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Linus Torvalds d7824370e2 mm: fix up some user-visible effects of the stack guard page 
This commit makes the stack guard page somewhat less visible to user
space. It does this by:

 - not showing the guard page in /proc/<pid>/maps

   It looks like lvm-tools will actually read /proc/self/maps to figure
   out where all its mappings are, and effectively do a specialized
   "mlockall()" in user space.  By not showing the guard page as part of
   the mapping (by just adding PAGE_SIZE to the start for grows-up
   pages), lvm-tools ends up not being aware of it.

 - by also teaching the _real_ mlock() functionality not to try to lock
   the guard page.

   That would just expand the mapping down to create a new guard page,
   so there really is no point in trying to lock it in place.

It would perhaps be nice to show the guard page specially in
/proc/<pid>/maps (or at least mark grow-down segments some way), but
let's not open ourselves up to more breakage by user space from programs
that depends on the exact deails of the 'maps' file.

Special thanks to Henrique de Moraes Holschuh for diving into lvm-tools
source code to see what was going on with the whole new warning.

Reported-and-tested-by: François Valenduc <francois.valenduc@tvcablenet.be
Reported-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-15 11:35:52 -07:00
..
backing-dev.c writeback: avoid unnecessary calculation of bdi dirty thresholds 2010-08-12 08:43:29 -07:00
bootmem.c x86,nobootmem: make alloc_bootmem_node fall back to other node when 32bit numa is used 2010-07-20 16:25:40 -07:00
bounce.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
compaction.c mm: compaction: add a tunable that decides when memory should be compacted and when it should be reclaimed 2010-05-25 08:06:59 -07:00
debug-pagealloc.c
dmapool.c
fadvise.c readahead: introduce FMODE_RANDOM for POSIX_FADV_RANDOM 2010-03-06 11:26:25 -08:00
failslab.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
filemap_xip.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
filemap.c gcc-4.6: mm: fix unused but set warnings 2010-08-09 20:44:58 -07:00
fremap.c mm: clean up mm_counter 2010-03-06 11:26:23 -08:00
highmem.c mm,kdb,kgdb: Add a debug reference for the kdb kmap usage 2010-08-05 09:22:24 -05:00
hugetlb.c Merge branch 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6 2010-08-12 10:15:10 -07:00
hwpoison-inject.c HWPOISON, hugetlb: support hwpoison injection for hugepage 2010-08-11 09:23:11 +02:00
init-mm.c mm: provide init_mm mm_context initializer 2010-08-09 20:44:54 -07:00
internal.h
Kconfig lmb: rename to memblock 2010-07-14 17:14:00 +10:00
Kconfig.debug
kmemcheck.c kmemcheck: Fix build errors due to missing slab.h 2010-03-30 22:02:32 +09:00
kmemleak-test.c
kmemleak.c kmemleak: Fix typo in the comment 2010-08-08 21:57:23 +01:00
ksm.c ksm: cleanup for mm_slots_hash 2010-08-09 20:45:03 -07:00
maccess.c
madvise.c
Makefile lmb: rename to memblock 2010-07-14 17:14:00 +10:00
memblock.c memblock: Fix memblock_is_region_reserved() to return a boolean 2010-08-09 11:21:38 +10:00
memcontrol.c memcg: convert to use zone_to_nid() from bare zone->zone_pgdat->node_id 2010-08-11 08:59:19 -07:00
memory_hotplug.c mem-hotplug: fix potential race while building zonelist for new populated zone 2010-05-25 08:07:02 -07:00
memory-failure.c Merge branch 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6 2010-08-12 10:15:10 -07:00
memory.c mm: fix page table unmap for stack guard page properly 2010-08-14 11:44:56 -07:00
mempolicy.c mempolicy: reduce stack size of migrate_pages() 2010-08-09 20:44:58 -07:00
mempool.c
migrate.c mm: extend KSM refcounts to the anon_vma root 2010-08-09 20:44:55 -07:00
mincore.c mincore: do nested page table walks 2010-05-25 08:06:58 -07:00
mlock.c mm: fix up some user-visible effects of the stack guard page 2010-08-15 11:35:52 -07:00
mm_init.c
mmap.c mmap: remove unnecessary lock from __vma_link 2010-08-09 20:44:58 -07:00
mmu_context.c exit: fix oops in sync_mm_rss 2010-03-24 16:31:21 -07:00
mmu_notifier.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
mmzone.c
mprotect.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
mremap.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
msync.c sanitize vfs_fsync calling conventions 2010-05-21 18:31:21 -04:00
nommu.c NOMMU: Remove an extraneous no_printk() 2010-08-13 16:55:25 -07:00
oom_kill.c memcg: use find_lock_task_mm() in memory cgroups oom 2010-08-11 08:59:19 -07:00
page_alloc.c vmscan: kill prev_priority completely 2010-08-09 20:45:00 -07:00
page_cgroup.c kmemleak: Annotate false positive in init_section_page_cgroup() 2010-07-19 11:54:14 +01:00
page_io.c block: unify flags for struct bio and struct request 2010-08-07 18:20:39 +02:00
page_isolation.c
page-writeback.c mm/page-writeback: fix non-kernel-doc function comments 2010-08-14 16:20:59 -07:00
pagewalk.c pagemap: fix pfn calculation for hugepage 2010-04-07 08:38:04 -07:00
percpu_up.c percpu: don't implicitly include slab.h from percpu.h 2010-03-30 22:02:32 +09:00
percpu-km.c percpu: implement kernel memory based chunk allocation 2010-05-01 08:30:50 +02:00
percpu-vm.c percpu: move vmalloc based chunk management into percpu-vm.c 2010-05-01 08:30:50 +02:00
percpu.c percpu: allow limited allocation before slab is online 2010-06-27 18:50:00 +02:00
prio_tree.c
quicklist.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
readahead.c readahead.c: fix comment 2010-05-25 08:07:00 -07:00
rmap.c Merge branch 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6 2010-08-12 10:15:10 -07:00
shmem.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2010-08-10 11:26:52 -07:00
slab.c gcc-4.6: mm: fix unused but set warnings 2010-08-09 20:44:58 -07:00
slob.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6 2010-08-06 11:44:08 -07:00
slub.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6 2010-08-06 11:44:08 -07:00
sparse-vmemmap.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
sparse.c sparsemem: on no vmemmap path put mem_map on node high too 2010-05-25 08:06:56 -07:00
swap_state.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
swap.c mm: export lru_cache_add_*() to modules 2010-05-25 15:06:06 +02:00
swapfile.c hibernation: freeze swap at hibernation 2010-08-09 20:45:04 -07:00
thrash.c
truncate.c check ATTR_SIZE contraints in inode_change_ok 2010-08-09 16:47:39 -04:00
util.c mm: use memdup_user 2010-08-09 20:44:54 -07:00
vmalloc.c Merge branch 'stable/xen-swiotlb-0.8.6' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen 2010-08-12 09:09:41 -07:00
vmscan.c memcg: remove nid and zid argument from mem_cgroup_soft_limit_reclaim() 2010-08-11 08:59:19 -07:00
vmstat.c vmscan: kill prev_priority completely 2010-08-09 20:45:00 -07:00