler, stable,
tglx, xzhou, mm-commits
The patch titled
Subject: x86, mm: fix gup_pte_range() vs DAX mappings
has been added to the -mm tree. Its filename is
x86-mm-fix-gup_pte_range-vs-dax-mappings.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/x86-mm-fix-gup_pte_range-vs-dax-mappings.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/x86-mm-fix-gup_pte_range-vs-dax-mappings.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Dan Williams <dan.j.williams@intel.com>
Subject: 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>
---
arch/x86/mm/gup.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff -puN arch/x86/mm/gup.c~x86-mm-fix-gup_pte_range-vs-dax-mappings arch/x86/mm/gup.c
--- a/arch/x86/mm/gup.c~x86-mm-fix-gup_pte_range-vs-dax-mappings
+++ a/arch/x86/mm/gup.c
@@ -120,6 +120,11 @@ static noinline int gup_pte_range(pmd_t
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
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;
}
_
Patches currently in -mm which might be from dan.j.williams@intel.com are
x86-mm-fix-gup_pte_range-vs-dax-mappings.patch
x86-mm-unify-exit-paths-in-gup_pte_range.patch
^ permalink raw reply [flat|nested] 2+ messages in thread
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2017-02-28 22:09 + x86-mm-fix-gup_pte_range-vs-dax-mappings.patch added to -mm tree akpm
2017-02-28 22:09 akpm
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