Messages in this thread | | | Date | Sat, 11 Apr 2009 03:37:54 +0200 | From | Frederic Weisbecker <> | Subject | Re: [PATCH 2/2] lockdep: choose to continue lock debugging despite taint |
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On Sat, Apr 11, 2009 at 03:15:06AM +0200, Frederic Weisbecker wrote: > On Fri, Apr 10, 2009 at 03:45:20PM +0200, Ingo Molnar wrote: > > > > * Frederic Weisbecker <fweisbec@gmail.com> wrote: > > > > > On Fri, Apr 10, 2009 at 02:15:15PM +0200, Ingo Molnar wrote: > > > > > > > > * Frederic Weisbecker <fweisbec@gmail.com> wrote: > > > > > > > > > Lockdep is disabled after any kernel taints. This might be > > > > > convenient to ignore bad locking issues which sources come from > > > > > outside the kernel tree. Nevertheless, it might be a frustrating > > > > > experience for the staging developers or anyone who might develop > > > > > a kernel that happens to be tainted. > > > > > > > > Good point. Not having lockdep coverage for drivers/staging/ just > > > > prolongs their transition - not good. > > > > > > > > But instead of this: > > > > > > > > > void add_taint(unsigned flag) > > > > > { > > > > > +#ifndef CONFIG_LOCKDEP_IGNORE_TAINT > > > > > /* > > > > > * Can't trust the integrity of the kernel anymore. > > > > > * We don't call directly debug_locks_off() because the issue > > > > > @@ -220,6 +221,7 @@ void add_taint(unsigned flag) > > > > > */ > > > > > if (xchg(&debug_locks, 0)) > > > > > printk(KERN_WARNING "Disabling lockdep due to kernel taint\n"); > > > > > +#endif > > > > > > > > I'd suggest to not do the debug_locks_off() call if TAINT_CRAP. I.e. > > > > something like: > > > > > > > > if (!(flag & TAINT_CRAP) && debug_locks_off()) > > > > printk(...); > > > > > > > > will do the trick. > > > > > > > > Ingo > > > > > > > > > Ok, but this is not only about staging. It's also about > > > TAINT_WARN. Just imagine that you report a warning to a > > > maintainer, and while you are waiting for it to be fixed, you > > > can't use lockdep for your own needs. > > > > > > Hm? > > > > We can exclude TAINT_WARN too - i.e. (TAINT_CRAP|TAINT_WARN). > > > > Ingo > > > Fine :-) > > See the v2 on further mails in this thread. > > Side request: do you think you could merge them on kill-the-BKL tree?
Sorry, forget about this side request. I thought merging tip:master into tip:core/kill-the-BKL would make me suffer a rain of conflicts but actually I've just tried and I only encountered a very simple conflict in sched.c so it's very easy to manage it locally. Then we can keep the history of kill-the-BKL, for now it's good as is.
Frederic.
> Thanks! >
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