Re: NULL pointer dereference in the kernel 3.10

From: Willy Tarreau
Date: Mon Apr 10 2017 - 10:14:09 EST


On Mon, Apr 10, 2017 at 10:06:59PM +0800, zhong jiang wrote:
> On 2017/4/10 20:48, Michal Hocko wrote:
> > On Mon 10-04-17 20:10:06, zhong jiang wrote:
> >> On 2017/4/10 16:56, Mel Gorman wrote:
> >>> On Sat, Apr 08, 2017 at 09:39:42PM +0800, 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
> >>> Post the full report including the kernel version and state whether any
> >>> additional patches to 3.10 are applied.
> >>>
> >> Hi, Mel
> >>
> >> Our kernel from RHEL 7.2, Addtional patches all from upstream -- include Bugfix and CVE.
> > I believe you should contact Redhat for the support. This is a) old
> > kernel and b) with other patches which might or might not be relevant.
> Ok, regardless of the kernel version, we just discuss the situation in theory. if commit
> 624483f3ea8 ("mm: rmap: fix use-after-free in __put_anon_vma") is not exist. the issue
> will trigger . Any thought.

But this commit was backported into 3.10.43, so stable kernel users are safe.

Regards,
Willy