Hi Dmitry, On Tue, Mar 12, 2019 at 09:21:09AM +0100, 'Dmitry Vyukov' via syzkaller-bugs wrote: > On Tue, Mar 12, 2019 at 7:43 AM Eric Biggers <ebigg...@kernel.org> wrote: > > > > On Mon, Mar 11, 2019 at 11:25:41PM -0700, Andrew Morton wrote: > > > On Tue, 12 Mar 2019 07:08:38 +0100 Dmitry Vyukov <dvyu...@google.com> > > > wrote: > > > > > > > On Tue, Mar 12, 2019 at 12:37 AM Andrew Morton > > > > <a...@linux-foundation.org> wrote: > > > > > > > > > > On Mon, 11 Mar 2019 06:08:01 -0700 syzbot > > > > > <syzbot+fa11f9da42b46cea3...@syzkaller.appspotmail.com> wrote: > > > > > > > > > > > syzbot has bisected this bug to: > > > > > > > > > > > > commit 29a4b8e275d1f10c51c7891362877ef6cffae9e7 > > > > > > Author: Shakeel Butt <shake...@google.com> > > > > > > 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+fa11f9da42b46cea3...@syzkaller.appspotmail.com > > > > > > 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? > > Hi Eric, > > This bug was reported on Jan 10: > https://syzkaller.appspot.com/bug?extid=fa11f9da42b46cea3b4a > https://groups.google.com/forum/#!msg/syzkaller-bugs/5YkhNUg2PFY/4-B5M7bDCAAJ > > The start revision of the bisection process (provided) is the same > that was used to create the reproducer. The end revision and bisection > log are provided in the email. > > How can we improve the format to make it more clear? >
syzbot started a new thread rather than sending the bisection result in the existing thread. So I thought it was a new bug report, as did everyone else probably. - Eric
