Re: [RFC PATCH bpf-next v2 4/4] error-injection: Support fault injection framework

[Masami Hiramatsu]

On Tue, 26 Dec 2017 18:12:56 -0800
Alexei Starovoitov <alexei.starovoitov@xxxxxxxxx> wrote:

> On Tue, Dec 26, 2017 at 04:48:25PM +0900, Masami Hiramatsu wrote:
> > Support in-kernel fault-injection framework via debugfs.
> > This allows you to inject a conditional error to specified
> > function using debugfs interfaces.
> > 
> > Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> > ---
> >  Documentation/fault-injection/fault-injection.txt |    5 +
> >  kernel/Makefile                                   |    1 
> >  kernel/fail_function.c                            |  169 +++++++++++++++++++++
> >  lib/Kconfig.debug                                 |   10 +
> >  4 files changed, 185 insertions(+)
> >  create mode 100644 kernel/fail_function.c
> > 
> > diff --git a/Documentation/fault-injection/fault-injection.txt b/Documentation/fault-injection/fault-injection.txt
> > index 918972babcd8..6243a588dd71 100644
> > --- a/Documentation/fault-injection/fault-injection.txt
> > +++ b/Documentation/fault-injection/fault-injection.txt
> > @@ -30,6 +30,11 @@ o fail_mmc_request
> >    injects MMC data errors on devices permitted by setting
> >    debugfs entries under /sys/kernel/debug/mmc0/fail_mmc_request
> >  
> > +o fail_function
> > +
> > +  injects error return on specific functions by setting debugfs entries
> > +  under /sys/kernel/debug/fail_function. No boot option supported.
> 
> I like it.
> Could you document it a bit better?

Yes, I will do in next series.

> In particular retval is configurable, but without an example no one
> will be able to figure out how to use it.

Ah, right. BTW, as I pointed in the covermail, should we store the
expected error value range into the injectable list? e.g.

ALLOW_ERROR_INJECTION(open_ctree, -1, -MAX_ERRNO)

And provide APIs to check/get it.

const struct error_range *ei_get_error_range(unsigned long addr);


> 
> I think you can drop RFC tag from the next version of these patches.
> Thanks!

Thank you, I'll fix some errors came from configurations, and resend it.


Thanks!


-- 
Masami Hiramatsu <mhiramat@xxxxxxxxxx>