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From: peterz@infradead.org
To: Marco Elver <elver@google.com>
Cc: jgross@suse.com, fenghua.yu@intel.com, yu-cheng.yu@intel.com,
	tony.luck@intel.com, dave.hansen@linux.intel.com,
	syzkaller-bugs@googlegroups.com, linux-kernel@vger.kernel.org,
	kasan-dev@googlegroups.com,
	virtualization@lists.linux-foundation.org, mingo@redhat.com,
	bp@alien8.de, hpa@zytor.com, tglx@linutronix.de,
	syzbot <syzbot+8db9e1ecde74e590a657@syzkaller.appspotmail.com>,
	x86@kernel.org
Subject: Re: [PATCH] x86/paravirt: Add missing noinstr to arch_local*() helpers
Date: Wed, 5 Aug 2020 15:42:32 +0200	[thread overview]
Message-ID: <20200805134232.GR2674@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20200805132629.GA87338@elver.google.com>

On Wed, Aug 05, 2020 at 03:26:29PM +0200, Marco Elver wrote:
> Add missing noinstr to arch_local*() helpers, as they may be called from
> noinstr code.
> 
> On a KCSAN config with CONFIG_PARAVIRT=y, syzbot stumbled across corrupt

Cute, so I've been working on adding objtool support for this a little:

  https://lkml.kernel.org/r/20200803143231.GE2674@hirez.programming.kicks-ass.net

> diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
> index 3d2afecde50c..a606f2ba2b5e 100644
> --- a/arch/x86/include/asm/paravirt.h
> +++ b/arch/x86/include/asm/paravirt.h
> @@ -760,27 +760,27 @@ bool __raw_callee_save___native_vcpu_is_preempted(long cpu);
>  	((struct paravirt_callee_save) { func })
>  
>  #ifdef CONFIG_PARAVIRT_XXL
> -static inline notrace unsigned long arch_local_save_flags(void)
> +static inline noinstr unsigned long arch_local_save_flags(void)
>  {
>  	return PVOP_CALLEE0(unsigned long, irq.save_fl);
>  }
>  
> -static inline notrace void arch_local_irq_restore(unsigned long f)
> +static inline noinstr void arch_local_irq_restore(unsigned long f)
>  {
>  	PVOP_VCALLEE1(irq.restore_fl, f);
>  }
>  
> -static inline notrace void arch_local_irq_disable(void)
> +static inline noinstr void arch_local_irq_disable(void)
>  {
>  	PVOP_VCALLEE0(irq.irq_disable);
>  }
>  
> -static inline notrace void arch_local_irq_enable(void)
> +static inline noinstr void arch_local_irq_enable(void)
>  {
>  	PVOP_VCALLEE0(irq.irq_enable);
>  }
>  
> -static inline notrace unsigned long arch_local_irq_save(void)
> +static inline noinstr unsigned long arch_local_irq_save(void)
>  {
>  	unsigned long f;
>  

Shouldn't we __always_inline those? They're going to be really small.
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       reply	other threads:[~2020-08-05 13:42 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <0000000000007d3b2d05ac1c303e@google.com>
     [not found] ` <20200805132629.GA87338@elver.google.com>
2020-08-05 13:42   ` peterz [this message]
     [not found]     ` <20200805135940.GA156343@elver.google.com>
2020-08-05 14:12       ` [PATCH] x86/paravirt: Add missing noinstr to arch_local*() helpers peterz
2020-08-05 14:17         ` Jürgen Groß
2020-08-05 14:17         ` peterz
     [not found]           ` <CANpmjNN6FWZ+MsAn3Pj+WEez97diHzqF8hjONtHG15C2gSpSgw@mail.gmail.com>
     [not found]             ` <CANpmjNNy3XKQqgrjGPPKKvXhAoF=mae7dk8hmoS4k4oNnnB=KA@mail.gmail.com>
     [not found]               ` <20200806074723.GA2364872@elver.google.com>
2020-08-06 11:32                 ` peterz
     [not found]                   ` <20200806131702.GA3029162@elver.google.com>
     [not found]                     ` <CANpmjNNqt8YrCad4WqgCoXvH47pRXtSLpnTKhD8W8+UpoYJ+jQ@mail.gmail.com>
     [not found]                       ` <CANpmjNO860SHpNve+vaoAOgarU1SWy8o--tUWCqNhn82OLCiew@mail.gmail.com>
2020-08-07  9:24                         ` Jürgen Groß
     [not found]                           ` <20200807095032.GA3528289@elver.google.com>
2020-08-07 10:35                             ` Jürgen Groß
     [not found]                               ` <20200807113838.GA3547125@elver.google.com>
2020-08-07 12:04                                 ` Jürgen Groß
     [not found]                                   ` <CANpmjNPau_DEYadey9OL+iFZKEaUTqnFnyFs1dU12o00mg7ofA@mail.gmail.com>
     [not found]                                     ` <20200807151903.GA1263469@elver.google.com>
     [not found]                                       ` <CANpmjNM1jASqCFYZpteVrZCa2V2D_DbXaqvoCV_Ac2boYfDXnQ@mail.gmail.com>
2020-08-11  7:04                                         ` Jürgen Groß
2020-08-11  7:41                                       ` Peter Zijlstra
2020-08-11  7:57                                         ` Jürgen Groß
2020-08-11  8:12                                           ` Peter Zijlstra
2020-08-11  8:18                                             ` Jürgen Groß
2020-08-11  8:38                                             ` Jürgen Groß
2020-08-11  9:20                                               ` peterz
2020-08-11  9:46                                                 ` peterz
2020-08-11 20:17                                                   ` peterz
     [not found]                                                     ` <20200812080650.GA3894595@elver.google.com>
2020-08-12  8:18                                                       ` peterz
2020-08-12  8:57                                                         ` peterz

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