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CVE-2026-90430

iommu/tegra241-cmdqv: Publish an LVCMDQ only after it is fully initialized PUBLISHED

Description (CNA)

In the Linux kernel, the following vulnerability has been resolved: iommu/tegra241-cmdqv: Publish an LVCMDQ only after it is fully initialized tegra241_vintf_init_lvcmdq() stores the freshly allocated vcmdq pointer to the vintf->lvcmdqs[] array, before tegra241_vcmdq_alloc_smmu_cmdq() builds the vcmdq->cmdq. The error ISR dereferences that cmdq, so a latched LVCMDQ error (e.g. one inherited across a kexec) firing in this window would make tegra241_vintf0_handle_error() pass the still-zeroed arm_smmu_cmdq down to __arm_smmu_cmdq_skip_err(), dereferencing NULL queue register pointers. Drop the store from tegra241_vintf_init_lvcmdq() and publish the vcmdq at the end of the allocation instead, with an smp_store_release() that pairs with an smp_load_acquire() in the ISR, which can see a fully built LVCMDQ or NULL. The user-owned LVCMDQ allocation moves accordingly, publishing the vcmdq once tegra241_vcmdq_hw_init_user() succeeds, using a plain store since a user VINTF's lvcmdqs[] has no lockless reader -- the error ISR only walks the VINTF0 array.

Affected (CNA)

Vendor / productVersions
Linux / Linuxaffected 918eb5c856f6ce4cf93b4b38e4b5e156905c5943 before d5ec248ee1c79354979c23f7f390e856e9535651; affected 918eb5c856f6ce4cf93b4b38e4b5e156905c5943 before 792f720fc23fe5bd6508d40ed73ae739debd6dcb; affected 918eb5c856f6ce4cf93b4b38e4b5e156905c5943 before b4535b403d6bf9bcc24dbd62096711329b9c612c; affected 918eb5c856f6ce4cf93b4b38e4b5e156905c5943 before cbc41aacd49e695338940196e7084770365e1b68
Linux / Linuxaffected 6.12; unaffected 0 before 6.12; unaffected 6.12.111 through 6.12.*; unaffected 6.18.52 through 6.18.*; unaffected 7.2.6 through 7.2.*; unaffected 7.3 through *

CWE

No CWE identifiers supplied.

References