From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-181.mta0.migadu.com (out-181.mta0.migadu.com [91.218.175.181]) (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 B962630B53B for ; Tue, 27 Jan 2026 11:07:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.181 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769512043; cv=none; b=MxmxpTg0LW1n1LzjVSFdTqfg4tPucbQfYS5nLc0UmhF0DcVtmCQrS3BILXWUgu5b86Fx6ynhO6qYGXY3eMocTYSz6bx/qC0KwSwJn54nvVHpgmnFu0M+zYTjj1EWgorqpelWxLH1fmce9RIb4EknOJ392CbHKDyN27qEinsaZAI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769512043; c=relaxed/simple; bh=3VLn2nqn0aCJhf5PUKEEbnPyJ2hLRrEI5shV1agTPUk=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=FU7vm7zz8RQRS/LUiEsZRUTRAvJZnt+obnYWsMCA0ZRJpV1T5zczY4tE167RXKKqvlA3o3RVrdW7kApZ/+1QURFRETGfJ4D9tWZkIDNRaP+G08LgsvMECyeMJrgC9BYl9NnjsKISP1xtw4ucJI+2Ie4Q2R4NDvCAR9UyST8iJLM= 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=Hgin/0GL; arc=none smtp.client-ip=91.218.175.181 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="Hgin/0GL" 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=1769512039; 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=KiMnHwHAnPOzq3BGdd+rflxyUVjNNIBkrIV+1F5w07w=; b=Hgin/0GLj5PzK3VKQx43pALuPboksKO78dNSLos12vWcC9k9yuR0SkrKI+3LJ3cpSu+trX IpzGTHvkhgCJemGg2YOW6CVzpuGeTuamrwtpV1USPidf7nlo5yXigYVvbme0EkzRGp1jjT oETP17PiBVExDJTb0bt/IA6nDc7ejAo= 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: Tue, 27 Jan 2026 12:06:52 +0100 Message-ID: <20260127110654.436657-1-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); -- Thorsten Blum GPG: 1D60 735E 8AEF 3BE4 73B6 9D84 7336 78FD 8DFE EAD4