On Mon, 28 Apr 2014, Linus Torvalds wrote: > On Mon, Apr 28, 2014 at 2:20 PM, Linus Torvalds > <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > > > > That said, the bug does seem to be that some path doesn't invalidate > > the vmacache sufficiently, or something inserts a vmacache entry into > > the current process when looking up a remote process or whatever. > > Davidlohr, ideas? > > Maybe we missed some use_mm() call. That will change the current mm > without flushing the vma cache. The code considers kernel threads to > be bad targets for vma caching for this reason (and perhaps others), > but maybe we missed something. > > I wonder if we should just invalidate the vma cache in use_mm(), and > remote the "kernel tasks are special" check. > > Srivatsa, are you doing something peculiar on that system that would > trigger this? I see some kdump failures in the log, anything else? I doubt that the vmacache has anything to do with the real problem (though it *might* suggest that vmacache is less robust than what it replaced - maybe). The log is so full of userspace SIGSEGVs and General Protection faults, it looks like userspace was utterly broken by some kernel bug messing up the address space. Hugh -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>