mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-27 19:29:37 +00:00
vgacon: Propagate console boot parameters before calling `vc_resize'
commit3dfac26e2e
upstream. Fix a division by zero in `vgacon_resize' with a backtrace like: vgacon_resize vc_do_resize vgacon_init do_bind_con_driver do_unbind_con_driver fbcon_fb_unbind do_unregister_framebuffer do_register_framebuffer register_framebuffer __drm_fb_helper_initial_config_and_unlock drm_helper_hpd_irq_event dw_hdmi_irq irq_thread kthread caused by `c->vc_cell_height' not having been initialized. This has only started to trigger with commit860dafa902
("vt: Fix character height handling with VT_RESIZEX"), however the ultimate offender is commit50ec42edd9
("[PATCH] Detaching fbcon: fix vgacon to allow retaking of the console"). Said commit has added a call to `vc_resize' whenever `vgacon_init' is called with the `init' argument set to 0, which did not happen before. And the call is made before a key vgacon boot parameter retrieved in `vgacon_startup' has been propagated in `vgacon_init' for `vc_resize' to use to the console structure being worked on. Previously the parameter was `c->vc_font.height' and now it is `c->vc_cell_height'. In this particular scenario the registration of fbcon has failed and vt resorts to vgacon. Now fbcon does have initialized `c->vc_font.height' somehow, unlike `c->vc_cell_height', which is why this code did not crash before, but either way the boot parameters should have been copied to the console structure ahead of the call to `vc_resize' rather than afterwards, so that first the call has a chance to use them and second they do not change the console structure to something possibly different from what was used by `vc_resize'. Move the propagation of the vgacon boot parameters ahead of the call to `vc_resize' then. Adjust the comment accordingly. Fixes:50ec42edd9
("[PATCH] Detaching fbcon: fix vgacon to allow retaking of the console") Cc: stable@vger.kernel.org # v2.6.18+ Reported-by: Wim Osterholt <wim@djo.tudelft.nl> Reported-by: Pavel V. Panteleev <panteleev_p@mcst.ru> Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk> Link: https://lore.kernel.org/r/alpine.DEB.2.21.2110252317110.58149@angie.orcam.me.uk Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
a429446862
commit
caedb12c77
1 changed files with 9 additions and 5 deletions
|
@ -370,11 +370,17 @@ static void vgacon_init(struct vc_data *c, int init)
|
|||
struct uni_pagedir *p;
|
||||
|
||||
/*
|
||||
* We cannot be loaded as a module, therefore init is always 1,
|
||||
* but vgacon_init can be called more than once, and init will
|
||||
* not be 1.
|
||||
* We cannot be loaded as a module, therefore init will be 1
|
||||
* if we are the default console, however if we are a fallback
|
||||
* console, for example if fbcon has failed registration, then
|
||||
* init will be 0, so we need to make sure our boot parameters
|
||||
* have been copied to the console structure for vgacon_resize
|
||||
* ultimately called by vc_resize. Any subsequent calls to
|
||||
* vgacon_init init will have init set to 0 too.
|
||||
*/
|
||||
c->vc_can_do_color = vga_can_do_color;
|
||||
c->vc_scan_lines = vga_scan_lines;
|
||||
c->vc_font.height = c->vc_cell_height = vga_video_font_height;
|
||||
|
||||
/* set dimensions manually if init != 0 since vc_resize() will fail */
|
||||
if (init) {
|
||||
|
@ -383,8 +389,6 @@ static void vgacon_init(struct vc_data *c, int init)
|
|||
} else
|
||||
vc_resize(c, vga_video_num_columns, vga_video_num_lines);
|
||||
|
||||
c->vc_scan_lines = vga_scan_lines;
|
||||
c->vc_font.height = c->vc_cell_height = vga_video_font_height;
|
||||
c->vc_complement_mask = 0x7700;
|
||||
if (vga_512_chars)
|
||||
c->vc_hi_font_mask = 0x0800;
|
||||
|
|
Loading…
Reference in a new issue