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Message-ID: <1c260ab1-d4c0-48e6-bf2b-df69bf083d27@intel.com>
Date: Mon, 22 Jan 2024 16:25:58 -0800
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH bpf 3/3] selftest/bpf: Test the read of vsyscall page
 under x86-64
Content-Language: en-US
To: Hou Tao <houtao@huaweicloud.com>, <x86@kernel.org>, <bpf@vger.kernel.org>
CC: Dave Hansen <dave.hansen@linux.intel.com>, Andy Lutomirski
	<luto@kernel.org>, Peter Zijlstra <peterz@infradead.org>, Thomas Gleixner
	<tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>, Borislav Petkov
	<bp@alien8.de>, "H . Peter Anvin" <hpa@zytor.com>,
	<linux-kernel@vger.kernel.org>, xingwei lee <xrivendell7@gmail.com>, "Jann
 Horn" <jannh@google.com>, <houtao1@huawei.com>
References: <20240119073019.1528573-1-houtao@huaweicloud.com>
 <20240119073019.1528573-4-houtao@huaweicloud.com>
From: Sohil Mehta <sohil.mehta@intel.com>
In-Reply-To: <20240119073019.1528573-4-houtao@huaweicloud.com>
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On 1/18/2024 11:30 PM, Hou Tao wrote:

> vsyscall page could be disabled by CONFIG_LEGACY_VSYSCALL_NONE or
> vsyscall=none boot cmd-line, but it doesn't affect the reproduce of the
> problem and the returned error codes.
> 

With vsyscall=emulate a direct read of the vsyscall address from
userspace is expected to go through. This is mode deprecated so maybe it
wouldn't matter much. Without the fix in patch 2/3, do you see the same
behavior with vsyscall=emulate set in the cmdline?

Sohil