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.

Fixes: 918eb5c856f6 ("iommu/arm-smmu-v3: Add in-kernel support for NVIDIA Tegra241 (Grace) CMDQV")
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Will Deacon <will@kernel.org>

0 files changed, 0 insertions, 0 deletions