From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-189.mta1.migadu.com (out-189.mta1.migadu.com [95.215.58.189]) (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 D599D29BDB1 for ; Fri, 17 Oct 2025 10:28:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.189 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760696911; cv=none; b=FRU3cSyFCJDBYs2AT+aMCDedGT/EHvmklOsMVSEDQZGuuqRcAoV890uqw/DtR2sEDx7w7EwKxfBnSUnCrWL0/PNn4w5J0Uxt5xzIq1I8w4EAEfVhj1V7es9uFDG+Bv5qMNeE9j5ZsJwunGVwbfVKXQp2eQ0aOCf+gyQuy+dWZkI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760696911; c=relaxed/simple; bh=cwbKcDkqcazpSY0xW+hoZDJvn6Vdm8ZtWoRuzYArkyE=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=E4VPfWBr80A7+VVi/X4tZVXRUKQtH8y9CJ5vh7XKDYzlhRJ8UgH9J1Gj57xNC+vP/nDBMKdjugzWaDjGfB4ejO/J+sY60onJyurs0KZtJtLqrbo4biVpgcqWn/5LpghkgeXj1cb0sZHbEKfLjv8Xw9sLAQA6fcyhXrGsu/qkCWU= 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=LQG4n4Va; arc=none smtp.client-ip=95.215.58.189 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="LQG4n4Va" 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=1760696907; 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=W1IDrz3RmQ+DjnJHgkvZJfeGuFV4FYY3VXTJn4UzdsY=; b=LQG4n4Vai/wW3aF62q1eiUNmJjL5j3yRF7CeP3SbZ8TiUo9B8fklD1tcXvOIKbIQDhkTN+ BuQVstW4GNimda8ZTHaPXOaCfuAXBZ1TGQCSEYCQRj/yTtLznR5VJlXq8+B2m/kuwNgGWI TN1vWPrCLBg0AHc+mvYBIoymOLwKMik= 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 RESEND 1/2] stm class: Replace kmalloc + copy_from_user with memdup_user Date: Fri, 17 Oct 2025 12:27:42 +0200 Message-ID: <20251017102743.75394-2-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 simplify and improve stm_char_write(). Allocate and copy only 'count' bytes instead of 'count + 1' since the extra byte is unused. 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