From a1ad1cc9704f64c169261a76e1aee1cf1ae51832 Mon Sep 17 00:00:00 2001 From: Grzegorz Halat Date: Fri, 26 Apr 2019 16:59:46 +0200 Subject: vt/fbcon: deinitialize resources in visual_init() after failed memory allocation After memory allocation failure vc_allocate() doesn't clean up data which has been initialized in visual_init(). In case of fbcon this leads to divide-by-0 in fbcon_init() on next open of the same tty. memory allocation in vc_allocate() may fail here: 1097: vc->vc_screenbuf = kzalloc(vc->vc_screenbuf_size, GFP_KERNEL); on next open() fbcon_init() skips vc_font.data initialization: 1088: if (!p->fontdata) { division by zero in fbcon_init() happens here: 1149: new_cols /= vc->vc_font.width; Additional check is needed in fbcon_deinit() to prevent usage of uninitialized vc_screenbuf: 1251: if (vc->vc_hi_font_mask && vc->vc_screenbuf) 1252: set_vc_hi_font(vc, false); Crash: #6 [ffffc90001eafa60] divide_error at ffffffff81a00be4 [exception RIP: fbcon_init+463] RIP: ffffffff814b860f RSP: ffffc90001eafb18 RFLAGS: 00010246 ... #7 [ffffc90001eafb60] visual_init at ffffffff8154c36e #8 [ffffc90001eafb80] vc_allocate at ffffffff8154f53c #9 [ffffc90001eafbc8] con_install at ffffffff8154f624 ... Signed-off-by: Grzegorz Halat Reviewed-by: Oleksandr Natalenko Acked-by: Bartlomiej Zolnierkiewicz Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/video/fbdev/core/fbcon.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/video') diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c index 786f9aab55df..a9c69ae30878 100644 --- a/drivers/video/fbdev/core/fbcon.c +++ b/drivers/video/fbdev/core/fbcon.c @@ -1248,7 +1248,7 @@ finished: if (free_font) vc->vc_font.data = NULL; - if (vc->vc_hi_font_mask) + if (vc->vc_hi_font_mask && vc->vc_screenbuf) set_vc_hi_font(vc, false); if (!con_is_bound(&fb_con)) -- cgit v1.2.3