kernel-ark/mm
Vegard Nossum cbb766766f mm: fix lazy vmap purging (use-after-free error)
I just got this new warning from kmemcheck:

    WARNING: kmemcheck: Caught 32-bit read from freed memory (c7806a60)
    a06a80c7ecde70c1a04080c700000000a06709c1000000000000000000000000
     f f f f f f f f f f f f f f f f f f f f f f f f f f f f f f f f
     ^

    Pid: 0, comm: swapper Not tainted (2.6.29-rc4 #230)
    EIP: 0060:[<c1096df7>] EFLAGS: 00000286 CPU: 0
    EIP is at __purge_vmap_area_lazy+0x117/0x140
    EAX: 00070f43 EBX: c7806a40 ECX: c1677080 EDX: 00027b66
    ESI: 00002001 EDI: c170df0c EBP: c170df00 ESP: c178830c
     DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
    CR0: 80050033 CR2: c7806b14 CR3: 01775000 CR4: 00000690
    DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
    DR6: 00004000 DR7: 00000000
     [<c1096f3e>] free_unmap_vmap_area_noflush+0x6e/0x70
     [<c1096f6a>] remove_vm_area+0x2a/0x70
     [<c1097025>] __vunmap+0x45/0xe0
     [<c10970de>] vunmap+0x1e/0x30
     [<c1008ba5>] text_poke+0x95/0x150
     [<c1008ca9>] alternatives_smp_unlock+0x49/0x60
     [<c171ef47>] alternative_instructions+0x11b/0x124
     [<c171f991>] check_bugs+0xbd/0xdc
     [<c17148c5>] start_kernel+0x2ed/0x360
     [<c171409e>] __init_begin+0x9e/0xa9
     [<ffffffff>] 0xffffffff

It happened here:

    $ addr2line -e vmlinux -i c1096df7
    mm/vmalloc.c:540

Code:

	list_for_each_entry(va, &valist, purge_list)
		__free_vmap_area(va);

It's this instruction:

    mov    0x20(%ebx),%edx

Which corresponds to a dereference of va->purge_list.next:

    (gdb) p ((struct vmap_area *) 0)->purge_list.next
    Cannot access memory at address 0x20

It seems that we should use "safe" list traversal here, as the element
is freed inside the loop. Please verify that this is the right fix.

Acked-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: <stable@kernel.org>		[2.6.28.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-27 16:26:21 -08:00
..
allocpercpu.c
backing-dev.c Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-01-06 17:10:04 -08:00
bootmem.c bootmem: print request details before BUG_ON(them) 2009-01-06 15:59:10 -08:00
bounce.c bounce: don't rely on a zeroed bio_vec list 2008-12-29 08:29:52 +01:00
dmapool.c
fadvise.c [CVE-2009-0029] System call wrapper special cases 2009-01-14 14:15:18 +01:00
failslab.c SLUB: failslab support 2008-12-29 11:27:46 +02:00
filemap_xip.c badpage: remove vma from page_remove_rmap 2009-01-06 15:59:07 -08:00
filemap.c [CVE-2009-0029] System call wrapper special cases 2009-01-14 14:15:18 +01:00
fremap.c Do not account for the address space used by hugetlbfs using VM_ACCOUNT 2009-02-10 10:48:42 -08:00
highmem.c
hugetlb.c Do not account for hugetlbfs quota at mmap() time if mapping [SHM|MAP]_NORESERVE 2009-02-11 12:38:09 -08:00
internal.h mm: make get_user_pages() interruptible 2009-01-06 15:59:08 -08:00
Kconfig Remove obsolete CONFIG_RESOURCES_64BIT 2009-01-06 15:59:14 -08:00
maccess.c
madvise.c [CVE-2009-0029] System call wrappers part 14 2009-01-14 14:15:24 +01:00
Makefile shmem: unify regular and tiny shmem 2009-01-06 15:59:08 -08:00
memcontrol.c memcg: NULL pointer dereference at rmdir on some NUMA systems 2009-01-29 18:04:44 -08:00
memory_hotplug.c mm: remove GFP_HIGHUSER_PAGECACHE 2009-01-06 15:59:01 -08:00
memory.c do_wp_page: fix regression with execute in place 2009-02-05 12:56:48 -08:00
mempolicy.c [CVE-2009-0029] System call wrappers part 28 2009-01-14 14:15:30 +01:00
mempool.c
migrate.c migration: migrate_vmas should check "vma" 2009-02-11 14:25:34 -08:00
mincore.c [CVE-2009-0029] System call wrappers part 14 2009-01-14 14:15:24 +01:00
mlock.c Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-02-17 14:27:39 -08:00
mm_init.c
mmap.c mm: rearrange exit_mmap() to unlock before arch_exit_mmap 2009-02-11 14:25:37 -08:00
mmu_notifier.c
mmzone.c
mprotect.c Do not account for the address space used by hugetlbfs using VM_ACCOUNT 2009-02-10 10:48:42 -08:00
mremap.c [CVE-2009-0029] System call wrappers part 13 2009-01-14 14:15:23 +01:00
msync.c [CVE-2009-0029] System call wrappers part 13 2009-01-14 14:15:23 +01:00
nommu.c uclinux: add process name to allocation error message 2009-01-27 16:42:03 +10:00
oom_kill.c memcg: avoid deadlock caused by race between oom and cpuset_attach 2009-01-08 08:31:09 -08:00
page_alloc.c mm: fix memmap init for handling memory hole 2009-02-18 15:37:55 -08:00
page_cgroup.c memcg: use __GFP_NOWARN in page cgroup allocation 2009-02-11 14:25:35 -08:00
page_io.c block: fix bad definition of BIO_RW_SYNC 2009-02-18 10:32:00 +01:00
page_isolation.c
page-writeback.c mm: task dirty accounting fix 2009-02-18 15:37:54 -08:00
pagewalk.c
pdflush.c cpumask: convert mm/ 2009-01-01 10:12:29 +10:30
prio_tree.c
quicklist.c
readahead.c
rmap.c mm: fix mlocked page counter mismatch 2009-02-11 14:25:35 -08:00
shmem_acl.c
shmem.c shmem: fix shared anonymous accounting 2009-02-25 12:21:42 -08:00
slab.c mm: Export symbol ksize() 2009-02-12 17:50:46 +02:00
slob.c mm: Export symbol ksize() 2009-02-12 17:50:46 +02:00
slub.c mm: Export symbol ksize() 2009-02-12 17:50:46 +02:00
sparse-vmemmap.c
sparse.c meminit section warnings 2008-11-30 10:03:35 -08:00
swap_state.c memcg: mem+swap controller core 2009-01-08 08:31:05 -08:00
swap.c memcg: add zone_reclaim_stat 2009-01-08 08:31:08 -08:00
swapfile.c PM/hibernate: fix "swap breaks after hibernation failures" 2009-02-21 14:17:17 -08:00
thrash.c
truncate.c
util.c slab: introduce kzfree() 2009-02-20 17:57:48 -08:00
vmalloc.c mm: fix lazy vmap purging (use-after-free error) 2009-02-27 16:26:21 -08:00
vmscan.c swsusp: clean up shrink_all_zones() 2009-02-21 14:17:17 -08:00
vmstat.c cpumask: convert mm/ 2009-01-01 10:12:29 +10:30