In the Linux kernel, the following vulnerability has been resolved:
drm/fb-helper: defer setup when fbdev_probe() fails, not just on -EAGAIN
__drm_fb_helper_initial_config_and_unlock() calls
drm_client_modeset_probe() first, which already fills in each
mode_set->mode/num_connectors for every connected output, and only
afterwards calls drm_fb_helper_single_fb_probe() to create
fb_helper->fb and wire it into those mode_sets via
drm_setup_crtcs_fb().
If drm_fb_helper_single_fb_probe() fails with anything other than
-EAGAIN (e.g. dev->driver->fbdev_probe() itself fails), the function
bails out before drm_setup_crtcs_fb() runs and before setting
fb_helper->deferred_setup. The client is left with mode_sets that
have a mode and connectors but mode_set->fb == NULL, and nothing
marks this fb_helper as needing a retry.
__drm_fb_helper_restore_fbdev_mode_unlocked() only skips committing
when fb_helper->deferred_setup is set, so a later .restore() call
(drm_lastclose() on process exit, in this report) commits the stale
mode_set through drm_client_modeset_commit() ->
drm_client_modeset_commit_atomic() -> __drm_atomic_helper_set_config(),
which hits WARN_ON(!set->fb).
Mark fb_helper->deferred_setup on any drm_fb_helper_single_fb_probe()
failure, not just -EAGAIN, so restore keeps skipping the commit until
a later hotplug event successfully re-probes and re-populates
mode_set->fb. The real error code is still returned to the caller
unchanged.
drm/fb-helper: defer setup when fbdev_probe() fails, not just on -EAGAIN
__drm_fb_helper_initial_config_and_unlock() calls
drm_client_modeset_probe() first, which already fills in each
mode_set->mode/num_connectors for every connected output, and only
afterwards calls drm_fb_helper_single_fb_probe() to create
fb_helper->fb and wire it into those mode_sets via
drm_setup_crtcs_fb().
If drm_fb_helper_single_fb_probe() fails with anything other than
-EAGAIN (e.g. dev->driver->fbdev_probe() itself fails), the function
bails out before drm_setup_crtcs_fb() runs and before setting
fb_helper->deferred_setup. The client is left with mode_sets that
have a mode and connectors but mode_set->fb == NULL, and nothing
marks this fb_helper as needing a retry.
__drm_fb_helper_restore_fbdev_mode_unlocked() only skips committing
when fb_helper->deferred_setup is set, so a later .restore() call
(drm_lastclose() on process exit, in this report) commits the stale
mode_set through drm_client_modeset_commit() ->
drm_client_modeset_commit_atomic() -> __drm_atomic_helper_set_config(),
which hits WARN_ON(!set->fb).
Mark fb_helper->deferred_setup on any drm_fb_helper_single_fb_probe()
failure, not just -EAGAIN, so restore keeps skipping the commit until
a later hotplug event successfully re-probes and re-populates
mode_set->fb. The real error code is still returned to the caller
unchanged.
Metrics
Affected Vendors & Products
No data.
No data.
OpenCVE Enrichment is a feature of OpenCVE that uses AI to automatically link vendors and products to CVEs. Learn more on GitHub.
No data.
Advisories
No advisories yet.
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Fri, 23 Oct 2026 15:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-390 |
Fri, 23 Oct 2026 12:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: drm/fb-helper: defer setup when fbdev_probe() fails, not just on -EAGAIN __drm_fb_helper_initial_config_and_unlock() calls drm_client_modeset_probe() first, which already fills in each mode_set->mode/num_connectors for every connected output, and only afterwards calls drm_fb_helper_single_fb_probe() to create fb_helper->fb and wire it into those mode_sets via drm_setup_crtcs_fb(). If drm_fb_helper_single_fb_probe() fails with anything other than -EAGAIN (e.g. dev->driver->fbdev_probe() itself fails), the function bails out before drm_setup_crtcs_fb() runs and before setting fb_helper->deferred_setup. The client is left with mode_sets that have a mode and connectors but mode_set->fb == NULL, and nothing marks this fb_helper as needing a retry. __drm_fb_helper_restore_fbdev_mode_unlocked() only skips committing when fb_helper->deferred_setup is set, so a later .restore() call (drm_lastclose() on process exit, in this report) commits the stale mode_set through drm_client_modeset_commit() -> drm_client_modeset_commit_atomic() -> __drm_atomic_helper_set_config(), which hits WARN_ON(!set->fb). Mark fb_helper->deferred_setup on any drm_fb_helper_single_fb_probe() failure, not just -EAGAIN, so restore keeps skipping the commit until a later hotplug event successfully re-probes and re-populates mode_set->fb. The real error code is still returned to the caller unchanged. | |
| Title | drm/fb-helper: defer setup when fbdev_probe() fails, not just on -EAGAIN | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
Projects
Sign in to view the affected projects.
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-10-23T12:20:32.381Z
Reserved: 2026-09-25T10:25:14.385Z
Link: CVE-2026-99007
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-10-23T13:17:23.157
Modified: 2026-10-23T13:17:23.157
Link: CVE-2026-99007
Redhat
No data.
OpenCVE Enrichment
Updated: 2026-10-23T15:30:14Z
Weaknesses