On 3/20/20 9:26 AM, Paul E. McKenney wrote: > On Fri, Mar 20, 2020 at 04:38:54PM +0100, Dmitry Vyukov wrote: >> On Thu, Mar 19, 2020 at 4:04 PM Paul E. McKenney <paulmck@xxxxxxxxxx> wrote: >>> >>> On Thu, Mar 19, 2020 at 08:13:35AM +0100, Dmitry Vyukov wrote: >>>> On Wed, Mar 18, 2020 at 10:41 PM Paul E. McKenney <paulmck@xxxxxxxxxx> wrote: >>>>> >>>>> On Wed, Mar 18, 2020 at 09:54:07PM +0100, Dmitry Vyukov wrote: >>>>>> On Wed, Mar 18, 2020 at 5:57 PM syzbot >>>>>> <syzbot+792dec47d693ccdc05a0@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: >>>>>>> >>>>>>> Hello, >>>>>>> >>>>>>> syzbot found the following crash on: >>>>>>> >>>>>>> HEAD commit: 47780d78 Add linux-next specific files for 20200318 >>>>>>> git tree: linux-next >>>>>>> console output: https://syzkaller.appspot.com/x/log.txt?x=14228745e00000 >>>>>>> kernel config: https://syzkaller.appspot.com/x/.config?x=b68b7b89ad96c62a >>>>>>> dashboard link: https://syzkaller.appspot.com/bug?extid=792dec47d693ccdc05a0 >>>>>>> compiler: gcc (GCC) 9.0.0 20181231 (experimental) >>>>>>> >>>>>>> Unfortunately, I don't have any reproducer for this crash yet. >>>>>>> >>>>>>> IMPORTANT: if you fix the bug, please add the following tag to the commit: >>>>>>> Reported-by: syzbot+792dec47d693ccdc05a0@xxxxxxxxxxxxxxxxxxxxxxxxx >>>>>>> >>>>>>> kernel/rcu/tasks.h:1070:37: error: 'rcu_tasks_rude' undeclared (first use in this function); did you mean 'rcu_tasks_qs'? >>>>>> >>>>>> +rcu maintainers >>>>> >>>>> The kbuild test robot beat you to it, and apologies for the hassle. >>>>> Fixed in -rcu on current "dev" branch. >>>> >>>> If the kernel dev process would only have a way to avoid dups from all >>>> test systems... >>> >>> I do significant testing before pushing to -next, but triggering this >>> one requires a combination of Kconfig options that are incompatible >>> with rcutorture. :-/ >>> >>> I suppose one strategy would be to give kbuild test robot some time before >>> passing to -next, but they seem to sometimes get too far behind for me to >>> be willing to wait that long. So my current approach is to push my "dev" >>> branch, run moderate rcutorture testing (three hours per scenario other >>> than TREE10, which gets only one hour), and if that passes, push to -next. >>> >>> I suppose that I could push to -next only commits that are at least three >>> days old or some such. But I get in trouble pushing to -next too slowly >>> as often as I get in trouble pushing too quickly, so I suspect that my >>> current approach is in roughly the right place. >>> >>>> Now we need to spend time and deal with it. What has fixed it? >>> >>> It is fixed by commit c6ef38e4d595 ("rcu-tasks: Add RCU tasks to >>> rcutorture writer stall output") and some of its predecessors. >>> >>> Perhaps more useful to you, this commit is included in next-20200319 >>> from the -next tree. ;-) >> >> Let's tell syzbot about the fix: >> >> #syz fix: rcu-tasks: Add RCU tasks to rcutorture writer stall output >> >> I think what you are doing is the best possible option in the current situation. >> I don't think requiring all human maintainers to do more manual >> repetitive work, which is not well defined and even without a way to >> really require something from them is scalable nor reliable nor the >> right approach. > > Thank you, and I do greatly appreciate the automation! > >> We would consume something like LKGR [1] if it existed for the kernel. >> But it would require tighter integration of testing systems with >> kernel dev processes, or of course throwing more manual labor at it to >> track all uncoordinated testing systems and publishing LKGR tags. >> >> [1] https://chromium.googlesource.com/chromiumos/docs/+/master/glossary.md > > At my end, it is pretty quick and easy to detect duplicate notifications > of the same bug, so the current situation isn't causing me undue distress. Yeah, I saw the same build error and did-not-report it since it was already reported. :) -- ~Randy
