On Wed, May 15, 2013 at 9:35 PM, richard -rw- weinberger <richard.weinberger@xxxxxxxxx> wrote: > On Wed, May 15, 2013 at 9:30 PM, Toralf Förster <toralf.foerster@xxxxxx> wrote: >> On 05/15/2013 09:11 PM, richard -rw- weinberger wrote: >>> On Wed, May 15, 2013 at 9:06 PM, Toralf Förster <toralf.foerster@xxxxxx> 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. >> >> Unfortunately no trinity process can be killed as soon as that happen. >> Neither pgrep, pkill, nor "ps -efla" do return any result. >> Killing any of those processes by its pid won't work too. > > Hmm, not good. > I need to create me a reproducer for that. > I'm unsure what exactly is going on. Good news, I have a reproducer for the problem and found out what the root cause is. UML is unable to terminate the task with the broken skas page. A fix is on the way... -- Thanks, //richard -- To unsubscribe from this list: send the line "unsubscribe trinity" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
