From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-176.mta1.migadu.com (out-176.mta1.migadu.com [95.215.58.176]) (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 9721132C33E for ; Fri, 14 Nov 2025 16:04:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.176 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763136274; cv=none; b=sCCBjQLn0L1tLe6X/++zTQe4sZXNwyRnkqOczhi0PRCtezo0qCsV0c9WV1CzHpA7IXCxRq9fdv7sic4HTTWX9YSnhKgen+WY2o+oCttW5Uwk/dEg2FJQmVmGcrh06kQ7DAWSMfqEXDoFzp3UcBATD/a7ebIw3XYwZX4I25GEuvU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763136274; c=relaxed/simple; bh=Xg5cMMvqNaqqOdKjWDp9LXGCHg4WdeesS7H8Di3E1wg=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=s1LDpqZpt3BQjvw7+zjLHuBHef6Ni+cCpBqb2yVQlydF+7hJG7OMq7uSTWfgmUXA1Kx46gLmLNzLt518nZaIb/vSp+JHEl4TAB4c9KoEYlDmoMoB+KxCF+ZqEFAHu6quPb10qHry236rGQ3M6HjNxKyIuLi1WTIGIV9vFhDuIE4= 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=bIA4w7bz; arc=none smtp.client-ip=95.215.58.176 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="bIA4w7bz" 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=1763136269; 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=QZlnloDVP5vmwxiC7EMfXur1lHp1LWIvnS5y5fvEpOE=; b=bIA4w7bzP88K201RhO5wgzEJc4E+yc81fX+/ClZ34zg3Ee855ptxF7vsJXwi4Xffp52W0k 3QD6nUyZBUOEdTiszymEMGmkm9nduLAmgLiAjr0CMakO0Ro4xBhgDd4Jxta9gZusRXO7SM D6MwQBNdufxYJ11gBziSzddjs0Nlakg= 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, 14 Nov 2025 17:04:14 +0100 Message-ID: <20251114160416.230513-1-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); -- 2.51.1