[PATCH v2 0/2] fbdev: fix mode sysfs lifetime and bounds issues

[Melbin K Mathew <mlbnkm1@gmail.com>]

This v2 addresses the remaining fbdev mode sysfs lifetime issues noted
during review.

Patch 1 bounds mode sysfs output so show_modes() cannot advance the
sysfs buffer offset past PAGE_SIZE. mode_string() is given a size
parameter and switched to scnprintf().

Patch 2 serializes mode sysfs access with lock_fb_info(), including
store_mode(), show_mode(), and show_modes(), so these paths cannot race
with store_modes() while it replaces and frees the old modelist.

Changes in v2:
- Add bounds handling for mode_string()/show_modes().
- Extend locking to store_mode() via activate_locked().
- Keep show_mode() using a stack copy after dropping lock_fb_info().
- Avoid overclaiming unprivileged impact in the commit text.


Melbin K Mathew (2):
  fbdev: bound mode sysfs output to the sysfs buffer
  fbdev: serialize mode sysfs access with lock_fb_info()

 drivers/video/fbdev/core/fbsysfs.c | 59 ++++++++++++++++++++++++------
 1 file changed, 47 insertions(+), 12 deletions(-)

-- 
2.39.5