All of lore.kernel.org
 help / color / mirror / Atom feed
* [PATCH] fix NULL pointer deference crash
@ 2021-03-31 16:34 ` Hassan Shahbazi
  0 siblings, 0 replies; 13+ messages in thread
From: Hassan Shahbazi @ 2021-03-31 16:34 UTC (permalink / raw)
  To: gregkh, daniel.vetter, jirislaby, yepeilin.cs
  Cc: linux-fbdev, dri-devel, linux-kernel, Hassan Shahbazi

The patch has fixed a NULL pointer deference crash in hiding the cursor. It 
is verified by syzbot patch tester.

Reported by: syzbot
https://syzkaller.appspot.com/bug?id=defb47bf56e1c14d5687280c7bb91ce7b608b94b

Signed-off-by: Hassan Shahbazi <h.shahbazi.git@gmail.com>
---
 drivers/video/fbdev/core/fbcon.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
index 44a5cd2f54cc..ee252d1c43c6 100644
--- a/drivers/video/fbdev/core/fbcon.c
+++ b/drivers/video/fbdev/core/fbcon.c
@@ -1333,8 +1333,9 @@ static void fbcon_cursor(struct vc_data *vc, int mode)
 
 	ops->cursor_flash = (mode == CM_ERASE) ? 0 : 1;
 
-	ops->cursor(vc, info, mode, get_color(vc, info, c, 1),
-		    get_color(vc, info, c, 0));
+	if (ops && ops->cursor)
+		ops->cursor(vc, info, mode, get_color(vc, info, c, 1),
+				get_color(vc, info, c, 0));
 }
 
 static int scrollback_phys_max = 0;
-- 
2.26.3


^ permalink raw reply related	[flat|nested] 13+ messages in thread
* Re: [PATCH] fix NULL pointer deference crash
@ 2021-03-31 19:29 kernel test robot
  0 siblings, 0 replies; 13+ messages in thread
From: kernel test robot @ 2021-03-31 19:29 UTC (permalink / raw)
  To: kbuild

[-- Attachment #1: Type: text/plain, Size: 4585 bytes --]

CC: kbuild-all(a)lists.01.org
In-Reply-To: <20210331163425.8092-1-h.shahbazi.git@gmail.com>
References: <20210331163425.8092-1-h.shahbazi.git@gmail.com>
TO: Hassan Shahbazi <h.shahbazi.git@gmail.com>
TO: gregkh(a)linuxfoundation.org
TO: daniel.vetter(a)ffwll.ch
TO: jirislaby(a)kernel.org
TO: yepeilin.cs(a)gmail.com
CC: linux-fbdev(a)vger.kernel.org
CC: dri-devel(a)lists.freedesktop.org
CC: linux-kernel(a)vger.kernel.org
CC: Hassan Shahbazi <h.shahbazi.git@gmail.com>

Hi Hassan,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on v5.12-rc5]
[cannot apply to next-20210331]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Hassan-Shahbazi/fix-NULL-pointer-deference-crash/20210401-004543
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 5e46d1b78a03d52306f21f77a4e4a144b6d31486
:::::: branch date: 3 hours ago
:::::: commit date: 3 hours ago
config: x86_64-randconfig-m001-20210330 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

New smatch warnings:
drivers/video/fbdev/core/fbcon.c:1336 fbcon_cursor() warn: variable dereferenced before check 'ops' (see line 1324)

Old smatch warnings:
drivers/video/fbdev/core/fbcon.c:3028 fbcon_get_con2fb_map_ioctl() warn: potential spectre issue 'con2fb_map' [r]

vim +/ops +1336 drivers/video/fbdev/core/fbcon.c

^1da177e4c3f415 drivers/video/console/fbcon.c    Linus Torvalds     2005-04-16  1317  
^1da177e4c3f415 drivers/video/console/fbcon.c    Linus Torvalds     2005-04-16  1318  static void fbcon_cursor(struct vc_data *vc, int mode)
^1da177e4c3f415 drivers/video/console/fbcon.c    Linus Torvalds     2005-04-16  1319  {
^1da177e4c3f415 drivers/video/console/fbcon.c    Linus Torvalds     2005-04-16  1320  	struct fb_info *info = registered_fb[con2fb_map[vc->vc_num]];
^1da177e4c3f415 drivers/video/console/fbcon.c    Linus Torvalds     2005-04-16  1321  	struct fbcon_ops *ops = info->fbcon_par;
^1da177e4c3f415 drivers/video/console/fbcon.c    Linus Torvalds     2005-04-16  1322   	int c = scr_readw((u16 *) vc->vc_pos);
^1da177e4c3f415 drivers/video/console/fbcon.c    Linus Torvalds     2005-04-16  1323  
2a17d7e80f1df44 drivers/video/console/fbcon.c    Scot Doyle         2015-08-04 @1324  	ops->cur_blink_jiffies = msecs_to_jiffies(vc->vc_cur_blink_ms);
2a17d7e80f1df44 drivers/video/console/fbcon.c    Scot Doyle         2015-08-04  1325  
d1e2306681ad3cb drivers/video/console/fbcon.c    Michal Januszewski 2007-05-08  1326  	if (fbcon_is_inactive(vc, info) || vc->vc_deccm != 1)
^1da177e4c3f415 drivers/video/console/fbcon.c    Linus Torvalds     2005-04-16  1327  		return;
^1da177e4c3f415 drivers/video/console/fbcon.c    Linus Torvalds     2005-04-16  1328  
c0e4b3ad67997a6 drivers/video/fbdev/core/fbcon.c Jiri Slaby         2020-06-15  1329  	if (vc->vc_cursor_type & CUR_SW)
acba9cd01974353 drivers/video/console/fbcon.c    Antonino A. Daplas 2007-07-17  1330  		fbcon_del_cursor_timer(info);
a5edce421848442 drivers/video/console/fbcon.c    Thierry Reding     2015-05-21  1331  	else
acba9cd01974353 drivers/video/console/fbcon.c    Antonino A. Daplas 2007-07-17  1332  		fbcon_add_cursor_timer(info);
acba9cd01974353 drivers/video/console/fbcon.c    Antonino A. Daplas 2007-07-17  1333  
^1da177e4c3f415 drivers/video/console/fbcon.c    Linus Torvalds     2005-04-16  1334  	ops->cursor_flash = (mode == CM_ERASE) ? 0 : 1;
^1da177e4c3f415 drivers/video/console/fbcon.c    Linus Torvalds     2005-04-16  1335  
1d73453653c6d4f drivers/video/fbdev/core/fbcon.c Hassan Shahbazi    2021-03-31 @1336  	if (ops && ops->cursor)
06a0df4d1b8b13b drivers/video/fbdev/core/fbcon.c Linus Torvalds     2020-09-08  1337  		ops->cursor(vc, info, mode, get_color(vc, info, c, 1),
^1da177e4c3f415 drivers/video/console/fbcon.c    Linus Torvalds     2005-04-16  1338  				get_color(vc, info, c, 0));
^1da177e4c3f415 drivers/video/console/fbcon.c    Linus Torvalds     2005-04-16  1339  }
^1da177e4c3f415 drivers/video/console/fbcon.c    Linus Torvalds     2005-04-16  1340  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

[-- Attachment #2: config.gz --]
[-- Type: application/gzip, Size: 45368 bytes --]

^ permalink raw reply	[flat|nested] 13+ messages in thread

end of thread, other threads:[~2021-04-01  6:55 UTC | newest]

Thread overview: 13+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2021-03-31 16:34 [PATCH] fix NULL pointer deference crash Hassan Shahbazi
2021-03-31 16:34 ` Hassan Shahbazi
2021-03-31 17:32 ` Greg KH
2021-03-31 17:32   ` Greg KH
2021-04-01  6:21   ` Hassan Shahbazi
2021-04-01  6:21     ` Hassan Shahbazi
2021-04-01  6:54     ` Greg KH
2021-04-01  6:54       ` Greg KH
2021-03-31 20:02 ` Dan Carpenter
2021-03-31 20:02   ` Dan Carpenter
2021-03-31 20:02   ` Dan Carpenter
2021-03-31 20:02   ` Dan Carpenter
  -- strict thread matches above, loose matches on Subject: below --
2021-03-31 19:29 kernel test robot

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.