[kernel] r18271 - in dists/squeeze/linux-2.6/debian: . patches/bugfix/all patches/series
Ben Hutchings
benh at alioth.debian.org
Mon Nov 14 04:23:36 UTC 2011
Author: benh
Date: Mon Nov 14 04:23:33 2011
New Revision: 18271
Log:
mm: avoid null pointer access in vm_struct via /proc/vmallocinfo
Added:
dists/squeeze/linux-2.6/debian/patches/bugfix/all/mm-avoid-null-pointer-access-in-vm_struct-via-proc-v.patch
Modified:
dists/squeeze/linux-2.6/debian/changelog
dists/squeeze/linux-2.6/debian/patches/series/40
Modified: dists/squeeze/linux-2.6/debian/changelog
==============================================================================
--- dists/squeeze/linux-2.6/debian/changelog Sun Nov 13 22:45:11 2011 (r18270)
+++ dists/squeeze/linux-2.6/debian/changelog Mon Nov 14 04:23:33 2011 (r18271)
@@ -28,6 +28,7 @@
http://www.kernel.org/pub/linux/kernel/v2.6/longterm/v2.6.32/ChangeLog-2.6.32.47
http://www.kernel.org/pub/linux/kernel/v2.6/longterm/v2.6.32/ChangeLog-2.6.32.48
and the bug report which this closes: #647624.
+ * mm: avoid null pointer access in vm_struct via /proc/vmallocinfo
-- Ben Hutchings <ben at decadent.org.uk> Thu, 10 Nov 2011 02:28:55 +0000
Added: dists/squeeze/linux-2.6/debian/patches/bugfix/all/mm-avoid-null-pointer-access-in-vm_struct-via-proc-v.patch
==============================================================================
--- /dev/null 00:00:00 1970 (empty, because file is newly added)
+++ dists/squeeze/linux-2.6/debian/patches/bugfix/all/mm-avoid-null-pointer-access-in-vm_struct-via-proc-v.patch Mon Nov 14 04:23:33 2011 (r18271)
@@ -0,0 +1,174 @@
+From: Mitsuo Hayasaka <mitsuo.hayasaka.hu at hitachi.com>
+Date: Thu, 10 Nov 2011 13:37:16 +0900
+Subject: [PATCH] [2.6.32-stable] mm: avoid null pointer access in vm_struct
+ via /proc/vmallocinfo
+
+commit f5252e009d5b87071a919221e4f6624184005368 upstream.
+
+This patch is the backport version of the patch which solves a null
+pointer access in vm_struct via /proc/vmallocinfo.
+
+The /proc/vmallocinfo shows information about vmalloc allocations in vmlist
+that is a linklist of vm_struct. It, however, may access pages field of
+vm_struct where a page was not allocated. This results in a null pointer
+access and leads to a kernel panic.
+
+Why this happen:
+In __vmalloc_node() called from vmalloc(), newly allocated vm_struct
+is added to vmlist at __get_vm_area_node() and then, some fields of
+vm_struct such as nr_pages and pages are set at __vmalloc_area_node(). In
+other words, it is added to vmlist before it is fully initialized. At the
+same time, when the /proc/vmallocinfo is read, it accesses the pages field
+of vm_struct according to the nr_pages field at show_numa_info(). Thus, a
+null pointer access happens.
+
+Patch:
+This patch adds newly allocated vm_struct to the vmlist *after* it is fully
+initialized. So, it can avoid accessing the pages field with unallocated
+page when show_numa_info() is called.
+
+Signed-off-by: Mitsuo Hayasaka <mitsuo.hayasaka.hu at hitachi.com>
+Cc: Andrew Morton <akpm at linux-foundation.org>
+Cc: David Rientjes <rientjes at google.com>
+Cc: Namhyung Kim <namhyung at gmail.com>
+Cc: "Paul E. McKenney" <paulmck at linux.vnet.ibm.com>
+Cc: Jeremy Fitzhardinge <jeremy.fitzhardinge at citrix.com>
+---
+
+ include/linux/vmalloc.h | 1 +
+ mm/vmalloc.c | 67 +++++++++++++++++++++++++++++++++++------------
+ 2 files changed, 51 insertions(+), 17 deletions(-)
+
+diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
+index 3c123c3..819a634 100644
+--- a/include/linux/vmalloc.h
++++ b/include/linux/vmalloc.h
+@@ -13,6 +13,7 @@ struct vm_area_struct; /* vma defining user mapping in mm_types.h */
+ #define VM_MAP 0x00000004 /* vmap()ed pages */
+ #define VM_USERMAP 0x00000008 /* suitable for remap_vmalloc_range */
+ #define VM_VPAGES 0x00000010 /* buffer for pages was vmalloc'ed */
++#define VM_UNLIST 0x00000020 /* vm_struct is not listed in vmlist */
+ /* bits [20..32] reserved for arch specific ioremap internals */
+
+ /*
+diff --git a/mm/vmalloc.c b/mm/vmalloc.c
+index 7221e9e..f34ffd0 100644
+--- a/mm/vmalloc.c
++++ b/mm/vmalloc.c
+@@ -1203,17 +1203,22 @@ EXPORT_SYMBOL_GPL(map_vm_area);
+ DEFINE_RWLOCK(vmlist_lock);
+ struct vm_struct *vmlist;
+
+-static void insert_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va,
++static void setup_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va,
+ unsigned long flags, void *caller)
+ {
+- struct vm_struct *tmp, **p;
+-
+ vm->flags = flags;
+ vm->addr = (void *)va->va_start;
+ vm->size = va->va_end - va->va_start;
+ vm->caller = caller;
+ va->private = vm;
+ va->flags |= VM_VM_AREA;
++}
++
++static void insert_vmalloc_vmlist(struct vm_struct *vm)
++{
++ struct vm_struct *tmp, **p;
++
++ vm->flags &= ~VM_UNLIST;
+
+ write_lock(&vmlist_lock);
+ for (p = &vmlist; (tmp = *p) != NULL; p = &tmp->next) {
+@@ -1225,6 +1230,13 @@ static void insert_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va,
+ write_unlock(&vmlist_lock);
+ }
+
++static void insert_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va,
++ unsigned long flags, void *caller)
++{
++ setup_vmalloc_vm(vm, va, flags, caller);
++ insert_vmalloc_vmlist(vm);
++}
++
+ static struct vm_struct *__get_vm_area_node(unsigned long size,
+ unsigned long align, unsigned long flags, unsigned long start,
+ unsigned long end, int node, gfp_t gfp_mask, void *caller)
+@@ -1263,7 +1275,18 @@ static struct vm_struct *__get_vm_area_node(unsigned long size,
+ return NULL;
+ }
+
+- insert_vmalloc_vm(area, va, flags, caller);
++ /*
++ * When this function is called from __vmalloc_node,
++ * we do not add vm_struct to vmlist here to avoid
++ * accessing uninitialized members of vm_struct such as
++ * pages and nr_pages fields. They will be set later.
++ * To distinguish it from others, we use a VM_UNLIST flag.
++ */
++ if (flags & VM_UNLIST)
++ setup_vmalloc_vm(area, va, flags, caller);
++ else
++ insert_vmalloc_vm(area, va, flags, caller);
++
+ return area;
+ }
+
+@@ -1338,17 +1361,20 @@ struct vm_struct *remove_vm_area(const void *addr)
+ va = find_vmap_area((unsigned long)addr);
+ if (va && va->flags & VM_VM_AREA) {
+ struct vm_struct *vm = va->private;
+- struct vm_struct *tmp, **p;
+- /*
+- * remove from list and disallow access to this vm_struct
+- * before unmap. (address range confliction is maintained by
+- * vmap.)
+- */
+- write_lock(&vmlist_lock);
+- for (p = &vmlist; (tmp = *p) != vm; p = &tmp->next)
+- ;
+- *p = tmp->next;
+- write_unlock(&vmlist_lock);
++
++ if (!(vm->flags & VM_UNLIST)) {
++ struct vm_struct *tmp, **p;
++ /*
++ * remove from list and disallow access to
++ * this vm_struct before unmap. (address range
++ * confliction is maintained by vmap.)
++ */
++ write_lock(&vmlist_lock);
++ for (p = &vmlist; (tmp = *p) != vm; p = &tmp->next)
++ ;
++ *p = tmp->next;
++ write_unlock(&vmlist_lock);
++ }
+
+ vmap_debug_free_range(va->va_start, va->va_end);
+ free_unmap_vmap_area(va);
+@@ -1568,8 +1594,9 @@ static void *__vmalloc_node(unsigned long size, unsigned long align,
+ if (!size || (size >> PAGE_SHIFT) > totalram_pages)
+ return NULL;
+
+- area = __get_vm_area_node(size, align, VM_ALLOC, VMALLOC_START,
+- VMALLOC_END, node, gfp_mask, caller);
++ area = __get_vm_area_node(size, align, VM_ALLOC | VM_UNLIST,
++ VMALLOC_START, VMALLOC_END, node,
++ gfp_mask, caller);
+
+ if (!area)
+ return NULL;
+@@ -1577,6 +1604,12 @@ static void *__vmalloc_node(unsigned long size, unsigned long align,
+ addr = __vmalloc_area_node(area, gfp_mask, prot, node, caller);
+
+ /*
++ * In this function, newly allocated vm_struct is not added
++ * to vmlist at __get_vm_area_node(). so, it is added here.
++ */
++ insert_vmalloc_vmlist(area);
++
++ /*
+ * A ref_count = 3 is needed because the vm_struct and vmap_area
+ * structures allocated in the __get_vm_area_node() function contain
+ * references to the virtual address of the vmalloc'ed block.
Modified: dists/squeeze/linux-2.6/debian/patches/series/40
==============================================================================
--- dists/squeeze/linux-2.6/debian/patches/series/40 Sun Nov 13 22:45:11 2011 (r18270)
+++ dists/squeeze/linux-2.6/debian/patches/series/40 Mon Nov 14 04:23:33 2011 (r18271)
@@ -21,3 +21,4 @@
+ bugfix/all/revert-xen-use-IRQF_FORCE_RESUME.patch
+ debian/time-Avoid-ABI-change-in-2.6.32.47.patch
+ bugfix/sparc/sparc-sigutil-Include-linux-errno.h.patch
++ bugfix/all/mm-avoid-null-pointer-access-in-vm_struct-via-proc-v.patch
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