Messages in this thread | | | From | Thomas Gleixner <> | Subject | Re: [PATCH v4 7/9] kentry: Add debugging checks for proper kentry API usage | Date | Fri, 19 Mar 2021 17:17:47 +0100 |
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On Wed, Mar 17 2021 at 11:12, Andy Lutomirski wrote: > + > +#define DEBUG_ENTRY_WARN_ONCE(condition, format...) do {} while (0)
So we have a stub for !DEBUG
> +static __always_inline void kentry_cpu_depth_add(unsigned int n) {} > +static void kentry_cpu_depth_check(unsigned int n) {} > +static __always_inline void kentry_cpu_depth_sub(unsigned int n) {} > + > +#endif > + > /* See comment for enter_from_user_mode() in entry-common.h */ > static __always_inline void __enter_from_user_mode(struct pt_regs *regs) > { > + kentry_cpu_depth_add(1); > arch_check_user_regs(regs); > lockdep_hardirqs_off(CALLER_ADDR0); > > @@ -22,6 +78,14 @@ static __always_inline void __enter_from_user_mode(struct pt_regs *regs) > > instrumentation_begin(); > trace_hardirqs_off_finish(); > + > +#ifdef CONFIG_DEBUG_ENTRY
Why do we need that #ifdeffery all over the place?
> + DEBUG_ENTRY_WARN_ONCE( > + this_cpu_read(kentry_cpu_depth) != 1, > + "kentry: __enter_from_user_mode() called while kentry thought the CPU was in the kernel (%u)", > + this_cpu_read(kentry_cpu_depth));
Thanks,
tglx
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