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From: Will Deacon <will@kernel.org>
To: Qais Yousef <qais.yousef@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Jean-Philippe Brucker <jean-philippe@linaro.org>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] arm64: kprobes: Fix Uexpected kernel BRK exception at EL1
Date: Fri, 22 Jan 2021 15:57:08 +0000	[thread overview]
Message-ID: <20210122155708.GA25088@willie-the-truck> (raw)
In-Reply-To: <20210122110909.3324607-1-qais.yousef@arm.com>

On Fri, Jan 22, 2021 at 11:09:09AM +0000, Qais Yousef wrote:
> I was hitting the below panic continuously when attaching kprobes to
> scheduler functions

[...]

> diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c
> index 89c64ada8732..66aac2881ba8 100644
> --- a/arch/arm64/kernel/probes/kprobes.c
> +++ b/arch/arm64/kernel/probes/kprobes.c
> @@ -352,8 +352,8 @@ kprobe_breakpoint_ss_handler(struct pt_regs *regs, unsigned int esr)
>  	unsigned long addr = instruction_pointer(regs);
>  	struct kprobe *cur = kprobe_running();
>  
> -	if (cur && (kcb->kprobe_status == KPROBE_HIT_SS)
> -	    && ((unsigned long)&cur->ainsn.api.insn[1] == addr)) {
> +	if (cur && (kcb->kprobe_status & (KPROBE_HIT_SS | KPROBE_REENTER)) &&
> +	    ((unsigned long)&cur->ainsn.api.insn[1] == addr)) {
>  		kprobes_restore_local_irqflag(kcb, regs);
>  		post_kprobe_handler(cur, kcb, regs);

Acked-by: Will Deacon <will@kernel.org>

Catalin can pick this up for 5.11.

Will

WARNING: multiple messages have this Message-ID (diff)
From: Will Deacon <will@kernel.org>
To: Qais Yousef <qais.yousef@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	linux-kernel@vger.kernel.org,
	Masami Hiramatsu <mhiramat@kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	Jean-Philippe Brucker <jean-philippe@linaro.org>
Subject: Re: [PATCH] arm64: kprobes: Fix Uexpected kernel BRK exception at EL1
Date: Fri, 22 Jan 2021 15:57:08 +0000	[thread overview]
Message-ID: <20210122155708.GA25088@willie-the-truck> (raw)
In-Reply-To: <20210122110909.3324607-1-qais.yousef@arm.com>

On Fri, Jan 22, 2021 at 11:09:09AM +0000, Qais Yousef wrote:
> I was hitting the below panic continuously when attaching kprobes to
> scheduler functions

[...]

> diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c
> index 89c64ada8732..66aac2881ba8 100644
> --- a/arch/arm64/kernel/probes/kprobes.c
> +++ b/arch/arm64/kernel/probes/kprobes.c
> @@ -352,8 +352,8 @@ kprobe_breakpoint_ss_handler(struct pt_regs *regs, unsigned int esr)
>  	unsigned long addr = instruction_pointer(regs);
>  	struct kprobe *cur = kprobe_running();
>  
> -	if (cur && (kcb->kprobe_status == KPROBE_HIT_SS)
> -	    && ((unsigned long)&cur->ainsn.api.insn[1] == addr)) {
> +	if (cur && (kcb->kprobe_status & (KPROBE_HIT_SS | KPROBE_REENTER)) &&
> +	    ((unsigned long)&cur->ainsn.api.insn[1] == addr)) {
>  		kprobes_restore_local_irqflag(kcb, regs);
>  		post_kprobe_handler(cur, kcb, regs);

Acked-by: Will Deacon <will@kernel.org>

Catalin can pick this up for 5.11.

Will

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  parent reply	other threads:[~2021-01-22 17:31 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-22 11:09 [PATCH] arm64: kprobes: Fix Uexpected kernel BRK exception at EL1 Qais Yousef
2021-01-22 11:09 ` Qais Yousef
2021-01-22 13:36 ` Masami Hiramatsu
2021-01-22 13:36   ` Masami Hiramatsu
2021-01-22 15:29   ` Qais Yousef
2021-01-22 15:29     ` Qais Yousef
2021-01-22 15:57 ` Will Deacon [this message]
2021-01-22 15:57   ` Will Deacon
2021-01-22 18:58 ` Catalin Marinas
2021-01-22 18:58   ` Catalin Marinas

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