Bug 2493717 (CVE-2026-53285) - CVE-2026-53285 kernel: drm/amd/display: Wrap DCN32 phantom-plane allocation in DC_RUN_WITH_PREEMPTION_ENABLED
Summary: CVE-2026-53285 kernel: drm/amd/display: Wrap DCN32 phantom-plane allocation i...
Keywords:
Status: NEW
Alias: CVE-2026-53285
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
low
low
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-06-26 21:02 UTC by OSIDB Bzimport
Modified: 2026-06-29 10:09 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
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Description OSIDB Bzimport 2026-06-26 21:02:47 UTC
In the Linux kernel, the following vulnerability has been resolved:

drm/amd/display: Wrap DCN32 phantom-plane allocation in DC_RUN_WITH_PREEMPTION_ENABLED

[Why]
dcn32_validate_bandwidth() wraps dcn32_internal_validate_bw() with
DC_FP_START()/DC_FP_END(). In x86 non-RT, DC_FP_START takes fpregs_lock(),
which disables local softirqs.

The DML1 path through dcn32_enable_phantom_plane() calls kvzalloc() to
allocate ~335 KiB for dc_plane_state. This triggers the vmalloc path,
which calls BUG_ON(in_interrupt()) because it's invoked within the
FPU-enabled (softirq disabled) region, leading to a kernel crash.

[How]
Wrap the dc_state_create_phantom_plane() call with the
DC_RUN_WITH_PREEMPTION_ENABLED() macro to allow preemption during
this memory allocation.

(cherry picked from commit 885ccbef7b94a8b38f69c4211c679021aa27ad11)

Comment 1 Mauro Matteo Cascella 2026-06-29 10:02:51 UTC
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026062615-CVE-2026-53285-c33f@gregkh/T


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