From: Dan Williams dan.j.williams@intel.com
[ Upstream commit 6041186a32585fc7a1d0f6cfe2f138b05fdc3c82 ]
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@dwi... Signed-off-by: Dan Williams dan.j.williams@intel.com Reported-by: Guenter Roeck groeck@google.com Reviewed-by: Kees Cook keescook@chromium.org Cc: Mathieu Desnoyers mathieu.desnoyers@efficios.com Cc: Thomas Gleixner tglx@linutronix.de Cc: Mike Rapoport rppt@linux.ibm.com Cc: Russell King rmk@armlinux.org.uk Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- init/main.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/init/main.c b/init/main.c index e083fac08aed..020972fed117 100644 --- a/init/main.c +++ b/init/main.c @@ -568,6 +568,8 @@ asmlinkage __visible void __init start_kernel(void) 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, @@ -577,8 +579,6 @@ asmlinkage __visible void __init start_kernel(void) 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()