linux-kernel - Re: [PATCH 27/33] fbdev: remove FBINFO_MISC_USEREVENT around fb_blank

Open Source and information security mailing list archives

Message-ID: <20190520172008.GB27230@ravnborg.org>
Date:   Mon, 20 May 2019 19:20:08 +0200
From:   Sam Ravnborg <sam@...nborg.org>
To:     Daniel Vetter <daniel.vetter@...ll.ch>
Cc:     DRI Development <dri-devel@...ts.freedesktop.org>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        Intel Graphics Development <intel-gfx@...ts.freedesktop.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Michał Mirosław <mirq-linux@...e.qmqm.pl>,
        Yisheng Xie <ysxie@...mail.com>,
        Hans de Goede <hdegoede@...hat.com>,
        Mikulas Patocka <mpatocka@...hat.com>,
        Daniel Vetter <daniel.vetter@...el.com>,
        Peter Rosin <peda@...ntia.se>
Subject: Re: [PATCH 27/33] fbdev: remove FBINFO_MISC_USEREVENT around fb_blank

Hi Daniel.

> With the recursion broken in the previous patch we can drop the
> FBINFO_MISC_USEREVENT flag around calls to fb_blank - recursion
> prevention was it's only job.
> 
When grepping for FBINFO_MISC_USEREVENT I get a few hits not addressed
in the patch below:

drivers/video/fbdev/core/fbcon.c:                       if (!(info->flags & FBINFO_MISC_USEREVENT))
drivers/video/fbdev/core/fbmem.c:                       if (!ret && (flags & FBINFO_MISC_USEREVENT)) {
drivers/video/fbdev/core/fbmem.c:                               info->flags &= ~FBINFO_MISC_USEREVENT;
drivers/video/fbdev/core/fbmem.c:               info->flags |= FBINFO_MISC_USEREVENT;
drivers/video/fbdev/core/fbmem.c:               info->flags &= ~FBINFO_MISC_USEREVENT;
drivers/video/fbdev/core/fbmem.c:               info->flags |= FBINFO_MISC_USEREVENT;
drivers/video/fbdev/core/fbmem.c:               info->flags &= ~FBINFO_MISC_USEREVENT;
drivers/video/fbdev/core/fbsysfs.c:     fb_info->flags |= FBINFO_MISC_USEREVENT;
drivers/video/fbdev/core/fbsysfs.c:     fb_info->flags &= ~FBINFO_MISC_USEREVENT;
drivers/video/fbdev/core/fbsysfs.c:     fb_info->flags |= FBINFO_MISC_USEREVENT;
drivers/video/fbdev/core/fbsysfs.c:     fb_info->flags &= ~FBINFO_MISC_USEREVENT;
drivers/video/fbdev/ps3fb.c:                            info->flags |= FBINFO_MISC_USEREVENT;
drivers/video/fbdev/ps3fb.c:                            info->flags &= ~FBINFO_MISC_USEREVENT;
drivers/video/fbdev/sh_mobile_lcdcfb.c:  * FBINFO_MISC_USEREVENT flag is set. Since we do not want to fake a
include/linux/fb.h:#define FBINFO_MISC_USEREVENT          0x10000 /* event request

The use in ps3fb looks like a candidate for removal and this file is not
touch in this patch series, so I guess I did not miss it.

As I did not apply the full series maybe some of the other users was
already taken care of.

	Sam

> Signed-off-by: Daniel Vetter <daniel.vetter@...el.com>
> Cc: Daniel Vetter <daniel.vetter@...ll.ch>
> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
> Cc: Hans de Goede <hdegoede@...hat.com>
> Cc: Yisheng Xie <ysxie@...mail.com>
> Cc: "Michał Mirosław" <mirq-linux@...e.qmqm.pl>
> Cc: Peter Rosin <peda@...ntia.se>
> Cc: Mikulas Patocka <mpatocka@...hat.com>
> Cc: Rob Clark <robdclark@...il.com>
> ---
>  drivers/video/fbdev/core/fbcon.c   | 5 ++---
>  drivers/video/fbdev/core/fbmem.c   | 3 ---
>  drivers/video/fbdev/core/fbsysfs.c | 2 --
>  3 files changed, 2 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
> index f85d794a3bee..c1a7476e980f 100644
> --- a/drivers/video/fbdev/core/fbcon.c
> +++ b/drivers/video/fbdev/core/fbcon.c
> @@ -2382,9 +2382,8 @@ static int fbcon_blank(struct vc_data *vc, int blank, int mode_switch)
>  			fbcon_cursor(vc, blank ? CM_ERASE : CM_DRAW);
>  			ops->cursor_flash = (!blank);
>  
> -			if (!(info->flags & FBINFO_MISC_USEREVENT))
> -				if (fb_blank(info, blank))
> -					fbcon_generic_blank(vc, info, blank);
> +			if (fb_blank(info, blank))
> +				fbcon_generic_blank(vc, info, blank);
>  		}
>  
>  		if (!blank)
> diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
> index 7f95c7e80155..65a075ccac4a 100644
> --- a/drivers/video/fbdev/core/fbmem.c
> +++ b/drivers/video/fbdev/core/fbmem.c
> @@ -1194,10 +1194,7 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
>  	case FBIOBLANK:
>  		console_lock();
>  		lock_fb_info(info);
> -		info->flags |= FBINFO_MISC_USEREVENT;
>  		ret = fb_blank(info, arg);
> -		info->flags &= ~FBINFO_MISC_USEREVENT;
> -
>  		/* might again call into fb_blank */
>  		fbcon_fb_blanked(info, arg);
>  		unlock_fb_info(info);
> diff --git a/drivers/video/fbdev/core/fbsysfs.c b/drivers/video/fbdev/core/fbsysfs.c
> index 252d4f52d2a5..882b471d619e 100644
> --- a/drivers/video/fbdev/core/fbsysfs.c
> +++ b/drivers/video/fbdev/core/fbsysfs.c
> @@ -310,9 +310,7 @@ static ssize_t store_blank(struct device *device,
>  
>  	arg = simple_strtoul(buf, &last, 0);
>  	console_lock();
> -	fb_info->flags |= FBINFO_MISC_USEREVENT;
>  	err = fb_blank(fb_info, arg);
> -	fb_info->flags &= ~FBINFO_MISC_USEREVENT;
>  	/* might again call into fb_blank */
>  	fbcon_fb_blanked(fb_info, arg);
>  	console_unlock();
> -- 
> 2.20.1
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@...ts.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

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