Re: 4.7-rc7: use-after-free in proc_map_files_readdir

[Dave Jones <davej@codemonkey.org.uk>]

On Tue, Jul 19, 2016 at 08:38:57PM +0100, Al Viro wrote:
 > On Tue, Jul 19, 2016 at 02:33:27PM -0400, Dave Jones wrote:
 > >  > Could you dump the relevant part of vmlinux objdump, rather than whatever
 > >  > you've used on base.o?  Having relocations resolved makes it much easier
 > >  > to figure out...  Or just dump that vmlinux on anonftp somewhere...
 > > 
 > > http://codemonkey.org.uk/junk/vmlinux.gz
 > 
 > OK, it's actually about fetching ->f_mode in
 >                         info.mode = vma->vm_file->f_mode;
 > 
 > %r15 points contains vma->vm_file at that point, and 0x84 is the offset of
 > f_mode in struct file on your config from hell (due to spinlock_t size
 > exploding on lockdep et.al.)
 > 
 > Interesting...  Do you have a reproducer for that?

Will give it another run when I get home. Machine is locked up for unknown
reasons right now..

	Dave