From: Dan Williams <dan.j.williams@xxxxxxxxx> Subject: init: initialize jump labels before command line option parsing When a module option, or core kernel argument, toggles a static-key it requires jump labels to be initialized early. While x86, PowerPC, and ARM64 arrange for jump_label_init() to be called before parse_args(), ARM does not. Kernel command line: rdinit=/sbin/init page_alloc.shuffle=1 panic=-1 console=ttyAMA0,115200 page_alloc.shuffle=1 ------------[ cut here ]------------ WARNING: CPU: 0 PID: 0 at ./include/linux/jump_label.h:303 page_alloc_shuffle+0x12c/0x1ac static_key_enable(): static key 'page_alloc_shuffle_key+0x0/0x4' used before call to jump_label_init() Modules linked in: CPU: 0 PID: 0 Comm: swapper Not tainted 5.1.0-rc4-next-20190410-00003-g3367c36ce744 #1 Hardware name: ARM Integrator/CP (Device Tree) [<c0011c68>] (unwind_backtrace) from [<c000ec48>] (show_stack+0x10/0x18) [<c000ec48>] (show_stack) from [<c07e9710>] (dump_stack+0x18/0x24) [<c07e9710>] (dump_stack) from [<c001bb1c>] (__warn+0xe0/0x108) [<c001bb1c>] (__warn) from [<c001bb88>] (warn_slowpath_fmt+0x44/0x6c) [<c001bb88>] (warn_slowpath_fmt) from [<c0b0c4a8>] (page_alloc_shuffle+0x12c/0x1ac) [<c0b0c4a8>] (page_alloc_shuffle) from [<c0b0c550>] (shuffle_store+0x28/0x48) [<c0b0c550>] (shuffle_store) from [<c003e6a0>] (parse_args+0x1f4/0x350) [<c003e6a0>] (parse_args) from [<c0ac3c00>] (start_kernel+0x1c0/0x488) Move the fallback call to jump_label_init() to occur before parse_args(). The redundant calls to jump_label_init() in other archs are left intact in case they have static key toggling use cases that are even earlier than option parsing. Link: http://lkml.kernel.org/r/155544804466.1032396.13418949511615676665.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx> Reported-by: Guenter Roeck <groeck@xxxxxxxxxx> Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx> Cc: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx> Cc: Russell King <rmk@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- init/main.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/init/main.c~init-initialize-jump-labels-before-command-line-option-parsing +++ a/init/main.c @@ -582,6 +582,8 @@ asmlinkage __visible void __init start_k page_alloc_init(); pr_notice("Kernel command line: %s\n", boot_command_line); + /* parameters may set static keys */ + jump_label_init(); parse_early_param(); after_dashes = parse_args("Booting kernel", static_command_line, __start___param, @@ -591,8 +593,6 @@ asmlinkage __visible void __init start_k parse_args("Setting init args", after_dashes, NULL, 0, -1, -1, NULL, set_init_arg); - jump_label_init(); - /* * These use large bootmem allocations and must precede * kmem_cache_init() _
