4.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tobias Klauser <tklauser@xxxxxxxxxx> commit 921d701e6f31e1ffaca3560416af1aa04edb4c4f upstream. Make sure to reserve the boot memory for the flattened device tree. Otherwise it might get overwritten, e.g. when initial_boot_params is copied, leading to a corrupted FDT and a boot hang/crash: bootconsole [early0] enabled Early console on uart16650 initialized at 0xf8001600 OF: fdt: Error -11 processing FDT Kernel panic - not syncing: setup_cpuinfo: No CPU found in devicetree! ---[ end Kernel panic - not syncing: setup_cpuinfo: No CPU found in devicetree! Guenter Roeck says: > I think I found the problem. In unflatten_and_copy_device_tree(), with added > debug information: > > OF: fdt: initial_boot_params=c861e400, dt=c861f000 size=28874 (0x70ca) > > ... and then initial_boot_params is copied to dt, which results in corrupted > fdt since the memory overlaps. Looks like the initial_boot_params memory > is not reserved and (re-)allocated by early_init_dt_alloc_memory_arch(). Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx> Reference: http://lkml.kernel.org/r/20170226210338.GA19476@xxxxxxxxxxxx Tested-by: Guenter Roeck <linux@xxxxxxxxxxxx> Signed-off-by: Tobias Klauser <tklauser@xxxxxxxxxx> Acked-by: Ley Foon Tan <ley.foon.tan@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/nios2/kernel/prom.c | 7 +++++++ arch/nios2/kernel/setup.c | 3 +++ 2 files changed, 10 insertions(+) --- a/arch/nios2/kernel/prom.c +++ b/arch/nios2/kernel/prom.c @@ -48,6 +48,13 @@ void * __init early_init_dt_alloc_memory return alloc_bootmem_align(size, align); } +int __init early_init_dt_reserve_memory_arch(phys_addr_t base, phys_addr_t size, + bool nomap) +{ + reserve_bootmem(base, size, BOOTMEM_DEFAULT); + return 0; +} + void __init early_init_devtree(void *params) { __be32 *dtb = (u32 *)__dtb_start; --- a/arch/nios2/kernel/setup.c +++ b/arch/nios2/kernel/setup.c @@ -200,6 +200,9 @@ void __init setup_arch(char **cmdline_p) } #endif /* CONFIG_BLK_DEV_INITRD */ + early_init_fdt_reserve_self(); + early_init_fdt_scan_reserved_mem(); + unflatten_and_copy_device_tree(); setup_cpuinfo();