lkml.org 
[lkml]   [2012]   [Apr]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] Prevent crash on missing sysfs attribute group

* Eric W. Biederman <ebiederm@xmission.com> wrote:

> Ingo Molnar <mingo@kernel.org> writes:
>
> > * Eric W. Biederman <ebiederm@xmission.com> wrote:
> >
> >> > Huh, so put repeated, duplicated, inconsistently applied sanity
> >> > checks into dozens of sysfs attribute using kernel subsystems?
> >>
> >> [...]
> >>
> >> No. I was not talking about every usage site.
> >
> > Note, I'm not arguing that this isn't a bug in the P4 PMU driver
> > - it is clearly a bug and I've applied the fix for it. I'm
> > arguing about the escallation vector that this bug takes - that
> > is unnecessarily disruptive:
> >
> > You were talking about:
> >
> >> >> FIX perf to include sanity checks.
> >
> > and what the PMU drivers do here is not uncommon at all, and the
> > bug (for which I applied the fix and will push to Linus ASAP) is
> > not uncommon either:
>
> > Bugs happen and indirections happen too. perf uses a generic
> > PMU driver layer where the lower level layers register
> > themselves. There's at least a dozen similar constructs in
> > the kernel and you suggest that the right solution is to put
> > checks in every one of them, while the nice patch from Bruno
> > could catch it too, in one central place?
>
> What is uncommon is that perf_pmu_register is called from an
> early initcall, and then later a device_init call is used to
> register the pmu subsystem with sysfs.

This has no relevance to the bug and crash pattern itself
whatsoever, so stop blathering about unrelated things.

Not filling out a sysfs object attribute is an *easy* driver
level mistake, I've seen it happen on numerous occasions. Not
crashing on it in the sysfs layer is an *obvious* debugging
helper, and I don't understand why you are even arguing about
this.

Thanks,

Ingo


\
 
 \ /
  Last update: 2012-04-03 12:19    [W:0.104 / U:0.084 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site