On Fri, Jan 22, 2016 at 12:33:24PM +0800, kernel test robot wrote: > Greetings, > > 0day kernel testing robot got the below dmesg and the first bad commit is > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master > > commit 75925e1ad7f5a4e867bd14ff8e7f114ea1596434 > Author: Andi Kleen <a...@linux.intel.com> > AuthorDate: Thu Oct 22 15:07:21 2015 -0700 > Commit: Ingo Molnar <mi...@kernel.org> > CommitDate: Mon Nov 23 09:58:25 2015 +0100 > > perf/x86: Optimize stack walk user accesses > > Change the perf user stack walking to use the new > __copy_from_user_nmi(), and split each access into word sized transfer > sizes. This allows to inline the complete access and optimize it all > into a single load.
Andi, please have a look at this. Also note that x86_64 __copy_from_user_nocheck() actually supports .size=16.
