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Same for the base address or other addresses as > the page tables, they might be corrupted due to a buggy driver. > My point is that, it is really hard to assume that the previous state > of registers/STE/page-tables were valid or even consistent, when the > kernel crashed and did not transition the state gracefully. Sure, and this mechanism is probably not very useful for debugging these kinds of errors in the SMMU driver. Oh well, that isn't a common source of kernel crashes :) > Similarly for TLBs, the kernel might have panicked in the middle of an > unmap or free domain. (not to mention what that means for RPM where > a device reset with unknown TLBs) TLB is fine. kdump works by carving out a chunk of memory for the future crash kernel. When the kernel boots it ignores all the memory used by the prior kernel. So DMA can keep running into the old kernels memory with no issue. It doesn't matter if the TLBs are inconsistent or not. Jason