Messages in this thread | | | Date | Fri, 10 Apr 2009 14:12:43 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH 1/2] lockdep: warn about lockdep disabling after kernel taint |
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* Frederic Weisbecker <fweisbec@gmail.com> wrote:
> Impact: provide useful missing info for developers > > Kernel taint can occur in several situations such as warnings, > load of prorietary or staging modules, bad page, etc... > > But when such taint happens, a developer might still be working on > the kernel, expecting that lockdep is still enabled. But a taint > disables lockdep without ever warning about it. > Such a kernel behaviour doesn't really help for kernel development. > > This patch adds this missing warning. > > Since the taint is done most of the time after the main message that > explain the real source issue, it seems safe to warn about it inside > add_taint() so that it appears at last, without hurting the main > information. > > Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> > > diff --git a/kernel/panic.c b/kernel/panic.c > index 3fd8c5b..9e7420a 100644 > --- a/kernel/panic.c > +++ b/kernel/panic.c > @@ -213,8 +213,14 @@ unsigned long get_taint(void) > > void add_taint(unsigned flag) > { > - /* can't trust the integrity of the kernel anymore: */ > - debug_locks = 0; > + /* > + * Can't trust the integrity of the kernel anymore. > + * We don't call directly debug_locks_off() because the issue > + * is not necessarily serious enough to set oops_in_progress to 1 > + */ > + if (xchg(&debug_locks, 0)) > + printk(KERN_WARNING "Disabling lockdep due to kernel taint\n"); > +
nice idea - but please use the proper debug_locks_off() construct instead of an open-coded xchg(). Something like:
if (debug_locks_off()) printk(...);
should do the trick.
Ingo
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