On Wed, Nov 07, 2018 at 03:16:06PM +0100, Ard Biesheuvel wrote: > Bhupesh reports that having numerous memblock reservations at early > boot may result in the following crash: > > Unable to handle kernel paging request at virtual address ffff80003ffe0000 > ... > Call trace: > __memcpy+0x110/0x180 > memblock_add_range+0x134/0x2e8 > memblock_reserve+0x70/0xb8 > memblock_alloc_base_nid+0x6c/0x88 > __memblock_alloc_base+0x3c/0x4c > memblock_alloc_base+0x28/0x4c > memblock_alloc+0x2c/0x38 > early_pgtable_alloc+0x20/0xb0 > paging_init+0x28/0x7f8 > > This is caused by the fact that we permit memblock resizing before the > linear mapping is up, and so the memblock_reserved() array is moved > into memory that is not mapped yet. > > So let's ensure that this crash can no longer occur, by deferring to > call to memblock_allow_resize() to after the linear mapping has been > created. > > Reported-by: Bhupesh Sharma <bhsharma@xxxxxxxxxx> > Acked-by: Will Deacon <will.deacon@xxxxxxx> > Tested-by: Marc Zyngier <marc.zyngier@xxxxxxx> > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> I missed this patch (wasn't cc'ed) but Will pinged me on IRC, so queued for 4.20. Thanks. -- Catalin
