Messages in this thread | | | Date | Mon, 4 Jan 2021 10:14:02 +0000 | From | Mark Rutland <> | Subject | Re: [PATCH] lockdep: report broken irq restoration |
| |
On Thu, Dec 17, 2020 at 03:36:40PM +0100, Peter Zijlstra wrote: > On Wed, Dec 09, 2020 at 06:33:37PM +0000, Mark Rutland wrote: > > This means that a seuence such as: > > +q > > > diff --git a/include/linux/irqflags.h b/include/linux/irqflags.h > > index 3ed4e8771b64..bca3c6fa8270 100644 > > --- a/include/linux/irqflags.h > > +++ b/include/linux/irqflags.h > > @@ -220,10 +220,26 @@ do { \ > > > > #else /* !CONFIG_TRACE_IRQFLAGS */ > > > > +#ifdef CONFIG_DEBUG_IRQFLAGS > > +extern void warn_bogus_irq_restore(bool *warned); > > +#define check_bogus_irq_restore() \ > > + do { \ > > + static bool __section(".data.once") __warned; \ > > + if (unlikely(!raw_irqs_disabled())) \ > > + warn_bogus_irq_restore(&__warned); \ > > + } while (0) > > +#else > > +#define check_bogus_irq_restore() do { } while (0) > > +#endif > > + > > #define local_irq_enable() do { raw_local_irq_enable(); } while (0) > > #define local_irq_disable() do { raw_local_irq_disable(); } while (0) > > #define local_irq_save(flags) do { raw_local_irq_save(flags); } while (0) > > -#define local_irq_restore(flags) do { raw_local_irq_restore(flags); } while (0) > > +#define local_irq_restore(flags) \ > > + do { \ > > + check_bogus_irq_restore(); \ > > + raw_local_irq_restore(flags); \ > > + } while (0) > > Shouldn't that be in raw_local_irq_restore() ?
Yup, that'd be preferable. Note that will require a refactoring here if we want the warning to be available regardless of CONFIG_TRACE_IRQFLAGS.
I'd intended to rejig that for v2, but I didn't get the chance before finishing work for the year, and had only done some basic rework in my WIP (e.g. removing the per-instance bool as per Andy's comments):
https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/commit/?h=fuzzing/5.10-rc7&id=61336e25d1415a4ac3aaf8cf75105c2ec2eb95e7
I'll try to respin that in the next few days if I get the chance.
Thanks, Mark.
> > > #define safe_halt() do { raw_safe_halt(); } while (0) > > > > #endif /* CONFIG_TRACE_IRQFLAGS */ > > --- a/include/linux/irqflags.h > +++ b/include/linux/irqflags.h > @@ -162,6 +162,7 @@ do { \ > #define raw_local_irq_restore(flags) \ > do { \ > typecheck(unsigned long, flags); \ > + check_bogus_irq_restore(); \ > arch_local_irq_restore(flags); \ > } while (0) > #define raw_local_save_flags(flags) \ > @@ -235,11 +236,7 @@ extern void warn_bogus_irq_restore(bool > #define local_irq_enable() do { raw_local_irq_enable(); } while (0) > #define local_irq_disable() do { raw_local_irq_disable(); } while (0) > #define local_irq_save(flags) do { raw_local_irq_save(flags); } while (0) > -#define local_irq_restore(flags) \ > - do { \ > - check_bogus_irq_restore(); \ > - raw_local_irq_restore(flags); \ > - } while (0) > +#define local_irq_restore(flags) do { raw_local_irq_restore(flags); } while (0) > #define safe_halt() do { raw_safe_halt(); } while (0) > > #endif /* CONFIG_TRACE_IRQFLAGS */
| |