On April 10, 2017 4:57 PM Xishi Qiu wrote:
> On 2017/4/10 14:42, Hillf Danton wrote:
>
> > On April 08, 2017 9:40 PM zhong Jiang wrote:
> >>
> >> when runing the stabile docker cases in the vm. The following issue will come up.
> >>
> >> #40 [ffff8801b57ffb30] async_page_fault at ffffffff8165c9f8
> >> [exception RIP: down_read_trylock+5]
> >> RIP: ffffffff810aca65 RSP: ffff8801b57ffbe8 RFLAGS: 00010202
> >> RAX: 0000000000000000 RBX: ffff88018ae858c1 RCX: 0000000000000000
> >> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000008
> >> RBP: ffff8801b57ffc10 R8: ffffea0006903de0 R9: ffff8800b3c61810
> >> R10: 00000000000022cb R11: 0000000000000000 R12: ffff88018ae858c0
> >> R13: ffffea0006903dc0 R14: 0000000000000008 R15: ffffea0006903dc0
> >> ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0000
> >> #41 [ffff8801b57ffbe8] page_lock_anon_vma_read at ffffffff811b241c
> >> #42 [ffff8801b57ffc18] page_referenced at ffffffff811b26a7
> >> #43 [ffff8801b57ffc90] shrink_active_list at ffffffff8118d634
> >> #44 [ffff8801b57ffd48] balance_pgdat at ffffffff8118f088
> >> #45 [ffff8801b57ffe20] kswapd at ffffffff8118f633
> >> #46 [ffff8801b57ffec8] kthread at ffffffff810a795f
> >> #47 [ffff8801b57fff50] ret_from_fork at ffffffff81665398
> >> crash> struct page.mapping ffffea0006903dc0
> >> mapping = 0xffff88018ae858c1
> >> crash> struct anon_vma 0xffff88018ae858c0
> >> struct anon_vma {
> >> root = 0x0,
> >> rwsem = {
> >> count = 0,
> >> wait_lock = {
> >> raw_lock = {
> >> {
> >> head_tail = 1,
> >> tickets = {
> >> head = 1,
> >> tail = 0
> >> }
> >> }
> >> }
> >> },
> >> wait_list = {
> >> next = 0x0,
> >> prev = 0x0
> >> }
> >> },
> >> refcount = {
> >> counter = 0
> >> },
> >> rb_root = {
> >> rb_node = 0x0
> >> }
> >> }
> >>
> >> This maks me wonder, the anon_vma do not come from slab structure.
> >> and the content is abnormal. IMO, At least anon_vma->root will not NULL.
> >> The issue can be reproduced every other week.
> >>
> > Check please if commit
> > 624483f3ea8 ("mm: rmap: fix use-after-free in __put_anon_vma")
> > is included in the 3.10 you are running.
> >
> We missed this patch in RHEL 7.2
> Could you please give more details for how it triggered?
Sorry, I could not.
I guess it is UAF as described in the log of that commit.
And if it works for you, we know how.
Hillf
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