From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 19B3C3BADB2; Tue, 7 Apr 2026 14:30:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775572211; cv=none; b=VAEHLEUX2lUqM+odqUML2WU/wK15iAh2IDIEFXaC5OWEIqnwVyuU4q1NOBjTuwW+SFewjqTq86I1r3VR+9VOV3FQCHroHvc/A9m787m0xQyn5ZBsJFUYZTcWO4V/g3jWv/sDO4Z+bce9k5Vb2+Vvo5kRgmtroY+1yjKn5MyAClQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775572211; c=relaxed/simple; bh=H/ZjhYgrW3VND0oifQK7yUnQ24qHMPGKHi0BUoEY5sc=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=OpCvh10qD7m2IheSAHkO7lYFz3F+WeqJejuHi558CkVi2CVHSYWcHeax4VF/lnZjv8M4u9fEURqXyXch4z8bWOZEhLwQD+YKrvc2Tfhg7HtHjgvJvZjBhjTfzo0j/gDzjvAummGymW/LJF562ldA5v/yNeL3x3KBe0o4jCEyu2g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=LvCt7trh; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="LvCt7trh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C6D1AC2BCB0; Tue, 7 Apr 2026 14:30:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1775572211; bh=H/ZjhYgrW3VND0oifQK7yUnQ24qHMPGKHi0BUoEY5sc=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=LvCt7trhYrin7vmw0KGlxThv1JqXPC/SnLO0rfKa8S1mowBnzeXYbGqNm+DGZDIPm Ve+KHt7WItbaxsfYzUsa6aVYZw8eMMZYEM7p/t86J88d+81PryhHYYUzpz84r3DqKb 6lyviNyMOSHm4QrUDAhsaAqeDpx0R1kfs5RohacPgzLpQ4szxwJX05DuAZIxDQTfbn KMG0XZhgn9y+5R94Tmw2lrWVdH00wkMbO9Iltfgg+x72Ny6RrYmb2sB11vAzkRdab0 0p9I3pwQ72lkrxInh1wj80M+GVT/mesFaizqDmEJlGlWs8DfR0uf2wHtOYbWa2SBI9 hZXx36JxqEvyA== From: "Rob Herring (Arm)" Date: Tue, 07 Apr 2026 09:29:43 -0500 Subject: [PATCH v4 1/6] arm64: hw_breakpoint: Disallow breakpoints in no kprobe code Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260407-arm-debug-8-9-v4-1-a4864e69b0ea@kernel.org> References: <20260407-arm-debug-8-9-v4-0-a4864e69b0ea@kernel.org> In-Reply-To: <20260407-arm-debug-8-9-v4-0-a4864e69b0ea@kernel.org> To: Will Deacon , Mark Rutland , Catalin Marinas , Jonathan Corbet , Shuah Khan Cc: Anshuman Khandual , linux-arm-kernel@lists.infradead.org, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org X-Mailer: b4 0.15-dev Taking debug exceptions while manipulating the breakpoints is likely to be unsafe. The setting kprobes in the breakpoint code is already forbidden, but the setting of h/w breakpoints is not. Copy what x86 does and exclude breakpoints that fall within the kprobe section. Signed-off-by: Rob Herring (Arm) --- arch/arm64/kernel/hw_breakpoint.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/arch/arm64/kernel/hw_breakpoint.c b/arch/arm64/kernel/hw_breakpoint.c index ab76b36dce82..38fbd67b2a6e 100644 --- a/arch/arm64/kernel/hw_breakpoint.c +++ b/arch/arm64/kernel/hw_breakpoint.c @@ -418,6 +418,16 @@ static int arch_build_bp_info(struct perf_event *bp, /* Type */ switch (attr->bp_type) { case HW_BREAKPOINT_X: + /* + * We don't allow kernel breakpoints in places that are not + * acceptable for kprobes. On non-kprobes kernels, we don't + * allow kernel breakpoints at all. + */ + if (attr->bp_addr >= TASK_SIZE_MAX) { + if (within_kprobe_blacklist(attr->bp_addr)) + return -EINVAL; + } + hw->ctrl.type = ARM_BREAKPOINT_EXECUTE; break; case HW_BREAKPOINT_R: -- 2.53.0