linux-toradex.git/include/linux/poison.h, branch v4.4-rc6

include/linux/poison.h: remove not-used poison pointer macros

2015-09-10T20:29:01+00:00

Signed-off-by: Vasily Kulikov 
Cc: Solar Designer 
Cc: Thomas Gleixner 
Cc: "Kirill A. Shutemov" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

include/linux/poison.h: fix LIST_POISON{1,2} offset

2015-09-10T20:29:01+00:00

Poison pointer values should be small enough to find a room in
non-mmap'able/hardly-mmap'able space.  E.g.  on x86 "poison pointer space"
is located starting from 0x0.  Given unprivileged users cannot mmap
anything below mmap_min_addr, it should be safe to use poison pointers
lower than mmap_min_addr.

The current poison pointer values of LIST_POISON{1,2} might be too big for
mmap_min_addr values equal or less than 1 MB (common case, e.g.  Ubuntu
uses only 0x10000).  There is little point to use such a big value given
the "poison pointer space" below 1 MB is not yet exhausted.  Changing it
to a smaller value solves the problem for small mmap_min_addr setups.

The values are suggested by Solar Designer:
http://www.openwall.com/lists/oss-security/2015/05/02/6

Signed-off-by: Vasily Kulikov 
Cc: Solar Designer 
Cc: Thomas Gleixner 
Cc: "Kirill A. Shutemov" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memblock: Kill sentinel entries at the end of static region arrays

2011-12-08T18:22:07+00:00

memblock no longer depends on having one more entry at the end during
addition making the sentinel entries at the end of region arrays not
too useful.  Remove the sentinels.  This eases further updates.

Signed-off-by: Tejun Heo 
Cc: Benjamin Herrenschmidt 
Cc: Yinghai Lu

mm/memblock.c: avoid abuse of RED_INACTIVE

2011-07-26T03:57:09+00:00

RED_INACTIVE is a slab thing, and reusing it for memblock was
inappropriate, because memblock is dealing with phys_addr_t's which have a
Kconfigurable sizeof().

Create a new poison type for this application.  Fixes the sparse warning

    warning: cast truncates bits from constant value (9f911029d74e35b becomes 9d74e35b)

Reported-by: H Hartley Sweeten 
Tested-by: H Hartley Sweeten 
Acked-by: Pekka Enberg 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

hugetlb, rmap: add reverse mapping for hugepage

2010-08-11T07:21:15+00:00

This patch adds reverse mapping feature for hugepage by introducing
mapcount for shared/private-mapped hugepage and anon_vma for
private-mapped hugepage.

While hugepage is not currently swappable, reverse mapping can be useful
for memory error handler.

Without this patch, memory error handler cannot identify processes
using the bad hugepage nor unmap it from them. That is:
- for shared hugepage:
  we can collect processes using a hugepage through pagecache,
  but can not unmap the hugepage because of the lack of mapcount.
- for privately mapped hugepage:
  we can neither collect processes nor unmap the hugepage.
This patch solves these problems.

This patch include the bug fix given by commit 23be7468e8, so reverts it.

Dependency:
  "hugetlb: move definition of is_vm_hugetlb_page() to hugepage_inline.h"

ChangeLog since May 24.
- create hugetlb_inline.h and move is_vm_hugetlb_index() in it.
- move functions setting up anon_vma for hugepage into mm/rmap.c.

ChangeLog since May 13.
- rebased to 2.6.34
- fix logic error (in case that private mapping and shared mapping coexist)
- move is_vm_hugetlb_page() into include/linux/mm.h to use this function
  from linear_page_index()
- define and use linear_hugepage_index() instead of compound_order()
- use page_move_anon_rmap() in hugetlb_cow()
- copy exclusive switch of __set_page_anon_rmap() into hugepage counterpart.
- revert commit 24be7468 completely

Signed-off-by: Naoya Horiguchi 
Cc: Andi Kleen 
Cc: Andrew Morton 
Cc: Mel Gorman 
Cc: Andrea Arcangeli 
Cc: Larry Woodman 
Cc: Lee Schermerhorn 
Acked-by: Fengguang Wu 
Acked-by: Mel Gorman 
Signed-off-by: Andi Kleen

hugetlb: fix infinite loop in get_futex_key() when backed by huge pages

2010-04-24T18:31:25+00:00

If a futex key happens to be located within a huge page mapped
MAP_PRIVATE, get_futex_key() can go into an infinite loop waiting for a
page->mapping that will never exist.

See https://bugzilla.redhat.com/show_bug.cgi?id=552257 for more details
about the problem.

This patch makes page->mapping a poisoned value that includes
PAGE_MAPPING_ANON mapped MAP_PRIVATE.  This is enough for futex to
continue but because of PAGE_MAPPING_ANON, the poisoned value is not
dereferenced or used by futex.  No other part of the VM should be
dereferencing the page->mapping of a hugetlbfs page as its page cache is
not on the LRU.

This patch fixes the problem with the test case described in the bugzilla.

[akpm@linux-foundation.org: mel cant spel]
Signed-off-by: Mel Gorman 
Acked-by: Peter Zijlstra 
Acked-by: Darren Hart 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

core, x86: make LIST_POISON less deadly

2010-01-11T17:45:37+00:00

The list macros use LIST_POISON1 and LIST_POISON2 as undereferencable
pointers in order to trap erronous use of freed list_heads.  Unfortunately
userspace can arrange for those pointers to actually be dereferencable,
potentially turning an oops to an expolit.

To avoid this allow architectures (currently x86_64 only) to override
the default values for these pointers with truly-undereferencable values.
This is easy on x86_64 as the virtual address space is large and contains
areas that cannot be mapped.

Other 64-bit architectures will likely find similar unmapped ranges.

[ingo: switch to 0xdead000000000000 as the unmapped area]
[ingo: add comments, cleanup]
[jaswinder: eliminate sparse warnings]

Acked-by: Linus Torvalds 
Signed-off-by: Jaswinder Singh Rajput 
Signed-off-by: Ingo Molnar 
Signed-off-by: Avi Kivity 
Signed-off-by: Linus Torvalds

flex_array: poison free elements

2009-09-22T14:17:47+00:00

Newly initialized flex_array's and/or flex_array_part's are now poisoned
with a new poison value, FLEX_ARRAY_FREE.  It's value is similar to
POISON_FREE used in the various slab allocators, but is different to
distinguish between flex array's poisoned kmem and slab allocator poisoned
kmem.

This will allow us to identify flex_array_part's that only contain free
elements (and free them with an addition to the flex_array API).  This
could also be extended in the future to identify `get' uses on elements
that have not been `put'.

If __GFP_ZERO is passed for a part's gfp mask, the poisoning is avoided.
These elements are considered to be in-use since they have been
initialized.

Signed-off-by: David Rientjes 
Cc: Dave Hansen 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

generic debug pagealloc

2009-04-01T15:59:13+00:00

CONFIG_DEBUG_PAGEALLOC is now supported by x86, powerpc, sparc64, and
s390.  This patch implements it for the rest of the architectures by
filling the pages with poison byte patterns after free_pages() and
verifying the poison patterns before alloc_pages().

This generic one cannot detect invalid page accesses immediately but
invalid read access may cause invalid dereference by poisoned memory and
invalid write access can be detected after a long delay.

Signed-off-by: Akinobu Mita 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

debugobjects: add timer specific object debugging code

2008-04-30T15:29:53+00:00

Add calls to the generic object debugging infrastructure and provide fixup
functions which allow to keep the system alive when recoverable problems have
been detected by the object debugging core code.

Signed-off-by: Thomas Gleixner 
Acked-by: Ingo Molnar 
Cc: Greg KH 
Cc: Randy Dunlap 
Cc: Kay Sievers 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds