On Wed, May 15, 2013 at 9:06 PM, Toralf Förster <toralf.foers...@gmx.de> wrote: > On 05/13/2013 09:12 AM, richard -rw- weinberger wrote: >> This looks like another issue. >> Are you testing process_vm_writev() with trinity? >> Looks like it managed to overwrite the stub page of a process, which >> is not good. > nope, it is the mremap syscall. > > A command like > > $>trinity -c mremap -N 10 > > immediately after starting a 32 bit Gentoo linux guest with current kernel > 3.10-rc1-... + > strnlen + stub4 patch works, but later a > > $>trinity -c mremap -N 1000 > > yields into > > 2013-05-15T21:02:04.061+02:00 trinity kernel: Stub registers - > 2013-05-15T21:02:04.061+02:00 trinity kernel: 0 - 100000 > 2013-05-15T21:02:04.061+02:00 trinity kernel: 1 - 300000 > 2013-05-15T21:02:04.061+02:00 trinity kernel: 2 - 0 > 2013-05-15T21:02:04.061+02:00 trinity kernel: 3 - 0 > 2013-05-15T21:02:04.061+02:00 trinity kernel: 4 - 0 > 2013-05-15T21:02:04.061+02:00 trinity kernel: 5 - 0 > 2013-05-15T21:02:04.061+02:00 trinity kernel: 6 - 0 > 2013-05-15T21:02:04.061+02:00 trinity kernel: 7 - 7b > 2013-05-15T21:02:04.061+02:00 trinity kernel: 8 - 7b > 2013-05-15T21:02:04.065+02:00 trinity kernel: 9 - 0 > 2013-05-15T21:02:04.065+02:00 trinity kernel: 10 - 33 > 2013-05-15T21:02:04.065+02:00 trinity kernel: 11 - ffffffff > 2013-05-15T21:02:04.065+02:00 trinity kernel: 12 - 1000c3 > 2013-05-15T21:02:04.065+02:00 trinity kernel: 13 - 73 > 2013-05-15T21:02:04.065+02:00 trinity kernel: 14 - 10206 > 2013-05-15T21:02:04.065+02:00 trinity kernel: 15 - 101028 > 2013-05-15T21:02:04.065+02:00 trinity kernel: 16 - 7b > 2013-05-15T21:02:04.065+02:00 trinity kernel: wait_stub_done : failed to wait > for SIGTRAP, pid = 15692, n = 15692, errno = 0, status = 0xb7f > > and now that process can't be killed - I had to stop the UML guest.
Hmm, you've remapped the stub page and therefore the process broke. I think it would make sense to kill the process in stead of writing the "wait_stub_done ..." message. Changing the stub page is as destructive than overwriting the stack. Maybe we can teach triniy to no change the stub page. I'm sure trinity has also a mechanism to not destroy the stack. -- Thanks, //richard ------------------------------------------------------------------------------ AlienVault Unified Security Management (USM) platform delivers complete security visibility with the essential security capabilities. Easily and efficiently configure, manage, and operate all of your security controls from a single console and one unified framework. Download a free trial. http://p.sf.net/sfu/alienvault_d2d _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel
