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From: Peter Zijlstra <peterz@infradead.org>
To: Lai Jiangshan <laijs@linux.alibaba.com>
Cc: linux-kernel@vger.kernel.org, Andy Lutomirski <luto@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	x86@kernel.org
Subject: Re: [RFC PATCH 0/5] x86/hw_breakpoint: protects more cpu entry data
Date: Mon, 25 May 2020 17:25:17 +0200	[thread overview]
Message-ID: <20200525152517.GY325280@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20200525145102.122557-1-laijs@linux.alibaba.com>

On Mon, May 25, 2020 at 02:50:57PM +0000, Lai Jiangshan wrote:
> Hello
> 
> The patchset is based on (tag: entry-v9-the-rest, tglx-devel/x86/entry).
> And it is complement of 3ea11ac991d
> ("x86/hw_breakpoint: Prevent data breakpoints on cpu_entry_area").
> 
> After reading the code, we can see that more data needs to be protected
> against hw_breakpoint, otherwise it may cause
> dangerous/recursive/unwanted #DB.
> 
> 
> Lai Jiangshan (5):
>   x86/hw_breakpoint: add within_area() to check data breakpoints
>   x86/hw_breakpoint: Prevent data breakpoints on direct GDT
>   x86/hw_breakpoint: Prevent data breakpoints on per_cpu cpu_tss_rw

I think we can actually get rid of that #DB IST stack frobbing, also see
patches linked below.

>   x86/hw_breakpoint: Prevent data breakpoints on user_pcid_flush_mask

Should we disallow the full structure just to be sure?

>   x86/hw_breakpoint: Prevent data breakpoints on debug_idt_table

That's going away, see:

https://lkml.kernel.org/r/20200522204738.645043059@infradead.org

But yes, nice!


  parent reply	other threads:[~2020-05-25 15:25 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-25 14:50 Lai Jiangshan
2020-05-25 14:50 ` [RFC PATCH 1/5] x86/hw_breakpoint: add within_area() to check data breakpoints Lai Jiangshan
2020-05-25 14:50 ` [RFC PATCH 2/5] x86/hw_breakpoint: Prevent data breakpoints on direct GDT Lai Jiangshan
2020-05-25 14:51 ` [RFC PATCH 3/5] x86/hw_breakpoint: Prevent data breakpoints on per_cpu cpu_tss_rw Lai Jiangshan
2020-05-25 14:51 ` [RFC PATCH 4/5] x86/hw_breakpoint: Prevent data breakpoints on user_pcid_flush_mask Lai Jiangshan
2020-05-25 14:51 ` [RFC PATCH 5/5] x86/hw_breakpoint: Prevent data breakpoints on debug_idt_table Lai Jiangshan
2020-05-25 15:25 ` Peter Zijlstra [this message]
2020-05-26  1:42   ` [RFC PATCH V2 0/7] x86/DB: protects more cpu entry data and Lai Jiangshan
2020-05-26  1:42     ` [RFC PATCH V2 1/7] x86/hw_breakpoint: add within_area() to check data breakpoints Lai Jiangshan
2020-05-30  9:57       ` [tip: x86/entry] x86/hw_breakpoint: Add " tip-bot2 for Lai Jiangshan
2020-05-26  1:42     ` [RFC PATCH V2 2/7] x86/hw_breakpoint: Prevent data breakpoints on direct GDT Lai Jiangshan
2020-05-30  9:57       ` [tip: x86/entry] " tip-bot2 for Lai Jiangshan
2020-05-26  1:42     ` [RFC PATCH V2 3/7] x86/hw_breakpoint: Prevent data breakpoints on per_cpu cpu_tss_rw Lai Jiangshan
2020-05-30  9:57       ` [tip: x86/entry] " tip-bot2 for Lai Jiangshan
2020-05-26  1:42     ` [RFC PATCH V2 4/7] x86/hw_breakpoint: Prevent data breakpoints on user_pcid_flush_mask Lai Jiangshan
2020-05-26  4:17       ` Andy Lutomirski
2020-05-26  4:31         ` Lai Jiangshan
2020-05-26  4:38           ` Andy Lutomirski
2020-05-26  5:48             ` Lai Jiangshan
2020-05-30  9:57       ` [tip: x86/entry] " tip-bot2 for Lai Jiangshan
2020-05-26  1:42     ` [RFC PATCH V2 5/7] x86/entry: don't shift stack on #DB Lai Jiangshan
2020-05-26  9:10       ` Peter Zijlstra
2020-05-26  1:42     ` [RFC PATCH V2 6/7] x86/entry: is_debug_stack() don't check of DB1 stack Lai Jiangshan
2020-05-26  1:42     ` [RFC PATCH V2 7/7] x86/entry: remove DB1 stack and DB2 hole from cpu entry area Lai Jiangshan
2020-05-26  1:48   ` [RFC PATCH 0/5] x86/hw_breakpoint: protects more cpu entry data Lai Jiangshan

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