It was broken somewhere between b00d209241ff and 3541833fd1f2. [ 0.000000] cannot allocate crashkernel (size:0x20000000) Where a good one looks like this, [ 0.000000] crashkernel reserved: 0x0000000008600000 - 0x0000000028600000 (512 MB) Some commits look more suspicious than others. mm: add mm_pxd_folded checks to pgtable_bytes accounting functions mm: introduce mm_[p4d|pud|pmd]_folded mm: make the __PAGETABLE_PxD_FOLDED defines non-empty # diff -u ../iomem.good.txt ../iomem.bad.txt --- ../iomem.good.txt 2018-11-10 22:28:20.092614398 -0500 +++ ../iomem.bad.txt 2018-11-10 20:39:54.930294479 -0500 @@ -1,9 +1,8 @@ 00000000-3965ffff : System RAM 00080000-018cffff : Kernel code - 018d0000-020affff : reserved - 020b0000-045affff : Kernel data - 08600000-285fffff : Crash kernel - 28730000-2d5affff : reserved + 018d0000-0762ffff : reserved + 07630000-09b2ffff : Kernel data + 231b0000-2802ffff : reserved 30ec0000-30ecffff : reserved 35660000-3965ffff : reserved 39660000-396fffff : reserved @@ -127,7 +126,7 @@ 7c5200000-7c520ffff : 0004:48:00.0 1040000000-17fbffffff : System RAM 13fbfd0000-13fdfdffff : reserved - 16fba80000-17fbfdffff : reserved + 16fafd0000-17fbfdffff : reserved 17fbfe0000-17fbffffff : reserved 1800000000-1ffbffffff : System RAM 1bfbff0000-1bfdfeffff : reserved The memory map looks like this, [ 0.000000] ACPI: Early table checksum verification disabled [ 0.000000] ACPI: RSDP 0x00000000398D0014 000024 (v02 HISI ) [ 0.000000] ACPI: XSDT 0x00000000398C00E8 000064 (v01 HISI HIP07 00000000 01000013) [ 0.000000] ACPI: FACP 0x0000000039770000 000114 (v06 HISI HIP07 00000000 INTL 20151124) [ 0.000000] ACPI: DSDT 0x0000000039730000 00691A (v02 HISI HIP07 00000000 INTL 20170728) [ 0.000000] ACPI: MCFG 0x00000000397C0000 0000AC (v01 HISI HIP07 00000000 INTL 20151124) [ 0.000000] ACPI: SLIT 0x00000000397B0000 00003C (v01 HISI HIP07 00000000 INTL 20151124) [ 0.000000] ACPI: SRAT 0x00000000397A0000 000578 (v03 HISI HIP07 00000000 INTL 20151124) [ 0.000000] ACPI: DBG2 0x0000000039790000 00005A (v00 HISI HIP07 00000000 INTL 20151124) [ 0.000000] ACPI: GTDT 0x0000000039760000 00007C (v02 HISI HIP07 00000000 INTL 20151124) [ 0.000000] ACPI: APIC 0x0000000039750000 0014E4 (v04 HISI HIP07 00000000 INTL 20151124) [ 0.000000] ACPI: IORT 0x0000000039740000 000554 (v00 HISI HIP07 00000000 INTL 20170728) [ 0.000000] ACPI: SRAT: Node 0 PXM 0 [mem 0x00000000-0x3fffffff] [ 0.000000] ACPI: SRAT: Node 1 PXM 1 [mem 0x1800000000-0x1fffffffff] [ 0.000000] ACPI: SRAT: Node 0 PXM 0 [mem 0x1000000000-0x17ffffffff] [ 0.000000] ACPI: SRAT: Node 3 PXM 3 [mem 0x9000000000-0x97ffffffff] [ 0.000000] ACPI: SRAT: Node 2 PXM 2 [mem 0x8800000000-0x8fffffffff] [ 0.000000] NUMA: NODE_DATA [mem 0x17fbffe5c0-0x17fbffffff] [ 0.000000] NUMA: NODE_DATA [mem 0x1ffbffe5c0-0x1ffbffffff] [ 0.000000] NUMA: NODE_DATA [mem 0x8ffbffe5c0-0x8ffbffffff] [ 0.000000] NUMA: NODE_DATA [mem 0x97fadce5c0-0x97fadcffff] [ 0.000000] Zone ranges: [ 0.000000] DMA32 [mem 0x0000000000000000-0x00000000ffffffff] [ 0.000000] Normal [mem 0x0000000100000000-0x00000097fbffffff] [ 0.000000] Movable zone start for each node [ 0.000000] Early memory node ranges [ 0.000000] node 0: [mem 0x0000000000000000-0x000000003965ffff] [ 0.000000] node 0: [mem 0x0000000039660000-0x00000000396fffff] [ 0.000000] node 0: [mem 0x0000000039700000-0x000000003977ffff] [ 0.000000] node 0: [mem 0x0000000039780000-0x000000003978ffff] [ 0.000000] node 0: [mem 0x0000000039790000-0x00000000397cffff] [ 0.000000] node 0: [mem 0x00000000397d0000-0x00000000398bffff] [ 0.000000] node 0: [mem 0x00000000398c0000-0x00000000398dffff] [ 0.000000] node 0: [mem 0x00000000398e0000-0x0000000039d5ffff] [ 0.000000] node 0: [mem 0x0000000039d60000-0x000000003ed4ffff] [ 0.000000] node 0: [mem 0x000000003ed50000-0x000000003ed7ffff] [ 0.000000] node 0: [mem 0x000000003ed80000-0x000000003fbfffff] [ 0.000000] node 0: [mem 0x0000001040000000-0x00000017fbffffff] [ 0.000000] node 1: [mem 0x0000001800000000-0x0000001ffbffffff] [ 0.000000] node 2: [mem 0x0000008800000000-0x0000008ffbffffff] [ 0.000000] node 3: [mem 0x0000009000000000-0x00000097fbffffff]