David Rientjes 32f8516a8c mm, mempolicy: fix printing stack contents in numa_maps ... When reading /proc/pid/numa_maps, it's possible to return the contents of the stack where the mempolicy string should be printed if the policy gets freed from beneath us. This happens because mpol_to_str() may return an error the stack-allocated buffer is then printed without ever being stored. There are two possible error conditions in mpol_to_str(): - if the buffer allocated is insufficient for the string to be stored, and - if the mempolicy has an invalid mode. The first error condition is not triggered in any of the callers to mpol_to_str(): at least 50 bytes is always allocated on the stack and this is sufficient for the string to be written. A future patch should convert this into BUILD_BUG_ON() since we know the maximum strlen possible, but that's not -rc material. The second error condition is possible if a race occurs in dropping a reference to a task's mempolicy causing it to be freed during the read(). The slab poison value is then used for the mode and mpol_to_str() returns -EINVAL. This race is only possible because get_vma_policy() believes that mm->mmap_sem protects task->mempolicy, which isn't true. The exit path does not hold mm->mmap_sem when dropping the reference or setting task->mempolicy to NULL: it uses task_lock(task) instead. Thus, it's required for the caller of a task mempolicy to hold task_lock(task) while grabbing the mempolicy and reading it. Callers with a vma policy store their mempolicy earlier and can simply increment the reference count so it's guaranteed not to be freed. Reported-by: Dave Jones <davej@redhat.com> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2012-10-16 18:00:50 -07:00
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Kconfig	mm: enable CONFIG_COMPACTION by default	2012-10-09 16:22:53 +09:00
Kconfig.debug	mm: more intensive memory corruption debugging	2012-01-10 16:30:42 -08:00
Makefile	mm: replace vma prio_tree with an interval tree	2012-10-09 16:22:39 +09:00
backing-dev.c	backing-dev: use kstrto* in preference to simple_strtoul	2012-08-25 16:58:14 +08:00
bootmem.c	mm: fix-up zone present pages	2012-10-09 16:22:54 +09:00
bounce.c	bounce: allow use of bounce pool via config option	2012-07-18 16:40:35 -04:00
cleancache.c	->encode_fh() API change	2012-05-29 23:28:33 -04:00
compaction.c	CMA: migrate mlocked pages	2012-10-09 16:23:00 +09:00
debug-pagealloc.c	mm, x86: Remove debug_pagealloc_enabled	2011-12-06 09:24:07 +01:00
dmapool.c	mm: fix implicit stat.h usage in dmapool.c	2011-10-31 09:20:12 -04:00
fadvise.c	switch simple cases of fget_light to fdget	2012-09-26 22:20:08 -04:00
failslab.c	switch debugfs to umode_t	2012-01-03 22:54:56 -05:00
filemap.c	readahead: fault retry breaks mmap file read random detection	2012-10-09 16:22:47 +09:00
filemap_xip.c	mm: move all mmu notifier invocations to be done outside the PT lock	2012-10-09 16:22:58 +09:00
fremap.c	mm: replace vma prio_tree with an interval tree	2012-10-09 16:22:39 +09:00
frontswap.c	frontswap: support exclusive gets if tmem backend is capable	2012-09-21 10:38:12 -04:00
highmem.c	mm: add support for direct_IO to highmem pages	2012-07-31 18:42:47 -07:00
huge_memory.c	mm: huge_memory: Fix build error.	2012-10-15 07:59:15 -07:00
hugetlb.c	mm: document PageHuge somewhat	2012-10-09 16:23:03 +09:00
hugetlb_cgroup.c	hugetlb/cgroup: remove exclude and wakeup rmdir calls from migrate	2012-07-31 18:42:41 -07:00
hwpoison-inject.c	memcg: rename config variables	2012-07-31 18:42:43 -07:00
init-mm.c	atomic: use <linux/atomic.h>	2011-07-26 16:49:47 -07:00
internal.h	mm, thp: fix mlock statistics	2012-10-09 16:23:03 +09:00
interval_tree.c	mm: add CONFIG_DEBUG_VM_RB build option	2012-10-09 16:22:42 +09:00
kmemcheck.c	kmemcheck: Fix build errors due to missing slab.h	2010-03-30 22:02:32 +09:00
kmemleak-test.c	kmemleak: remove memset by using kzalloc	2011-01-27 18:31:51 +00:00
kmemleak.c	kmemleak: use rbtree instead of prio tree	2012-10-09 16:22:39 +09:00
ksm.c	mm: wrap calls to set_pte_at_notify with invalidate_range_start and invalidate_range_end	2012-10-09 16:22:58 +09:00
maccess.c	mm: Map most files to use export.h instead of module.h	2011-10-31 09:20:12 -04:00
madvise.c	mm: prepare VM_DONTDUMP for using in drivers	2012-10-09 16:22:18 +09:00
memblock.c	mm: avoid section mismatch warning for memblock_type_name	2012-10-09 16:23:01 +09:00
memcontrol.c	memcg: move mem_cgroup_is_root upwards	2012-10-09 16:22:55 +09:00
memory-failure.c	mm anon rmap: replace same_anon_vma linked list with an interval tree.	2012-10-09 16:22:41 +09:00
memory.c	mm, thp: fix mapped pages avoiding unevictable list on mlock	2012-10-09 16:23:02 +09:00
memory_hotplug.c	memory-hotplug: suppress "Trying to free nonexistent resource <XXXXXXXXXXXXXXXX-YYYYYYYYYYYYYYYY>" warning	2012-10-09 16:23:04 +09:00
mempolicy.c	mm, mempolicy: fix printing stack contents in numa_maps	2012-10-16 18:00:50 -07:00
mempool.c	mempool: add @gfp_mask to mempool_create_node()	2012-06-25 11:53:47 +02:00
migrate.c	mm: memcg: fix compaction/migration failing due to memcg limits	2012-07-31 18:42:48 -07:00
mincore.c	mm: thp: fix pmd_bad() triggering in code paths holding mmap_sem read mode	2012-03-21 17:54:54 -07:00
mlock.c	mm, thp: fix mlock statistics	2012-10-09 16:23:03 +09:00
mm_init.c	mm: Map most files to use export.h instead of module.h	2011-10-31 09:20:12 -04:00
mmap.c	mm: avoid taking rmap locks in move_ptes()	2012-10-09 16:22:42 +09:00
mmu_context.c	mm, counters: remove task argument to sync_mm_rss() and __sync_task_rss_stat()	2012-03-21 17:54:59 -07:00
mmu_notifier.c	mm: wrap calls to set_pte_at_notify with invalidate_range_start and invalidate_range_end	2012-10-09 16:22:58 +09:00
mmzone.c	memcg: rename config variables	2012-07-31 18:42:43 -07:00
mprotect.c	Merge branch 'akpm' (Andrew's patch-bomb)	2012-03-22 09:04:48 -07:00
mremap.c	mm: move all mmu notifier invocations to be done outside the PT lock	2012-10-09 16:22:58 +09:00
msync.c	sanitize vfs_fsync calling conventions	2010-05-21 18:31:21 -04:00
nobootmem.c	mm: fix-up zone present pages	2012-10-09 16:22:54 +09:00
nommu.c	mm: replace vma prio_tree with an interval tree	2012-10-09 16:22:39 +09:00
oom_kill.c	oom: remove deprecated oom_adj	2012-10-09 16:22:24 +09:00
page-writeback.c	CPU hotplug, writeback: Don't call writeback_set_ratelimit() too often during hotplug	2012-09-28 20:27:49 +08:00
page_alloc.c	cma: decrease cc.nr_migratepages after reclaiming pagelist	2012-10-09 16:23:01 +09:00
page_cgroup.c	memcg: rename config variables	2012-07-31 18:42:43 -07:00
page_io.c	mm: add support for direct_IO to highmem pages	2012-07-31 18:42:47 -07:00
page_isolation.c	mm/page_alloc: refactor out __alloc_contig_migrate_alloc()	2012-10-09 16:22:52 +09:00
pagewalk.c	mm: fix kernel-doc warnings	2012-06-20 14:39:36 -07:00
percpu-km.c	percpu: clear memory allocated with the km allocator	2010-10-02 10:28:42 +03:00
percpu-vm.c	mm: fix kernel-doc warnings	2012-06-20 14:39:36 -07:00
percpu.c	sections: fix section conflicts in mm/percpu.c	2012-10-06 03:04:44 +09:00
pgtable-generic.c	thp: introduce pmdp_invalidate()	2012-10-09 16:22:29 +09:00
process_vm_access.c	aio/vfs: cleanup of rw_copy_check_uvector() and compat_rw_copy_check_uvector()	2012-05-31 17:49:32 -07:00
quicklist.c	mm: delete various needless include <linux/module.h>	2011-10-31 09:20:11 -04:00
readahead.c	switch simple cases of fget_light to fdget	2012-09-26 22:20:08 -04:00
rmap.c	mm: move all mmu notifier invocations to be done outside the PT lock	2012-10-09 16:22:58 +09:00
shmem.c	tmpfs,ceph,gfs2,isofs,reiserfs,xfs: fix fh_len checking	2012-10-09 23:33:55 -04:00
slab.c	Merge branch 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux	2012-10-07 07:53:13 +09:00
slab.h	Revert "mm/sl[aou]b: Move sysfs_slab_add to common"	2012-09-05 12:07:44 +03:00
slab_common.c	mm, slab: release slab_mutex earlier in kmem_cache_destroy()	2012-10-10 09:25:08 +03:00
slob.c	Merge branch 'slab/tracing' into slab/for-linus	2012-10-03 09:57:17 +03:00
slub.c	Merge branch 'slab/common-for-cgroups' into slab/for-linus	2012-10-03 09:56:37 +03:00
sparse-vmemmap.c	mm: delete various needless include <linux/module.h>	2011-10-31 09:20:11 -04:00
sparse.c	mm/sparse: remove index_init_lock	2012-07-31 18:42:49 -07:00
swap.c	mm: remove vma arg from page_evictable	2012-10-09 16:22:55 +09:00
swap_state.c	mm: add support for a filesystem to activate swap files and use direct_IO for writing swap pages	2012-07-31 18:42:47 -07:00
swapfile.c	vfs: make path_openat take a struct filename pointer	2012-10-12 20:15:09 -04:00
truncate.c	mm: use clear_page_mlock() in page_remove_rmap()	2012-10-09 16:22:56 +09:00
util.c	mm: Use __do_krealloc to do the krealloc job	2012-09-04 10:22:58 +03:00
vmalloc.c	mm: use %pK for /proc/vmallocinfo	2012-10-09 16:23:03 +09:00
vmscan.c	CMA: migrate mlocked pages	2012-10-09 16:23:00 +09:00
vmstat.c	mm: remove unevictable_pgs_mlockfreed	2012-10-09 16:22:59 +09:00