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From: Masami Hiramatsu <mhiramat@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, mingo@kernel.org,
	rostedt@goodmis.org, naveen.n.rao@linux.vnet.ibm.com,
	ananth@linux.ibm.com, x86@kernel.org
Subject: Re: [PATCH 2/2] x86,kprobes: WARN if kprobes tries to handle a fault
Date: Tue, 25 May 2021 23:21:03 +0900	[thread overview]
Message-ID: <20210525232103.9d79ff5e396cddd2a9eb818f@kernel.org> (raw)
In-Reply-To: <20210525073213.660594073@infradead.org>

On Tue, 25 May 2021 09:25:20 +0200
Peter Zijlstra <peterz@infradead.org> wrote:

> With the removal of kprobe::handle_fault there is no reason left that
> kprobe_page_fault() would ever return true on x86, make sure it
> doesn't happen by accident.

OK, this is reasonable to me.

Acked-by: Masami Hiramatsu <mhiramat@kernel.org>

Thank you!

> 
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> ---
>  arch/x86/mm/fault.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> --- a/arch/x86/mm/fault.c
> +++ b/arch/x86/mm/fault.c
> @@ -1186,7 +1186,7 @@ do_kern_addr_fault(struct pt_regs *regs,
>  		return;
>  
>  	/* kprobes don't want to hook the spurious faults: */
> -	if (kprobe_page_fault(regs, X86_TRAP_PF))
> +	if (WARN_ON_ONCE(kprobe_page_fault(regs, X86_TRAP_PF)))
>  		return;
>  
>  	/*
> @@ -1239,7 +1239,7 @@ void do_user_addr_fault(struct pt_regs *
>  	}
>  
>  	/* kprobes don't want to hook the spurious faults: */
> -	if (unlikely(kprobe_page_fault(regs, X86_TRAP_PF)))
> +	if (WARN_ON_ONCE(kprobe_page_fault(regs, X86_TRAP_PF)))
>  		return;
>  
>  	/*
> 
> 


-- 
Masami Hiramatsu <mhiramat@kernel.org>

  reply	other threads:[~2021-05-25 14:21 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-25  7:25 [PATCH 0/2] kprobes: Remove kprobe::fault_handler Peter Zijlstra
2021-05-25  7:25 ` [PATCH 1/2] " Peter Zijlstra
2021-05-25 14:06   ` Masami Hiramatsu
2021-05-26 10:50   ` Naveen N. Rao
2021-05-26 13:51     ` Masami Hiramatsu
2021-06-01 12:01   ` [PATCH] kprobes: Do not increment probe miss count in the fault handler Naveen N. Rao
2021-06-01 13:20     ` Peter Zijlstra
2021-06-01 23:48       ` Masami Hiramatsu
2021-06-04 13:38     ` [tip: perf/core] " tip-bot2 for Naveen N. Rao
2021-06-01 14:04   ` [tip: perf/core] kprobes: Remove kprobe::fault_handler tip-bot2 for Peter Zijlstra
2021-05-25  7:25 ` [PATCH 2/2] x86,kprobes: WARN if kprobes tries to handle a fault Peter Zijlstra
2021-05-25 14:21   ` Masami Hiramatsu [this message]
2021-06-01 14:04   ` [tip: perf/core] " tip-bot2 for Peter Zijlstra

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