kernel/linux.git/drivers/video/console, branch v6.18.21

Revert "vgacon: Add check for vc_origin address range in vgacon_scroll()"

2025-08-02T19:47:33+00:00

This reverts commit 864f9963ec6b4b76d104d595ba28110b87158003. The patch is wrong as it checks vc_origin against vc_screenbuf, while in text mode it should compare against vga_vram_base. As such it broke VGA text scrolling, which can be reproduced like this: (1) boot a kernel that is configured to use text mode VGA-console (2) type commands: ls -l /usr/bin | less -S (3) scroll up/down with cursor-down/up keys Reported-by: Jari Ruusu Cc: stable@vger.kernel.org Cc: Yi Yang Cc: GONG Ruiqi Signed-off-by: Helge Deller

Merge tag 'drm-fixes-2025-06-06' of https://gitlab.freedesktop.org/drm/kernel

2025-06-06T16:26:47+00:00

Pull more drm fixes from Simona Vetter: "Another small batch of drm fixes, this time with a different baseline and hence separate. Drivers: - ivpu: - dma_resv locking - warning fixes - reset failure handling - improve logging - update fw file names - fix cmdqueue unregister - panel-simple: add Evervision VGG644804 Core Changes: - sysfb: screen_info type check - video: screen_info for relocated pci fb - drm/sched: signal fence of killed job - dummycon: deferred takeover fix" * tag 'drm-fixes-2025-06-06' of https://gitlab.freedesktop.org/drm/kernel: sysfb: Fix screen_info type check for VGA video: screen_info: Relocate framebuffers behind PCI bridges accel/ivpu: Fix warning in ivpu_gem_bo_free() accel/ivpu: Trigger device recovery on engine reset/resume failure accel/ivpu: Use dma_resv_lock() instead of a custom mutex drm/panel-simple: fix the warnings for the Evervision VGG644804 accel/ivpu: Reorder Doorbell Unregister and Command Queue Destruction accel/ivpu: Use firmware names from upstream repo accel/ivpu: Improve buffer object logging dummycon: Trigger redraw when switching consoles with deferred takeover drm/scheduler: signal scheduled fence when kill job

vgacon: Add check for vc_origin address range in vgacon_scroll()

2025-05-31T08:24:02+00:00

Our in-house Syzkaller reported the following BUG (twice), which we believed was the same issue with [1]: ================================================================== BUG: KASAN: slab-out-of-bounds in vcs_scr_readw+0xc2/0xd0 drivers/tty/vt/vt.c:4740 Read of size 2 at addr ffff88800f5bef60 by task syz.7.2620/12393 ... Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x72/0xa0 lib/dump_stack.c:106 print_address_description.constprop.0+0x6b/0x3d0 mm/kasan/report.c:364 print_report+0xba/0x280 mm/kasan/report.c:475 kasan_report+0xa9/0xe0 mm/kasan/report.c:588 vcs_scr_readw+0xc2/0xd0 drivers/tty/vt/vt.c:4740 vcs_write_buf_noattr drivers/tty/vt/vc_screen.c:493 [inline] vcs_write+0x586/0x840 drivers/tty/vt/vc_screen.c:690 vfs_write+0x219/0x960 fs/read_write.c:584 ksys_write+0x12e/0x260 fs/read_write.c:639 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x59/0x110 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x78/0xe2 ... Allocated by task 5614: kasan_save_stack+0x20/0x40 mm/kasan/common.c:45 kasan_set_track+0x25/0x30 mm/kasan/common.c:52 ____kasan_kmalloc mm/kasan/common.c:374 [inline] __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:383 kasan_kmalloc include/linux/kasan.h:201 [inline] __do_kmalloc_node mm/slab_common.c:1007 [inline] __kmalloc+0x62/0x140 mm/slab_common.c:1020 kmalloc include/linux/slab.h:604 [inline] kzalloc include/linux/slab.h:721 [inline] vc_do_resize+0x235/0xf40 drivers/tty/vt/vt.c:1193 vgacon_adjust_height+0x2d4/0x350 drivers/video/console/vgacon.c:1007 vgacon_font_set+0x1f7/0x240 drivers/video/console/vgacon.c:1031 con_font_set drivers/tty/vt/vt.c:4628 [inline] con_font_op+0x4da/0xa20 drivers/tty/vt/vt.c:4675 vt_k_ioctl+0xa10/0xb30 drivers/tty/vt/vt_ioctl.c:474 vt_ioctl+0x14c/0x1870 drivers/tty/vt/vt_ioctl.c:752 tty_ioctl+0x655/0x1510 drivers/tty/tty_io.c:2779 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl+0x12d/0x190 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x59/0x110 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x78/0xe2 Last potentially related work creation: kasan_save_stack+0x20/0x40 mm/kasan/common.c:45 __kasan_record_aux_stack+0x94/0xa0 mm/kasan/generic.c:492 __call_rcu_common.constprop.0+0xc3/0xa10 kernel/rcu/tree.c:2713 netlink_release+0x620/0xc20 net/netlink/af_netlink.c:802 __sock_release+0xb5/0x270 net/socket.c:663 sock_close+0x1e/0x30 net/socket.c:1425 __fput+0x408/0xab0 fs/file_table.c:384 __fput_sync+0x4c/0x60 fs/file_table.c:465 __do_sys_close fs/open.c:1580 [inline] __se_sys_close+0x68/0xd0 fs/open.c:1565 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x59/0x110 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x78/0xe2 Second to last potentially related work creation: kasan_save_stack+0x20/0x40 mm/kasan/common.c:45 __kasan_record_aux_stack+0x94/0xa0 mm/kasan/generic.c:492 __call_rcu_common.constprop.0+0xc3/0xa10 kernel/rcu/tree.c:2713 netlink_release+0x620/0xc20 net/netlink/af_netlink.c:802 __sock_release+0xb5/0x270 net/socket.c:663 sock_close+0x1e/0x30 net/socket.c:1425 __fput+0x408/0xab0 fs/file_table.c:384 task_work_run+0x154/0x240 kernel/task_work.c:239 exit_task_work include/linux/task_work.h:45 [inline] do_exit+0x8e5/0x1320 kernel/exit.c:874 do_group_exit+0xcd/0x280 kernel/exit.c:1023 get_signal+0x1675/0x1850 kernel/signal.c:2905 arch_do_signal_or_restart+0x80/0x3b0 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x1b3/0x1e0 kernel/entry/common.c:218 do_syscall_64+0x66/0x110 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x78/0xe2 The buggy address belongs to the object at ffff88800f5be000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 2656 bytes to the right of allocated 1280-byte region [ffff88800f5be000, ffff88800f5be500) ... Memory state around the buggy address: ffff88800f5bee00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88800f5bee80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88800f5bef00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff88800f5bef80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88800f5bf000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ================================================================== By analyzing the vmcore, we found that vc->vc_origin was somehow placed one line prior to vc->vc_screenbuf when vc was in KD_TEXT mode, and further writings to /dev/vcs caused out-of-bounds reads (and writes right after) in vcs_write_buf_noattr(). Our further experiments show that in most cases, vc->vc_origin equals to vga_vram_base when the console is in KD_TEXT mode, and it's around vc->vc_screenbuf for the KD_GRAPHICS mode. But via triggerring a TIOCL_SETVESABLANK ioctl beforehand, we can make vc->vc_origin be around vc->vc_screenbuf while the console is in KD_TEXT mode, and then by writing the special 'ESC M' control sequence to the tty certain times (depends on the value of `vc->state.y - vc->vc_top`), we can eventually move vc->vc_origin prior to vc->vc_screenbuf. Here's the PoC, tested on QEMU: ``` int main() { const int RI_NUM = 10; // should be greater than `vc->state.y - vc->vc_top` int tty_fd, vcs_fd; const char *tty_path = "/dev/tty0"; const char *vcs_path = "/dev/vcs"; const char escape_seq[] = "\x1bM"; // ESC + M const char trigger_seq[] = "Let's trigger an OOB write."; struct vt_sizes vt_size = { 70, 2 }; int blank = TIOCL_BLANKSCREEN; tty_fd = open(tty_path, O_RDWR); char vesa_mode[] = { TIOCL_SETVESABLANK, 1 }; ioctl(tty_fd, TIOCLINUX, vesa_mode); ioctl(tty_fd, TIOCLINUX, &blank); ioctl(tty_fd, VT_RESIZE, &vt_size); for (int i = 0; i < RI_NUM; ++i) write(tty_fd, escape_seq, sizeof(escape_seq) - 1); vcs_fd = open(vcs_path, O_RDWR); write(vcs_fd, trigger_seq, sizeof(trigger_seq)); close(vcs_fd); close(tty_fd); return 0; } ``` To solve this problem, add an address range validation check in vgacon_scroll(), ensuring vc->vc_origin never precedes vc_screenbuf. Reported-by: syzbot+9c09fda97a1a65ea859b@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=9c09fda97a1a65ea859b [1] Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Co-developed-by: Yi Yang Signed-off-by: Yi Yang Signed-off-by: GONG Ruiqi Signed-off-by: Helge Deller

dummycon: Trigger redraw when switching consoles with deferred takeover

2025-05-26T07:35:34+00:00

Signal vt subsystem to redraw console when switching to dummycon with deferred takeover enabled. Makes the console switch to fbcon and displays the available output. With deferred takeover enabled, dummycon acts as the placeholder until the first output to the console happens. At that point, fbcon takes over. If the output happens while dummycon is not active, it cannot inform fbcon. This is the case if the vt subsystem runs in graphics mode. A typical graphical boot starts plymouth, a display manager and a compositor; all while leaving out dummycon. Switching to a text-mode console leaves the console with dummycon even if a getty terminal has been started. Returning true from dummycon's con_switch helper signals the vt subsystem to redraw the screen. If there's output available dummycon's con_putc{s} helpers trigger deferred takeover of fbcon, which sets a display mode and displays the output. If no output is available, dummycon remains active. v2: - make the comment slightly more verbose (Javier) Signed-off-by: Thomas Zimmermann Reported-by: Andrei Borzenkov Closes: https://bugzilla.suse.com/show_bug.cgi?id=1242191 Tested-by: Andrei Borzenkov Acked-by: Javier Martinez Canillas Fixes: 83d83bebf401 ("console/fbcon: Add support for deferred console takeover") Cc: Hans de Goede Cc: linux-fbdev@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: # v4.19+ Link: https://lore.kernel.org/r/20250520071418.8462-1-tzimmermann@suse.de

mdacon: rework dependency list

2025-03-26T21:39:20+00:00

mdacon has roughly the same dependencies as vgacon but expresses them as a negative list instead of a positive list, with the only practical difference being PowerPC/CHRP, which uses vga16fb instead of vgacon. The CONFIG_MDA_CONSOLE description advises to only turn it on when vgacon is also used because MDA/Hercules-only systems should be using vgacon instead, so just change the list to enforce that directly for simplicity. The probing was broken from 2002 to 2008, this improves on the fix that was added then: If vgacon is a loadable module, then mdacon cannot be built-in now, and the list of systems that support vgacon is carried over. Fixes: 0b9cf3aa6b1e ("mdacon messing up default vc's - set default to vc13-16 again") Signed-off-by: Arnd Bergmann Reviewed-by: Thomas Zimmermann Signed-off-by: Helge Deller

dummycon: fix default rows/cols

2025-03-26T21:39:20+00:00

dummycon fails to build on ARM/footbridge when the VGA console is disabled, since I got the dependencies slightly wrong in a previous patch: drivers/video/console/dummycon.c: In function 'dummycon_init': drivers/video/console/dummycon.c:27:25: error: 'CONFIG_DUMMY_CONSOLE_COLUMNS' undeclared (first use in this function); did you mean 'CONFIG_DUMMY_CONSOLE'? 27 | #define DUMMY_COLUMNS CONFIG_DUMMY_CONSOLE_COLUMNS drivers/video/console/dummycon.c:28:25: error: 'CONFIG_DUMMY_CONSOLE_ROWS' undeclared (first use in this function); did you mean 'CONFIG_DUMMY_CONSOLE'? 28 | #define DUMMY_ROWS CONFIG_DUMMY_CONSOLE_ROWS This only showed up after many thousand randconfig builds on Arm, and doesn't matter in practice, but should still be fixed. Address it by using the default row/columns on footbridge after all in that corner case. Fixes: 4293b0925149 ("dummycon: limit Arm console size hack to footbridge") Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202409151512.LML1slol-lkp@intel.com/ Signed-off-by: Arnd Bergmann Reviewed-by: Thomas Zimmermann Signed-off-by: Helge Deller

dummycon: only build module if there are users

2025-03-26T21:39:20+00:00

Dummycon is used as a fallback conswitchp for vgacon and fbcon in the VT code, and there are no references to it if all three are disabled, so just leave it out of the kernel image for configurations without those. Signed-off-by: Arnd Bergmann Reviewed-by: Thomas Zimmermann Signed-off-by: Helge Deller

video: console: add missing MODULE_DESCRIPTION() macros

2024-06-22T07:52:36+00:00

With ARCH=i386, make allmodconfig && make W=1 C=1 reports: WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/video/console/mdacon.o Add the missing invocation of the MODULE_DESCRIPTION() macro to all files which have a MODULE_LICENSE(). This includes three other files which, although they did not produce a warning with the i386 allmodconfig configuration, may cause this warning with other configurations. Signed-off-by: Jeff Johnson Signed-off-by: Helge Deller

tty: vt: change consw::con_set_origin() return type

2024-01-28T02:08:54+00:00

The return value of consw::con_set_origin() is only true/false, meaining if vc->vc_origin is set to vc->vc_screenbuf or not. So switch the type and returned values accordingly. And document the hook. Signed-off-by: "Jiri Slaby (SUSE)" Cc: Helge Deller Cc: linux-fbdev@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Tested-by: Helge Deller # parisc STI console Link: https://lore.kernel.org/r/20240122110401.7289-39-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman

tty: vt: make consw::con_font_default()'s name const

2024-01-28T02:08:54+00:00

It's a name after all and that is not supposed to be changed. So make it const to make this obvious. Signed-off-by: "Jiri Slaby (SUSE)" Cc: "James E.J. Bottomley" Cc: Daniel Vetter Cc: linux-fbdev@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: linux-parisc@vger.kernel.org Tested-by: Helge Deller # parisc STI console Link: https://lore.kernel.org/r/20240122110401.7289-38-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman