From: Nathan Chancellor <nathan@kernel.org>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com,
will@kernel.org
Subject: Re: [PATCH] arm64: kprobes: Drop ID map text from kprobes blacklist
Date: Sun, 5 Feb 2023 11:37:24 -0700 [thread overview]
Message-ID: <Y9/3ZPxfpcZ+JFnf@dev-arch.thelio-3990X> (raw)
In-Reply-To: <20230204101807.2862321-1-ardb@kernel.org>
On Sat, Feb 04, 2023 at 11:18:07AM +0100, Ard Biesheuvel wrote:
> The ID mapped text region is never accessed via the normal kernel
> mapping of text, and so it was moved into .rodata instead. This means it
> is no longer considered as a suitable place for kprobes by default, and
> the explicit blacklist is unnecessary, and actually results in an error
> message at boot:
>
> kprobes: Failed to populate blacklist (error -22), kprobes not restricted, be careful using them!
>
> So stop blacklisting the ID map text explicitly.
>
> Fixes: af7249b317e4d0b3d ("arm64: kernel: move identity map out of .text mapping")
> Reported-by: Nathan Chancellor <nathan@kernel.org>
> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Thank you for the quick fix!
Tested-by: Nathan Chancellor <nathan@kernel.org>
> ---
> arch/arm64/kernel/probes/kprobes.c | 4 ----
> 1 file changed, 4 deletions(-)
>
> diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c
> index f35d059a9a366fa6..70b91a8c6bb3f358 100644
> --- a/arch/arm64/kernel/probes/kprobes.c
> +++ b/arch/arm64/kernel/probes/kprobes.c
> @@ -387,10 +387,6 @@ int __init arch_populate_kprobe_blacklist(void)
> (unsigned long)__irqentry_text_end);
> if (ret)
> return ret;
> - ret = kprobe_add_area_blacklist((unsigned long)__idmap_text_start,
> - (unsigned long)__idmap_text_end);
> - if (ret)
> - return ret;
> ret = kprobe_add_area_blacklist((unsigned long)__hyp_text_start,
> (unsigned long)__hyp_text_end);
> if (ret || is_kernel_in_hyp_mode())
> --
> 2.39.1
>
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next prev parent reply other threads:[~2023-02-05 18:38 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-04 10:18 [PATCH] arm64: kprobes: Drop ID map text from kprobes blacklist Ard Biesheuvel
2023-02-05 18:37 ` Nathan Chancellor [this message]
2023-02-07 10:15 ` Mark Rutland
2023-02-07 18:54 ` Catalin Marinas
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