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From:   Will Deacon <will@kernel.org>
To:     Masami Hiramatsu <mhiramat@kernel.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Jisheng Zhang <Jisheng.Zhang@synaptics.com>
Cc:     kernel-team@android.com, Will Deacon <will@kernel.org>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Liao Chang <liaochang1@huawei.com>
Subject: Re: [PATCH] arm64: kprobes: Restore local irqflag if kprobes is cancelled
Date:   Tue, 13 Apr 2021 18:49:22 +0100
Message-Id: <161830261625.3702418.8292373763983690459.b4-ty@kernel.org>
In-Reply-To: <20210412174101.6bfb0594@xhacker.debian>
References: <20210412174101.6bfb0594@xhacker.debian>
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Precedence: bulk

On Mon, 12 Apr 2021 17:41:01 +0800, Jisheng Zhang wrote:
> If instruction being single stepped caused a page fault, the kprobes
> is cancelled to let the page fault handler continue as a normal page
> fault. But the local irqflags are disabled so cpu will restore pstate
> with DAIF masked. After pagefault is serviced, the kprobes is
> triggerred again, we overwrite the saved_irqflag by calling
> kprobes_save_local_irqflag(). NOTE, DAIF is masked in this new saved
> irqflag. After kprobes is serviced, the cpu pstate is retored with
> DAIF masked.
> 
> [...]

Applied to arm64 (for-next/fixes), thanks!

[1/1] arm64: kprobes: Restore local irqflag if kprobes is cancelled
      https://git.kernel.org/arm64/c/738fa58ee132

Cheers,
-- 
Will

https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev