I have an ARM crash dump where the page tables have been corrupted. crash segfaults while reading it because of a stack overflow due to recursion in the page table read core: readmem: e2efcde0, KVADDR, "module unwind table", 24, (ROE), 8600bc0> addr: e2efcde0 paddr: 22efcde0 cnt: 24 <readmem: bf006550, KVADDR, "module unwind index table", 8, (ROE), 9ccab28> <readmem: c0004000, KVADDR, "pgd page", 16384, (FOE), 91c18e8> addr: c0004000 paddr: 4000 cnt: 4096 addr: c0005000 paddr: 5000 cnt: 4096 addr: c0006000 paddr: 6000 cnt: 4096 addr: c0007000 paddr: 7000 cnt: 4096 <readmem: ed2d3000, KVADDR, "page table", 4096, (FOE), 91c58f0> <readmem: ed2d3000, KVADDR, "page table", 4096, (FOE), 91c58f0> <readmem: ed2d3000, KVADDR, "page table", 4096, (FOE), 91c58f0> <readmem: ed2d3000, KVADDR, "page table", 4096, (FOE), 91c58f0> <readmem: ed2d3000, KVADDR, "page table", 4096, (FOE), 91c58f0> <readmem: ed2d3000, KVADDR, "page table", 4096, (FOE), 91c58f0> etc till segfault The problem appears to be that the ARM code is attempting to PTOV() the physical address found in the page table and readmem() it as a KVADDR instead of just directly reading it as a PHYSADDR. Patch below. Rabin diff --git a/arm.c b/arm.c index 5eb5649..4ca2fcd 100644 --- a/arm.c +++ b/arm.c @@ -979,9 +979,9 @@ arm_vtop(ulong vaddr, ulong *pgd, physaddr_t *paddr, int verbose) /* * pte_offset_map(pmd, vaddr) */ - page_table = (ulong *)PTOV(pmd_page_addr(pmd_pte)) + PTE_OFFSET(vaddr); + page_table = pmd_page_addr(pmd_pte) + PTE_OFFSET(vaddr); - FILL_PTBL(PAGEBASE(page_table), KVADDR, PAGESIZE()); + FILL_PTBL(PAGEBASE(page_table), PHYSADDR, PAGESIZE()); pte = ULONG(machdep->ptbl + PAGEOFFSET(page_table)); if (verbose) {