| 1 |
Author: mpagano |
| 2 |
Date: 2010-08-20 13:16:49 +0000 (Fri, 20 Aug 2010) |
| 3 |
New Revision: 1754 |
| 4 |
|
| 5 |
Added: |
| 6 |
genpatches-2.6/trunk/2.6.32/1800_page-table-unmap-for-stack-guard-fix.patch |
| 7 |
Modified: |
| 8 |
genpatches-2.6/trunk/2.6.32/0000_README |
| 9 |
Log: |
| 10 |
Patch to fix page table unmap for stack guard page |
| 11 |
|
| 12 |
Modified: genpatches-2.6/trunk/2.6.32/0000_README |
| 13 |
=================================================================== |
| 14 |
--- genpatches-2.6/trunk/2.6.32/0000_README 2010-08-20 00:05:29 UTC (rev 1753) |
| 15 |
+++ genpatches-2.6/trunk/2.6.32/0000_README 2010-08-20 13:16:49 UTC (rev 1754) |
| 16 |
@@ -115,6 +115,10 @@ |
| 17 |
From: http://www.kernel.org |
| 18 |
Desc: Linux 2.6.32.19 |
| 19 |
|
| 20 |
+Patch: 1800_page-table-unmap-for-stack-guard-fix.patch |
| 21 |
+From: https://bugzilla.kernel.org/show_bug.cgi?id=16588 |
| 22 |
+Desc: Fix page table unmap for stack guard page properly |
| 23 |
+ |
| 24 |
Patch: 2500_libata-fix-truncated-LBA48-ret-vals.patch |
| 25 |
From: http://bugs.gentoo.org/show_bug.cgi?id=303313 |
| 26 |
Desc: Fix bug which truncated LBA48 return values |
| 27 |
|
| 28 |
Added: genpatches-2.6/trunk/2.6.32/1800_page-table-unmap-for-stack-guard-fix.patch |
| 29 |
=================================================================== |
| 30 |
--- genpatches-2.6/trunk/2.6.32/1800_page-table-unmap-for-stack-guard-fix.patch (rev 0) |
| 31 |
+++ genpatches-2.6/trunk/2.6.32/1800_page-table-unmap-for-stack-guard-fix.patch 2010-08-20 13:16:49 UTC (rev 1754) |
| 32 |
@@ -0,0 +1,76 @@ |
| 33 |
+From 11ac552477e32835cb6970bf0a70c210807f5673 Mon Sep 17 00:00:00 2001 |
| 34 |
+From: Linus Torvalds <torvalds@××××××××××××××××.org> |
| 35 |
+Date: Sat, 14 Aug 2010 11:44:56 -0700 |
| 36 |
+Subject: [PATCH] mm: fix page table unmap for stack guard page properly |
| 37 |
+MIME-Version: 1.0 |
| 38 |
+Content-Type: text/plain; charset=utf8 |
| 39 |
+Content-Transfer-Encoding: 8bit |
| 40 |
+ |
| 41 |
+We do in fact need to unmap the page table _before_ doing the whole |
| 42 |
+stack guard page logic, because if it is needed (mainly 32-bit x86 with |
| 43 |
+PAE and CONFIG_HIGHPTE, but other architectures may use it too) then it |
| 44 |
+will do a kmap_atomic/kunmap_atomic. |
| 45 |
+ |
| 46 |
+And those kmaps will create an atomic region that we cannot do |
| 47 |
+allocations in. However, the whole stack expand code will need to do |
| 48 |
+anon_vma_prepare() and vma_lock_anon_vma() and they cannot do that in an |
| 49 |
+atomic region. |
| 50 |
+ |
| 51 |
+Now, a better model might actually be to do the anon_vma_prepare() when |
| 52 |
+_creating_ a VM_GROWSDOWN segment, and not have to worry about any of |
| 53 |
+this at page fault time. But in the meantime, this is the |
| 54 |
+straightforward fix for the issue. |
| 55 |
+ |
| 56 |
+See https://bugzilla.kernel.org/show_bug.cgi?id=16588 for details. |
| 57 |
+ |
| 58 |
+Reported-by: Wylda <wylda@×××××.cz> |
| 59 |
+Reported-by: Sedat Dilek <sedat.dilek@×××××.com> |
| 60 |
+Reported-by: Mike Pagano <mpagano@g.o> |
| 61 |
+Reported-by: François Valenduc <francois.valenduc@××××××××××.be> |
| 62 |
+Tested-by: Ed Tomlinson <edt@×××.ca> |
| 63 |
+Cc: Pekka Enberg <penberg@××××××.org> |
| 64 |
+Cc: Greg KH <gregkh@××××.de> |
| 65 |
+Cc: stable@××××××.org |
| 66 |
+Signed-off-by: Linus Torvalds <torvalds@××××××××××××××××.org> |
| 67 |
+--- |
| 68 |
+ mm/memory.c | 13 ++++++------- |
| 69 |
+ 1 files changed, 6 insertions(+), 7 deletions(-) |
| 70 |
+ |
| 71 |
+diff --git a/mm/memory.c b/mm/memory.c |
| 72 |
+index 9b3b73f..b6e5fd2 100644 |
| 73 |
+--- a/mm/memory.c |
| 74 |
++++ b/mm/memory.c |
| 75 |
+@@ -2792,24 +2792,23 @@ static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, |
| 76 |
+ spinlock_t *ptl; |
| 77 |
+ pte_t entry; |
| 78 |
+ |
| 79 |
+- if (check_stack_guard_page(vma, address) < 0) { |
| 80 |
+- pte_unmap(page_table); |
| 81 |
++ pte_unmap(page_table); |
| 82 |
++ |
| 83 |
++ /* Check if we need to add a guard page to the stack */ |
| 84 |
++ if (check_stack_guard_page(vma, address) < 0) |
| 85 |
+ return VM_FAULT_SIGBUS; |
| 86 |
+- } |
| 87 |
+ |
| 88 |
++ /* Use the zero-page for reads */ |
| 89 |
+ if (!(flags & FAULT_FLAG_WRITE)) { |
| 90 |
+ entry = pte_mkspecial(pfn_pte(my_zero_pfn(address), |
| 91 |
+ vma->vm_page_prot)); |
| 92 |
+- ptl = pte_lockptr(mm, pmd); |
| 93 |
+- spin_lock(ptl); |
| 94 |
++ page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
| 95 |
+ if (!pte_none(*page_table)) |
| 96 |
+ goto unlock; |
| 97 |
+ goto setpte; |
| 98 |
+ } |
| 99 |
+ |
| 100 |
+ /* Allocate our own private page. */ |
| 101 |
+- pte_unmap(page_table); |
| 102 |
+- |
| 103 |
+ if (unlikely(anon_vma_prepare(vma))) |
| 104 |
+ goto oom; |
| 105 |
+ page = alloc_zeroed_user_highpage_movable(vma, address); |
| 106 |
+-- |
| 107 |
+1.7.2.2 |
| 108 |
+ |
Archives