From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-187.mta1.migadu.com (out-187.mta1.migadu.com [95.215.58.187]) (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 E9EFB23ABB3 for ; Tue, 9 Sep 2025 10:25:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.187 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757413553; cv=none; b=U+Sn2f+fHv9fAQ0Nu6O3OD6CMm6+gQH5lMw2iN/jVEM1tNCKK+aVZrFw7okzA8197z3UFZcNHuPLaWB1qXMo73+SWy/9HVysQp3zV1axxVd9n71RiQCPqGVs9xHcfcn1NKpebYiWpm0gUgepW0w+VENcxGhA2QRUuRNx0t2r/88= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757413553; c=relaxed/simple; bh=p5LhXEGcLou/f6INyxNHsNzvlEz6x7HFoLOSbFUaVhA=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=aQcDOj9tnv0cH3CuuT9RF5HdBJrZUt1gAsYFW//y/AELuEOFvMSwVLDrmwq+ePY15vP97ZC0F6cLUKSnBUu1HHpYMLIU9Tj4sGoAFYGae60TiDzboWBzp6/GCzVbRw3yopjsECqwAAtcwnnGFzpETjCNyoV6FM5N5FCMdsixqv0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=bOzGirjN; arc=none smtp.client-ip=95.215.58.187 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="bOzGirjN" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1757413546; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=ejyOVWNZnM4N3Ivi3K/PAopR0Lc4S3yDQSFJewEL248=; b=bOzGirjNc89HFYUO7bNBKxqLRtE6F/lgIIgN3nre+0+sMsO9BDJv4t3oByr5BnzI6VYtU6 A50lAWW+/SrsIVMEp3qCA5EmWZOOned6SOI0QkGT9qR3E9vWGtCrx8bwiQ/M2dSkFxGYFY aFSw28tR9jSscq0VwVjpkNll4VSkXBY= From: Thorsten Blum To: Alexander Shishkin , Maxime Coquelin , Alexandre Torgue Cc: Thorsten Blum , linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/2] stm class: Replace kmalloc() + copy_from_user() with memdup_user() Date: Tue, 9 Sep 2025 12:25:12 +0200 Message-ID: <20250909102512.694203-2-thorsten.blum@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT Replace kmalloc() followed by copy_from_user() with memdup_user() to improve and simplify stm_char_write(). Allocate and copy only 'count' bytes instead of 'count + 1' since the extra byte is unused. No functional changes intended. Signed-off-by: Thorsten Blum --- drivers/hwtracing/stm/core.c | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-) diff --git a/drivers/hwtracing/stm/core.c b/drivers/hwtracing/stm/core.c index cdba4e875b28..5834f796e86b 100644 --- a/drivers/hwtracing/stm/core.c +++ b/drivers/hwtracing/stm/core.c @@ -645,15 +645,9 @@ static ssize_t stm_char_write(struct file *file, const char __user *buf, return err; } - kbuf = kmalloc(count + 1, GFP_KERNEL); - if (!kbuf) - return -ENOMEM; - - err = copy_from_user(kbuf, buf, count); - if (err) { - kfree(kbuf); - return -EFAULT; - } + kbuf = memdup_user(buf, count); + if (IS_ERR(kbuf)) + return PTR_ERR(kbuf); pm_runtime_get_sync(&stm->dev); -- 2.51.0