Messages in this thread | | | Date | Thu, 3 Oct 2019 21:39:28 +0200 | From | Christian Brauner <> | Subject | Re: Kernel Concurrency Sanitizer (KCSAN) |
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On Thu, Oct 03, 2019 at 06:00:38PM +0200, Dmitry Vyukov wrote: > On Thu, Oct 3, 2019 at 3:13 PM Dmitry Vyukov <dvyukov@google.com> wrote: > > > > On Wed, Oct 2, 2019 at 9:52 PM Marco Elver <elver@google.com> wrote: > > > > > > Hi Joel, > > > > > > On Tue, 1 Oct 2019 at 23:19, Joel Fernandes <joel@joelfernandes.org> wrote: > > > > > > > > On Fri, Sep 20, 2019 at 04:18:57PM +0200, Marco Elver wrote: > > > > > Hi all, > > > > > > > > > > We would like to share a new data-race detector for the Linux kernel: > > > > > Kernel Concurrency Sanitizer (KCSAN) -- > > > > > https://github.com/google/ktsan/wiki/KCSAN (Details: > > > > > https://github.com/google/ktsan/blob/kcsan/Documentation/dev-tools/kcsan.rst) > > > > > > > > > > To those of you who we mentioned at LPC that we're working on a > > > > > watchpoint-based KTSAN inspired by DataCollider [1], this is it (we > > > > > renamed it to KCSAN to avoid confusion with KTSAN). > > > > > [1] http://usenix.org/legacy/events/osdi10/tech/full_papers/Erickson.pdf > > > > > > > > > > In the coming weeks we're planning to: > > > > > * Set up a syzkaller instance. > > > > > * Share the dashboard so that you can see the races that are found. > > > > > * Attempt to send fixes for some races upstream (if you find that the > > > > > kcsan-with-fixes branch contains an important fix, please feel free to > > > > > point it out and we'll prioritize that). > > > > > > > > > > There are a few open questions: > > > > > * The big one: most of the reported races are due to unmarked > > > > > accesses; prioritization or pruning of races to focus initial efforts > > > > > to fix races might be required. Comments on how best to proceed are > > > > > welcome. We're aware that these are issues that have recently received > > > > > attention in the context of the LKMM > > > > > (https://lwn.net/Articles/793253/). > > > > > * How/when to upstream KCSAN? > > > > > > > > Looks exciting. I think based on our discussion at LPC, you mentioned > > > > one way of pruning is if the compiler generated different code with _ONCE > > > > annotations than what would have otherwise been generated. Is that still on > > > > the table, for the purposing of pruning the reports? > > > > > > This might be interesting at first, but it's not entirely clear how > > > feasible it is. It's also dangerous, because the real issue would be > > > ignored. It may be that one compiler version on a particular > > > architecture generates the same code, but any change in compiler or > > > architecture and this would no longer be true. Let me know if you have > > > any more ideas. > > > > > > Best, > > > -- Marco > > > > > > > Also appreciate a CC on future patches as well. > > > > > > > > thanks, > > > > > > > > - Joel > > > > > > > > > > > > > > > > > > Feel free to test and send feedback. > > > > FYI https://twitter.com/grsecurity/status/1179736828880048128 :) > > +Christian opts in for _all_ reports for > kernel/{fork,exit,pid,signal}.c and friends. > Just wanted it to be written down for future reference :)
Yes, please! :) Christian
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