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Date: Tue, 23 Jan 2024 19:02:23 +0000
From: Mark Brown <broonie@kernel.org>
To: Kees Cook <keescook@chromium.org>
Cc: Russell King <linux@armlinux.org.uk>, Ard Biesheuvel <ardb@kernel.org>,
	Wang Kefeng <wangkefeng.wang@huawei.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Ben Hutchings <ben@decadent.org.uk>,
	linux-arm-kernel@lists.infradead.org,
	"Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>,
	Hugh Dickins <hughd@google.com>, linux-kernel@vger.kernel.org,
	linux-hardening@vger.kernel.org
Subject: Re: [PATCH] ARM: fault: Implement copy_from_kernel_nofault_allowed()
Message-ID: <4d46dafe-b5bd-4395-b680-94b11814f7c6@sirena.org.uk>
References: <20240123011238.work.301-kees@kernel.org>
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On Mon, Jan 22, 2024 at 05:12:38PM -0800, Kees Cook wrote:
> Under PAN emulation when dumping backtraces from things like the
> LKDTM EXEC_USERSPACE test[1], a double fault (which would hang a CPU)
> would happen because of dump_instr() attempting to read a userspace
> address. Make sure copy_from_kernel_nofault() does not attempt this
> any more.

This appears to fix the original issue:

   https://lava.sirena.org.uk/scheduler/job/497571

(though so did your earlier patch) so:

Tested-by: Mark Brown <broonie@kernel.org>

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