CVE-2026-90426iommu/tegra241-cmdqv: Free the error IRQ before tearing down VINTFs

Official description

In the Linux kernel, the following vulnerability has been resolved: iommu/tegra241-cmdqv: Free the error IRQ before tearing down VINTFs tegra241_cmdqv_remove() tears each VINTF down first, then calls free_irq(). Tearing a VINTF down frees vintf0 and clears cmdqv->vintfs[0]. An error in that window makes tegra241_cmdqv_isr() read the stale slot and hand it to tegra241_vintf0_handle_error(), which dereferences a NULL or freed pointer. Free the IRQ before tearing the VINTFs down. free_irq() waits for in-flight handlers to finish and blocks new ones, so no ISR can observe a VINTF as it is torn down. Note: a user-owned VINTF (viommu) could outlive this teardown, which unmaps cmdqv->base and frees cmdqv->vintfs, so a later viommu close then touches freed memory. This is neither introduced nor fixed here: a physical IOMMU is not a pluggable device, so iommufd by design holds no reference on the one behind a viommu, and this teardown is not expected while that viommu is still alive.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/076a4f5b1fc2016b973a12bc2ebb9b730e5e1e48
• https://git.kernel.org/stable/c/735698e81f798b4c02dcb6291ffbdd1b962c8c66
• https://git.kernel.org/stable/c/421f5ab135cd4a1353891e5bf2602cfc3c01afc7
• https://git.kernel.org/stable/c/61f0d437988e5730b04442f6a7d30a9907339f2a