Re: [PATCH v8 1/4] fs/proc/kcore: avoid bounce buffer for ktext data

Jiri Olsa
2023-07-24T08:18:57Z

On Mon, Jul 24, 2023 at 04:08:41PM +0800, Baoquan He wrote:
> On 07/24/23 at 08:23am, David Hildenbrand wrote:
> > Hi,
> >
> > >
> > > I met this too when I executed below command to trigger a kcore reading.
> > > I wanted to do a simple testing during system running and got this.
> > >
> > > makedumpfile --mem-usage /proc/kcore
> > >
> > > Later I tried your above objdump testing, it corrupted system too.
> > >
> >
> > What do you mean with "corrupted system too" -- did it not only fail to
> > dump the system, but also actually harmed the system?
>
> From my testing, reading kcore will cause system panic, then reboot. Not
> sure if Jiri saw the same phenomenon.

it did not crash for me, just the read error
could you get console output from that?

jirka

>
> >
> > @Lorenzo do you plan on reproduce + fix, or should we consider reverting
> > that change?
>
> When tested on a arm64 system, the reproducution is stable. I will have
> a look too to see if I have some finding this week.
>