On Sun, Nov 25, 2018 at 6:31 PM Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: > > On 20/11/18 09:34, Wanpeng Li wrote: > > From: Wanpeng Li <wanpengli@xxxxxxxxxxx> > > ... > > This patch fixes it by bailing out scan ioapic if ioapic is not initialized in > > kernel. > > Reported-by: Wei Wu <ww9210@xxxxxxxxx> +Linus, Greg I want to point out that this was reported more then 3 months ago by syzbot: https://groups.google.com/forum/#!msg/syzkaller-bugs/cPT7tmaz-gQ/SzOyhM0YBAAJ then the report was lost on kernel mailing lists and then re-reported by somebody else: https://www.spinics.net/lists/kvm/msg177705.html and only then fixed. Lots of kernel bug reports routinely get lost on mailing lists, which is bad. Another bug was reported by syzbot in April: https://groups.google.com/forum/#!msg/syzkaller-bugs/-9XIT9gwq7M/sqvBXSZWBgAJ then get lost and then re-reported in November: https://www.spinics.net/lists/kvm/msg177704.html and only then fixed. Not specific for KVM, another bug in kernel/trace reported by syzbot, lost for months, then re-reported and fixed: https://groups.google.com/forum/#!msg/syzkaller-bugs/o_-OeMyoTwg/Ugh432hlAgAJ https://bugzilla.kernel.org/show_bug.cgi?id=200019 And, no, it's not that people ignore just syzbot reports. It's just that syzbot reports can be tracked so it's easier to spot such cases, for manually reported bugs nobody usually knows anything after few weeks. Here is an example of bug report by a human, which was even replied but then slipped from somebody's attention set for a moment and then complete oblivion. Months later happened to be re-reported by syzbot and then fixed: https://groups.google.com/forum/#!msg/syzkaller-bugs/wFUedfOK2Rw/waUrQYOxAQAJ Re-reported a year later bugs can cause security problems and large amounts of work to backport the fix to thousands of downstream kernel forks. Not re-reported bugs are even worse as they are just not fixed. This Plumbers I was approached by Doug Ledford from Redhat, who said literally that there was a bunch of syzbot reports in rdma subsystem but since they were reported some time ago, now nobody knows what/where are they. So while the bugs are still presumably there, now they are completely unactionable and kernel development process is incapable of dealing with this. While syzbot reports have some chances of being recovered, this equally applies to human-reported bugs and they can't be easily recovered. This does not looks like how things should be for the most critical and fundamental software project in the world. Lost bugs/patches should not be a thing. There are known working solutions for this in the form of tooling and procedures, namely bug tracking. Any bug tracking systems allows to answer the main question: what are the active bugs, sorted by priority, in subsystem X/assigned to me; and lots of other useful questions. And, yes, I know we have bugazilla. But it's not being used as a bug tracking system as of now. And when used, sometimes cause more trouble because nobody expects bugs to be there: https://lwn.net/ml/linux-kernel/20181208115629.GA3288@xxxxxxxxx/
