CVE-2026-98654 - Vulnerability Details

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Link	Providers
https://git.kernel.org/stable/c/63e19ef3ddab806c472748c825f4dc88dcd994e8

Type	Values Removed	Values Added
Description		In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Atomize IRQ register read/modify/write ops [Why] The OTG_GLOBAL_SYNC_STATUS register controls various HW IRQ sources for the output timing generator (OTG). VUPDATE_NO_LOCK is one of them. To enable the IRQ, driver sets the VUPDATE_NO_LOCK_EN bit in the GLOBAL_SYNC_STATUS register. To ack the IRQ after it fires, the driver sets the VUPDATE_NO_LOCK_CLEAR bit in the same GLOBAL_SYNC_STATUS register. The bit sets are done through read/modify/write operations, which are not atomic. Thus, the following race is possible: Thread A: IRQ handler: HW IRQ fires # IRQ disable val = read(GLOBAL_SYNC_STATUS) unset(val, VUPDATE_NO_LOCK_EN) write(val, GLOBAL_SYNC_STATUS) # ACK reads VUPDATE_NO_LOCK_EN unset val1 = read(GLOBAL_SYNC_STATUS) set(val1, VUPDATE_NO_LOCK_CLEAR) # IRQ enable val = read(GLOBAL_SYNC_STATUS) set(val, VUPDATE_NO_LOCK_EN) write(val, GLOBAL_SYNC_STATUS) # BAD! clears VUPDATE_NO_LOCK_EN write(val1, GLOBAL_SYNC_STATUS) Regarding the tagged Fixes: change, it appears the change made this race more likely to occur. Since VUPDATE_NO_LOCK is now the sole IRQ source for vblank handling, a single race on high refresh panels can lead to a time out. [How] The GLOBAL_SYNC_STATUS register is only one example, other IRQ control registers also share the same scheme. On top of GLOBAL_SYNC_STATUS, let's clean up those as well. To keep things simple, Let's atomize the IRQ rmw ops via a single driver-wide spinlock. Due to the small scope of this lock, it is unlikely to cause noticeable overhead on top of all the existing locking within the IRQ set/handle paths. Since DM is responsible for locking, wrap dc_interrupt_set/ack with the spinlock in the new amdgpu_dm_irq_set/ack functions. Migrate/drop all references in DM to dc_interrupt_set/ack to use amdgpu_dm_irq_set/ack instead. (cherry picked from commit 70de0a0216583a53c946155f8c8adedfdca6b4e7)
Title		drm/amd/display: Atomize IRQ register read/modify/write ops
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/63e19ef3ddab806c472748c825f4dc88dcd994e8

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-98654", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.362Z", "datePublished": "2026-10-18T15:20:25.640Z", "dateUpdated": "2026-10-18T15:20:25.640Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-18T15:20:25.640Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/amd/display: Atomize IRQ register read/modify/write ops\n\n[Why]\n\nThe OTG_GLOBAL_SYNC_STATUS register controls various HW IRQ sources for\nthe output timing generator (OTG). VUPDATE_NO_LOCK is one of them.\n\nTo enable the IRQ, driver sets the VUPDATE_NO_LOCK_EN bit in the\nGLOBAL_SYNC_STATUS register.\n\nTo ack the IRQ after it fires, the driver sets the VUPDATE_NO_LOCK_CLEAR\nbit in the same GLOBAL_SYNC_STATUS register.\n\nThe bit sets are done through read/modify/write operations, which are\nnot atomic. Thus, the following race is possible:\n\n Thread A: IRQ handler:\n *HW IRQ fires*\n # IRQ disable\n val = read(GLOBAL_SYNC_STATUS)\n unset(val, VUPDATE_NO_LOCK_EN)\n write(val, GLOBAL_SYNC_STATUS)\n # ACK reads VUPDATE_NO_LOCK_EN unset\n val1 = read(GLOBAL_SYNC_STATUS)\n set(val1, VUPDATE_NO_LOCK_CLEAR)\n # IRQ enable\n val = read(GLOBAL_SYNC_STATUS)\n set(val, VUPDATE_NO_LOCK_EN)\n write(val, GLOBAL_SYNC_STATUS)\n # BAD! clears VUPDATE_NO_LOCK_EN\n write(val1, GLOBAL_SYNC_STATUS)\n\nRegarding the tagged Fixes: change, it appears the change made this race\nmore likely to occur. Since VUPDATE_NO_LOCK is now the sole IRQ source\nfor vblank handling, a single race on high refresh panels can lead to a\ntime out.\n\n[How]\n\nThe GLOBAL_SYNC_STATUS register is only one example, other IRQ control\nregisters also share the same scheme. On top of GLOBAL_SYNC_STATUS,\nlet's clean up those as well.\n\nTo keep things simple, Let's atomize the IRQ rmw ops via a single\ndriver-wide spinlock. Due to the small scope of this lock, it is\nunlikely to cause noticeable overhead on top of all the existing locking\nwithin the IRQ set/handle paths.\n\nSince DM is responsible for locking, wrap dc_interrupt_set/ack with the\nspinlock in the new amdgpu_dm_irq_set/ack functions. Migrate/drop all\nreferences in DM to dc_interrupt_set/ack to use amdgpu_dm_irq_set/ack\ninstead.\n\n(cherry picked from commit 70de0a0216583a53c946155f8c8adedfdca6b4e7)"}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c", "drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h", "drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c", "drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c", "drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_irq.c", "drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_irq.h", "drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_crtc_test.c", "drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c", "drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_irq_test.c"], "versions": [{"version": "c87e6635d2db02c88ae8d09529362da672d34770", "lessThan": "63e19ef3ddab806c472748c825f4dc88dcd994e8", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c", "drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h", "drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c", "drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c", "drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_irq.c", "drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_irq.h", "drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_crtc_test.c", "drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c", "drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_irq_test.c"], "versions": [{"version": "7.3-rc1", "status": "affected"}, {"version": "0", "lessThan": "7.3-rc1", "status": "unaffected", "versionType": "semver"}, {"version": "7.3-rc4", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.3-rc1", "versionEndExcluding": "7.3-rc4"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/63e19ef3ddab806c472748c825f4dc88dcd994e8"}], "title": "drm/amd/display: Atomize IRQ register read/modify/write ops", "x_generator": {"engine": "bippy-1.2.0"}}}}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c", "drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h", "drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c", "drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c", "drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_irq.c", "drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_irq.h", "drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_crtc_test.c", "drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c", "drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_irq_test.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "63e19ef3ddab806c472748c825f4dc88dcd994e8", "status": "affected", "version": "c87e6635d2db02c88ae8d09529362da672d34770", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c", "drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h", "drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c", "drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c", "drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_irq.c", "drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_irq.h", "drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_crtc_test.c", "drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_helpers_test.c", "drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_irq_test.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "7.3-rc1"}, {"lessThan": "7.3-rc1", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.3-rc4", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/amd/display: Atomize IRQ register read/modify/write ops\n\n[Why]\n\nThe OTG_GLOBAL_SYNC_STATUS register controls various HW IRQ sources for\nthe output timing generator (OTG). VUPDATE_NO_LOCK is one of them.\n\nTo enable the IRQ, driver sets the VUPDATE_NO_LOCK_EN bit in the\nGLOBAL_SYNC_STATUS register.\n\nTo ack the IRQ after it fires, the driver sets the VUPDATE_NO_LOCK_CLEAR\nbit in the same GLOBAL_SYNC_STATUS register.\n\nThe bit sets are done through read/modify/write operations, which are\nnot atomic. Thus, the following race is possible:\n\n Thread A: IRQ handler:\n *HW IRQ fires*\n # IRQ disable\n val = read(GLOBAL_SYNC_STATUS)\n unset(val, VUPDATE_NO_LOCK_EN)\n write(val, GLOBAL_SYNC_STATUS)\n # ACK reads VUPDATE_NO_LOCK_EN unset\n val1 = read(GLOBAL_SYNC_STATUS)\n set(val1, VUPDATE_NO_LOCK_CLEAR)\n # IRQ enable\n val = read(GLOBAL_SYNC_STATUS)\n set(val, VUPDATE_NO_LOCK_EN)\n write(val, GLOBAL_SYNC_STATUS)\n # BAD! clears VUPDATE_NO_LOCK_EN\n write(val1, GLOBAL_SYNC_STATUS)\n\nRegarding the tagged Fixes: change, it appears the change made this race\nmore likely to occur. Since VUPDATE_NO_LOCK is now the sole IRQ source\nfor vblank handling, a single race on high refresh panels can lead to a\ntime out.\n\n[How]\n\nThe GLOBAL_SYNC_STATUS register is only one example, other IRQ control\nregisters also share the same scheme. On top of GLOBAL_SYNC_STATUS,\nlet's clean up those as well.\n\nTo keep things simple, Let's atomize the IRQ rmw ops via a single\ndriver-wide spinlock. Due to the small scope of this lock, it is\nunlikely to cause noticeable overhead on top of all the existing locking\nwithin the IRQ set/handle paths.\n\nSince DM is responsible for locking, wrap dc_interrupt_set/ack with the\nspinlock in the new amdgpu_dm_irq_set/ack functions. Migrate/drop all\nreferences in DM to dc_interrupt_set/ack to use amdgpu_dm_irq_set/ack\ninstead.\n\n(cherry picked from commit 70de0a0216583a53c946155f8c8adedfdca6b4e7)"}], "id": "CVE-2026-98654", "lastModified": "2026-10-18T16:17:18.690", "metrics": {}, "published": "2026-10-18T16:17:18.690", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/63e19ef3ddab806c472748c825f4dc88dcd994e8"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

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