CVE-2026-90430iommu/tegra241-cmdqv: Publish an LVCMDQ only after it is fully initialized

Official description

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 packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/d5ec248ee1c79354979c23f7f390e856e9535651
• https://git.kernel.org/stable/c/792f720fc23fe5bd6508d40ed73ae739debd6dcb
• https://git.kernel.org/stable/c/b4535b403d6bf9bcc24dbd62096711329b9c612c
• https://git.kernel.org/stable/c/cbc41aacd49e695338940196e7084770365e1b68