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 5A7913FBEB1 for ; Thu, 30 Apr 2026 11:55:37 +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=1777550137; cv=none; b=Qzt5d3KJ4Ne3QDvver237Qsf+Rl6y3crcgSGR3pul0pwqumMMBvacEvmLQ8zRjjhKKZC73kAvt8T69zFSxR37sVjW/49A1eLWY91EcL0g8YHopJYWC63TccBayX3OlThl1wetK09zqfhroxjdMwPRJM8bpuR+ovqElty3Pt4RuE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777550137; c=relaxed/simple; bh=I9TQS4XNBshsRkHXkfB/pIgsxdT4FZJf4Cz5n2lf9II=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=skbDlIcZWzrEytlxjYCzVfPv/gJ39/PEIpXqNeWImy0T5t7HLVtWqfzMFgXNbs20LPfsM94mvgV8igiXw8uHjxzYJqPeITwQ+xS0cmTPRBkY0b5qnvg0Z4/T7JsDuHyOpGdQo9VgknxVebEeCFgEVroXD9WWVniMWHKd3Ix8l6M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=CNHARitD; 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="CNHARitD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1189DC2BCC4; Thu, 30 Apr 2026 11:55:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777550136; bh=I9TQS4XNBshsRkHXkfB/pIgsxdT4FZJf4Cz5n2lf9II=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date:From; b=CNHARitDlF5R9aE69HDNq74LBdkWS6+qc+QS63MR6IN5CYx8AxJL0vYu/ViaBZRVV NQh0CWeUZiCUYv0fO5UOpgPvy4OnwWWW1Ii3EanQ7bmvlne56HjgeDfAijw7NfkUuL JtRInBbwlz8Yr4RFxocOnLAvFdHDrdSKBs6NsSYSwhFd7xt61RpbYWKRrNgVrN/Uul mg7YiDtgj+g9DX0FfmYlbuwMh+n9bzmSSrixwEHLaZqqTBtCRYhhg80UQBP6fwAD5Z YslZ0bvd9eFZ4/U+Ss2eBkVtUXghN7VzmjTE8YR4aiWkPvV1oNnNkiYAs0wfQGKrfH DvdYsjyYrf34g== From: sashiko-bot@kernel.org Subject: Re: [PATCH v2 2/3] DO NOT MERGE: arm64: perf: Add skip_vmio parameter to control device memory callchain guard Reply-To: sashiko@lists.linux.dev To: "Fredrik Markstrom" Cc: linux-perf-users@vger.kernel.org In-Reply-To: <20260430-master-with-pfix-v3-v2-2-bd526ec04a75@est.tech> References: <20260430-master-with-pfix-v3-v2-2-bd526ec04a75@est.tech> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Thu, 30 Apr 2026 11:55:35 +0000 Message-Id: <20260430115536.1189DC2BCC4@smtp.kernel.org> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Thank you for your contribution! Sashiko AI review found 1 potential issue(= s) to consider: - [High] The commit is explicitly marked 'DO NOT MERGE' and introduces a mo= dule parameter to bypass a safety guard, intentionally triggering a kernel = panic. -- commit 955a332efd3c97ad086c64a2f8f7a0cd30dbaea7 Author: Fredrik Markstrom DO NOT MERGE: arm64: perf: Add skip_vmio parameter to control device memory= callchain guard This commit introduces a module parameter to dynamically disable the device memory guard during user callchain unwinding. Disabling this guard allows perf to follow frame pointers into device memory, intentionally triggering a synchronous external abort and kernel panic on arm64 for testing purposes. > DO NOT MERGE: arm64: perf: Add skip_vmio parameter to control device memo= ry callchain guard Should this patch be dropped from the queue, given the subject is explicitly marked "DO NOT MERGE"? [ ... ] > diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrac= e.c > index 4a28df9bbe763..19b5251f214f2 100644 > --- a/arch/arm64/kernel/stacktrace.c > +++ b/arch/arm64/kernel/stacktrace.c > @@ -123,6 +124,10 @@ static bool range_is_device_mem(unsigned long start,= unsigned long size) > return false; > } > =20 > +static bool skip_vmio =3D true; > +module_param_unsafe(skip_vmio, bool, 0600); > +MODULE_PARM_DESC(skip_vmio, "Skip device memory during user callchain un= winding"); > + Is it intended to merge this debug module parameter into the mainline kerne= l? The commit message notes that disabling this guard intentionally triggers a synchronous external abort and kernel panic. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260430-master-wit= h-pfix-v3-v2-0-bd526ec04a75@est.tech?part=3D2