On Wed, 25 Oct 2017, Prarit Bhargava wrote:
> diff --git a/arch/x86/include/asm/processor.h
> b/arch/x86/include/asm/processor.h
> index b390ff76e58f..f4ab1edf4e24 100644
> --- a/arch/x86/include/asm/processor.h
> +++ b/arch/x86/include/asm/processor.h
> @@ -124,8 +124,10 @@ struct cpuinfo_x86 {
> u16 booted_cores;
> /* Physical processor id: */
> u16 phys_proc_id;
> - /* Logical processor id: */
> + /* Logical processor (package) id: */
> u16 logical_proc_id;
> + /* Physical package ID */
> + u16 phys_pkg_id;
How is this new field used aside of being written to and how is it
different from phys_proc_id? AFAICT, it's the same as all callers to
topology_update_package_map() are handing in cpu_data->phys_proc_id.
> +/**
> + * topology_phys_to_logical_pkg - Map a physical package id to a logical
> + *
> + * Returns logical package id or -1 if not found
> + */
> +int topology_phys_to_logical_pkg(unsigned int phys_pkg)
> +{
> + int log_pkg;
> +
> + for (log_pkg = 0; log_pkg < logical_packages; log_pkg++)
> + if (logical_to_physical_pkg_map[log_pkg] == phys_pkg)
> + return log_pkg;
> +
> + return -1;
> +}
> +EXPORT_SYMBOL(topology_phys_to_logical_pkg);
....
> +
> + /* Allocate and copy a new array */
> + ltp_pkg_map_new = kmalloc(logical_packages * sizeof(u16), GFP_KERNEL);
> + BUG_ON(!ltp_pkg_map_new);
> + if (logical_to_physical_pkg_map) {
> + memcpy(ltp_pkg_map_new, logical_to_physical_pkg_map,
> + logical_packages * sizeof(u16));
> + kfree(logical_to_physical_pkg_map);
> }
> - physical_to_logical_pkg[pkg] = new;
> + logical_to_physical_pkg_map = ltp_pkg_map_new;
This lacks serialization and is therefore broken against a concurrent
topology_phys_to_logical_pkg() call for obvious reasons. The current user
is probably safe, but this really needs to be fixed now.
Thanks,
tglx
