On Tue, Dec 19, 2017 at 12:27:30PM -0600, Eric W. Biederman wrote: > Dave Jones <da...@codemonkey.org.uk> writes: > > > On Mon, Dec 18, 2017 at 03:50:52PM -0800, Linus Torvalds wrote: > > > > > But I don't see what would have changed in this area recently. > > > > > > Do you end up saving the seeds that cause crashes? Is this > > > reproducible? (Other than seeing it twoce, of course) > > > > Only clue so far, is every time I'm able to trigger it, the last thing > > the child process that triggers it did, was an execveat. > > Is there any chance the excveat might be called from a child thread?
If trinity choose one of the exec syscalls, it forks off an extra child to do it in, on the off-chance that it succeeds, and we never return. https://github.com/kernelslacker/trinity/blob/master/syscall.c#L139 > That switching pids between tasks of a process during exec can get a > little bit tricky. > > > Telling it to just fuzz execveat doesn't instantly trigger it, so it > > must be a combination of some other syscall. I'll leave a script running > > overnight to see if I can binary search the other syscalls in > > combination with it. > > Could we have a buggy syscall that is stomping something? Not totally impossible I guess, though I would expect that would manifest in additional random failures, whereas this seems remarkably consistent. Dave
