From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 05BC147ACE9; Sat, 12 Sep 2026 12:41:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789216874; cv=none; b=mHVwQwSNNDwrwiYUBO/3vxhoOGmq2jlNpPRxKLPqOk0mscK3LULOS0gIT7Q4/ZsBiXKU/tIx74KznkfGrS3mbs2zhwf41HE2IMBrLWH7NF3GIgQLLJ23m1hnFik/9yxufjGrjkeLwu+tRvCpIHxZf073b9GjQ/sKgH9eAHWwPto= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789216874; c=relaxed/simple; bh=PluYur4FB2kkFOQI4nI+bfRu/lGmsiPAhOhuba45Phk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=mPHWniOdrK6wXi1VS07cT48IfJa7RH11h8/fs/kfFc2nu6/yNfwqw29z0Un0szfBmFkE6/OCJh5oBakpvnJHtql+xjIe1DJcQdc3MG+2DDLU5AIqOvLdD+rogBGG2y/ESeMJyKWtP5L0KpYtMCcQQ9QN7LtaI2PrEzEOdHULgyE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=DQKK3xQn; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="DQKK3xQn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 62B721F000FF; Sat, 12 Sep 2026 12:41:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789216872; bh=DR9EqTfYnijEySib10SK9GwXl9T9e6hLWW6TJZbpuVc=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=DQKK3xQnwdeVg33LflwP9aQjx51DyBSHgKcNcaAaTHSXyB3W4Yu1EFHcR1uRGREEs GGy9chNOaIaKqjdTko5iQOTqWrWkCUHsu2ixCegLfGbtnA+xM87WTARYAZpF/yTTik GlRlLpotL/Vq4RnV7pAHYqt3CDs0VhKLHsLUCvsU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Leo Yan , Will Deacon , Sasha Levin Subject: [PATCH 6.12 0824/1376] perf: arm_spe: Make wakeup range check overflow safe Date: Sat, 12 Sep 2026 08:54:10 +0200 Message-ID: <20260912065625.912355833@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065607.535295758@linuxfoundation.org> References: <20260912065607.535295758@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Leo Yan [ Upstream commit fcc5eaea2d234162dfb8258372dd897bc2a1b862 ] The current code checks whether the wakeup point is in the current writable range by comparing it with handle->head + handle->size. The perf AUX head is a monotonically increasing index, so that addition can overflow when head is close to ULONG_MAX. In that case, a wakeup point which is still inside the free space range can be missed. Use unsigned subtraction to compare the distance from head to wakeup against the handle->size. This can dismiss the issue when addition overflow. This is unlikely to happen in practice, but the change makes the watermark check logically correct. Fixes: d5d9696b0380 ("drivers/perf: Add support for ARMv8.2 Statistical Profiling Extension") Signed-off-by: Leo Yan Signed-off-by: Will Deacon Signed-off-by: Sasha Levin --- drivers/perf/arm_spe_pmu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/perf/arm_spe_pmu.c b/drivers/perf/arm_spe_pmu.c index 2fce871a1882d..5902ca3f057a1 100644 --- a/drivers/perf/arm_spe_pmu.c +++ b/drivers/perf/arm_spe_pmu.c @@ -467,7 +467,7 @@ static u64 __arm_spe_pmu_next_off(struct perf_output_handle *handle) * the page boundary following it. Keep the tail boundary if * that's lower. */ - if (handle->wakeup < (handle->head + handle->size) && head <= wakeup) + if ((handle->wakeup - handle->head) < handle->size && head <= wakeup) limit = min(limit, round_up(wakeup, PAGE_SIZE)); if (limit > head) -- 2.53.0