iommu/tegra241-cmdqv: Synchronize the error ISR against VINTF (de)init

Summary

In the Linux kernel, the following vulnerability has been resolved: iommu/tegra241-cmdqv: Synchronize the error ISR against VINTF (de)init A user VINTF is torn down by tegra241_cmdqv_deinit_vintf(), which runs from the destroy callback and from the init-failure unwind in the alloc handler. It clears the cmdqv->vintfs[] slot and lets the iommufd core free it, but nothing serializes that against the error interrupt: tegra241_cmdqv_isr() reads cmdqv->vintfs[idx] and dereferences the vintf. A concurrent error can make the ISR read a slot mid-clear (a NULL deref) or use a vintf which is about to be freed (a use-after-free). deinit_vintf() also returns idx to the IDA before clearing the slot, so a concurrent create that reuses idx can publish its new vintf into the slot, only for this teardown to erase it again with the stale NULL store. On the other end, tegra241_cmdqv_init_vintf() publishes a new vintf with a plain store to the cmdqv->vintfs[] slot, and the ISR dereferences fields of a published vintf such as vintf->base. A plain store gives no ordering on a weakly-ordered CPU, and a stale VINTF_ERR_MAP bit on a reused idx can make the ISR pick a vintf the moment it is published, before its fields are set or tegra241_vintf_hw_init() runs. The cmdqv->vintfs[0] slot stays NULL until tegra241_cmdqv_init_structures() first creates VINTF0, so the slot 0 read needs the same NULL check. Publish every slot with an smp_store_release(), and read each slot in the ISR with an smp_load_acquire() under a NULL check, so the ISR always sees a fully built vintf or NULL. Also make deinit_vintf() clear the slot, and synchronize_irq() prior to returning idx to the IDA, so no vintf is freed under a running handler and no reused idx is clobbered.

Timeline

1. Sep 17, 2026, 4:09 PM UTCCVE published
2. Oct 19, 2026, 9:03 AM UTCRecord last updated

Affected versions

• Linux Linux

  From 4dc0d12474f9d4833c3dd96b73d61e406d3f5dc7 · fixed in bcb82407633c3008362ad927699d985ee4981557; From 4dc0d12474f9d4833c3dd96b73d61e406d3f5dc7 · fixed in f3ef4abc271a1d3d7b6715879e149c286dc8aae7; From 4dc0d12474f9d4833c3dd96b73d61e406d3f5dc7 · fixed in a491be376abd1c80a314cdd658632c85cd660b73

• Linux Linux

  6.17

• KernelLinux

  From 6.17.0 · fixed in 6.18.52; From 6.19.0 · fixed in 7.2.6

References 3