linux-kernel - [PATCH][V2] drm: qxl: remove pr_info message, stops log spamming

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-Id: <20170912173422.14062-1-colin.king@canonical.com>
Date:   Tue, 12 Sep 2017 18:34:22 +0100
From:   Colin King <colin.king@...onical.com>
To:     Dave Airlie <airlied@...hat.com>,
        Gerd Hoffmann <kraxel@...hat.com>,
        David Airlie <airlied@...ux.ie>,
        virtualization@...ts.linux-foundation.org,
        dri-devel@...ts.freedesktop.org
Cc:     kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH][V2] drm: qxl: remove pr_info message, stops log spamming

From: Colin Ian King <colin.king@...onical.com>

Simply mmap'ing /dev/dri/card0 repeatedly will spam the kernel
log with qxl_mmap information messages. The following example code
illustrates this:

int main(void)
{
	int fd = open("/dev/dri/card0", O_RDONLY);
	if (fd == -1)
		err(1, "open failed");

	for (;;) {
		void *m = mmap(NULL, 4096, PROT_READ,
			MAP_SHARED, fd, 0);
		if (m != MAP_FAILED)
			munmap(m, 4096);
	}
}

Stop the spamming by removing the pr_info message. Since the mmap'ing
returns -EINVAL there is no need for the pr_info message.

Signed-off-by: Colin Ian King <colin.king@...onical.com>
---
 drivers/gpu/drm/qxl/qxl_ttm.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/qxl/qxl_ttm.c b/drivers/gpu/drm/qxl/qxl_ttm.c
index 7ecf8a4b9fe6..0f50c0b25a58 100644
--- a/drivers/gpu/drm/qxl/qxl_ttm.c
+++ b/drivers/gpu/drm/qxl/qxl_ttm.c
@@ -123,11 +123,8 @@ int qxl_mmap(struct file *filp, struct vm_area_struct *vma)
 	struct qxl_device *qdev;
 	int r;
 
-	if (unlikely(vma->vm_pgoff < DRM_FILE_PAGE_OFFSET)) {
-		pr_info("%s: vma->vm_pgoff (%ld) < DRM_FILE_PAGE_OFFSET\n",
-			__func__, vma->vm_pgoff);
+	if (unlikely(vma->vm_pgoff < DRM_FILE_PAGE_OFFSET))
 		return -EINVAL;
-	}
 
 	file_priv = filp->private_data;
 	qdev = file_priv->minor->dev->dev_private;
-- 
2.14.1