On Fri, Mar 12, 2021 at 09:36:42AM +0100, Greg Kroah-Hartman wrote:

On Fri, Mar 12, 2021 at 04:14:21PM +0800, Du Cheng wrote:

...

add null-check on function pointer before dereference on ops->cursor

Reported-by: syzbot+b67aaae8d3a927f68d20@syzkaller.appspotmail.com Signed-off-by: Du Cheng ducheng2@gmail.com

---

drivers/video/fbdev/core/fbcon.c | 3 +++ 1 file changed, 3 insertions(+)

diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c index 44a5cd2f54cc..3406067985b1 100644 --- a/drivers/video/fbdev/core/fbcon.c +++ b/drivers/video/fbdev/core/fbcon.c @@ -1333,6 +1333,9 @@ static void fbcon_cursor(struct vc_data *vc, int mode)

ops->cursor_flash = (mode == CM_ERASE) ? 0 : 1;

• if (!ops->cursor)

• return;
  

• ops->cursor(vc, info, mode, get_color(vc, info, c, 1), get_color(vc, info, c, 0));

}

2.27.0

Is this the same issue reported here: https://lore.kernel.org/r/20210307105642.112572-1-h.shahbazi.git@gmail.com

And has syzbot testing shown that this fix does solve the issue?

thanks,

greg k-h

Hi Greg,

I sent both my patch and that of shahbazi to syzbot to see if they resolve the bug by the id b67aaae8d3a927f68d20.

I will keep you posted of the outcomes.

Regards, Du Cheng