linux/drivers/of
Marek Bykowski d5e3050c0f of/fdt: Don't calculate initrd size from DT if start > end
If the properties 'linux,initrd-start' and 'linux,initrd-end' of
the chosen node populated from the bootloader, eg. U-Boot, are so that
start > end, then the phys_initrd_size calculated from end - start is
negative that subsequently gets converted to a high positive value for
being unsigned long long. Then, the memory region with the (invalid)
size is added to the bootmem and attempted being paged in paging_init()
that results in the kernel fault.

For example, on the FVP ARM64 system I'm running, the U-Boot populates
the 'linux,initrd-start' with 8800_0000 and 'linux,initrd-end' with 0.
The phys_initrd_size calculated is then ffff_ffff_7800_0000
(= 0 - 8800_0000 = -8800_0000 + ULLONG_MAX + 1). paging_init() then
attempts to map the address 8800_0000 + ffff_ffff_7800_0000 and oops'es
as below.

It should be stressed, it is generally a fault of the bootloader's with
the kernel relying on it, however we should not allow the bootloader's
misconfiguration to lead to the kernel oops. Not only the kernel should be
bullet proof against it but also finding the root cause of the paging
fault spanning over the bootloader, DT, and kernel may happen is not so
easy.

  Unable to handle kernel paging request at virtual address fffffffefe43c000
  Mem abort info:
    ESR = 0x96000007
    EC = 0x25: DABT (current EL), IL = 32 bits
    SET = 0, FnV = 0
    EA = 0, S1PTW = 0
  Data abort info:
    ISV = 0, ISS = 0x00000007
    CM = 0, WnR = 0
  swapper pgtable: 4k pages, 39-bit VAs, pgdp=0000000080e3d000
  [fffffffefe43c000] pgd=0000000080de9003, pud=0000000080de9003
  Unable to handle kernel paging request at virtual address ffffff8000de9f90
  Mem abort info:
    ESR = 0x96000005
    EC = 0x25: DABT (current EL), IL = 32 bits
    SET = 0, FnV = 0
    EA = 0, S1PTW = 0
  Data abort info:
    ISV = 0, ISS = 0x00000005
    CM = 0, WnR = 0
  swapper pgtable: 4k pages, 39-bit VAs, pgdp=0000000080e3d000
  [ffffff8000de9f90] pgd=0000000000000000, pud=0000000000000000
  Internal error: Oops: 96000005 [#1] PREEMPT SMP
  Modules linked in:
  CPU: 0 PID: 0 Comm: swapper Not tainted 5.4.51-yocto-standard #1
  Hardware name: FVP Base (DT)
  pstate: 60000085 (nZCv daIf -PAN -UAO)
  pc : show_pte+0x12c/0x1b4
  lr : show_pte+0x100/0x1b4
  sp : ffffffc010ce3b30
  x29: ffffffc010ce3b30 x28: ffffffc010ceed80
  x27: fffffffefe43c000 x26: fffffffefe43a028
  x25: 0000000080bf0000 x24: 0000000000000025
  x23: ffffffc010b8d000 x22: ffffffc010e3d000
  x23: ffffffc010b8d000 x22: ffffffc010e3d000
  x21: 0000000080de9000 x20: ffffff7f80000f90
  x19: fffffffefe43c000 x18: 0000000000000030
  x17: 0000000000001400 x16: 0000000000001c00
  x15: ffffffc010cef1b8 x14: ffffffffffffffff
  x13: ffffffc010df1f40 x12: ffffffc010df1b70
  x11: ffffffc010ce3b30 x10: ffffffc010ce3b30
  x9 : 00000000ffffffc8 x8 : 0000000000000000
  x7 : 000000000000000f x6 : ffffffc010df16e8
  x5 : 0000000000000000 x4 : 0000000000000000
  x3 : 00000000ffffffff x2 : 0000000000000000
  x1 : 0000008080000000 x0 : ffffffc010af1d68
  Call trace:
   show_pte+0x12c/0x1b4
   die_kernel_fault+0x54/0x78
   __do_kernel_fault+0x11c/0x128
   do_translation_fault+0x58/0xac
   do_mem_abort+0x50/0xb0
   el1_da+0x1c/0x90
   __create_pgd_mapping+0x348/0x598
   paging_init+0x3f0/0x70d0
   setup_arch+0x2c0/0x5d4
   start_kernel+0x94/0x49c
  Code: 92748eb5 900052a0 9135a000 cb010294 (f8756a96) 

Signed-off-by: Marek Bykowski <marek.bykowski@gmail.com>
Link: https://lore.kernel.org/r/20220909023358.76881-1-marek.bykowski@gmail.com
Signed-off-by: Rob Herring <robh@kernel.org>
2022-09-09 08:11:46 -05:00
..
unittest-data of: overlay: unittest: add tests for overlay notifiers 2022-05-03 11:53:15 -05:00
address.c of: also handle dma-noncoherent in of_dma_is_coherent() 2022-07-28 15:30:20 -07:00
base.c of: move from strlcpy with unused retval to strscpy 2022-08-22 15:01:26 -05:00
device.c of: device: Fix missing of_node_put() in of_dma_set_restricted_buffer 2022-07-12 10:58:33 -06:00
dynamic.c of: Add missing 'Return' section in kerneldoc comments 2021-03-27 12:59:03 -06:00
fdt_address.c of: Use SPDX license tag for DT files 2018-01-08 08:22:45 -06:00
fdt.c of/fdt: Don't calculate initrd size from DT if start > end 2022-09-09 08:11:46 -05:00
irq.c of: irq: Report individual failures in of_irq_init() 2022-09-07 10:54:55 -05:00
Kconfig of: net: move of_net under net/ 2021-10-07 13:39:51 +01:00
kexec.c Devicetree updates for v6.0: 2022-08-04 18:08:34 -07:00
kobj.c of: kobj: make of_node_is_(initialized|attached) parameters const 2021-10-20 13:37:25 -05:00
Makefile of: net: move of_net under net/ 2021-10-07 13:39:51 +01:00
of_numa.c of, numa: Fetch empty NUMA node ID from distance map 2021-10-04 13:13:44 -05:00
of_private.h of: kobj: make of_node_is_(initialized|attached) parameters const 2021-10-20 13:37:25 -05:00
of_reserved_mem.c of: reserved-memory: Print allocation/reservation failures as error 2022-06-28 14:15:36 -06:00
overlay.c of: overlay: Simplify of_overlay_fdt_apply() tail 2022-07-19 15:56:48 -06:00
pdt.c of: Remove struct device_node.type pointer 2019-01-10 16:24:44 -06:00
platform.c drm for 5.19-rc1 2022-05-25 16:18:27 -07:00
property.c Devicetree updates for v5.19: 2022-05-25 14:56:06 -07:00
resolver.c of: overlay: log the error cause on resolver failure 2020-03-02 11:32:44 -06:00
unittest.c of: unittest: taint the kernel when of unittest runs 2022-08-25 13:59:08 -05:00