On Mon, Mar 11, 2019 at 11:25:41PM -0700, Andrew Morton wrote: > On Tue, 12 Mar 2019 07:08:38 +0100 Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote: > > > On Tue, Mar 12, 2019 at 12:37 AM Andrew Morton > > <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > > > > > > On Mon, 11 Mar 2019 06:08:01 -0700 syzbot <syzbot+fa11f9da42b46cea3b4a@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > > > > > > syzbot has bisected this bug to: > > > > > > > > commit 29a4b8e275d1f10c51c7891362877ef6cffae9e7 > > > > Author: Shakeel Butt <shakeelb@xxxxxxxxxx> > > > > Date: Wed Jan 9 22:02:21 2019 +0000 > > > > > > > > memcg: schedule high reclaim for remote memcgs on high_work > > > > > > > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=155bf5db200000 > > > > start commit: 29a4b8e2 memcg: schedule high reclaim for remote memcgs on.. > > > > git tree: linux-next > > > > final crash: https://syzkaller.appspot.com/x/report.txt?x=175bf5db200000 > > > > console output: https://syzkaller.appspot.com/x/log.txt?x=135bf5db200000 > > > > kernel config: https://syzkaller.appspot.com/x/.config?x=611f89e5b6868db > > > > dashboard link: https://syzkaller.appspot.com/bug?extid=fa11f9da42b46cea3b4a > > > > userspace arch: amd64 > > > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14259017400000 > > > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=141630a0c00000 > > > > > > > > Reported-by: syzbot+fa11f9da42b46cea3b4a@xxxxxxxxxxxxxxxxxxxxxxxxx > > > > Fixes: 29a4b8e2 ("memcg: schedule high reclaim for remote memcgs on > > > > high_work") > > > > > > The following patch > > > memcg-schedule-high-reclaim-for-remote-memcgs-on-high_work-v3.patch > > > might have fixed this. Was it applied? > > > > Hi Andrew, > > > > You mean if the patch was applied during the bisection? > > No, it wasn't. Bisection is very specifically done on the same tree > > where the bug was hit. There are already too many factors that make > > the result flaky/wrong/inconclusive without changing the tree state. > > Now, if syzbot would know about any pending fix for this bug, then it > > would not do the bisection at all. But it have not seen any patch in > > upstream/linux-next with the Reported-by tag, nor it received any syz > > fix commands for this bugs. Should have been it aware of the fix? How? > > memcg-schedule-high-reclaim-for-remote-memcgs-on-high_work-v3.patch was > added to linux-next on Jan 10. I take it that this bug was hit when > testing the entire linux-next tree, so we can assume that > memcg-schedule-high-reclaim-for-remote-memcgs-on-high_work-v3.patch > does not fix it, correct? > > In which case, over to Shakeel! > I don't understand what happened here. First, the syzbot report doesn't say which linux-next version was tested (which it should), but I get: $ git tag --contains 29a4b8e275d1f10c51c7891362877ef6cffae9e7 next-20190110 next-20190111 next-20190114 next-20190115 next-20190116 That's almost 2 months old, yet this bug was just reported now. Why? - Eric
