From d7880812b3594d3c6dcbe3cfd71dabb17347d082 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 10 Jun 2013 16:52:03 +0200 Subject: idle: Add the stack canary init to cpu_startup_entry() Moving x86 to the generic idle implementation (commit 7d1a9417 "x86: Use generic idle loop") wreckaged the stack protector. I stupidly missed that boot_init_stack_canary() must be inlined from a function which never returns, but I put that call into arch_cpu_idle_prepare() which of course returns. I pondered to play tricks with arch_cpu_idle_prepare() first, but then I noticed, that the other archs which have implemented the stackprotector (ARM and SH) do not initialize the canary for the non-boot cpus. So I decided to move the boot_init_stack_canary() call into cpu_startup_entry() ifdeffed with an CONFIG_X86 for now. This #ifdef is just a temporary measure as I don't want to inflict the boot_init_stack_canary() call on ARM and SH that late in the cycle. I'll queue a patch for 3.11 which removes the #ifdef if the ARM/SH maintainers have no objection. Reported-by: Wouter van Kesteren Cc: x86@kernel.org Cc: Russell King Cc: Paul Mundt Signed-off-by: Thomas Gleixner diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 4e7a37f..81a5f5e 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -277,18 +277,6 @@ void exit_idle(void) } #endif -void arch_cpu_idle_prepare(void) -{ - /* - * If we're the non-boot CPU, nothing set the stack canary up - * for us. CPU0 already has it initialized but no harm in - * doing it again. This is a good place for updating it, as - * we wont ever return from this function (so the invalid - * canaries already on the stack wont ever trigger). - */ - boot_init_stack_canary(); -} - void arch_cpu_idle_enter(void) { local_touch_nmi(); diff --git a/kernel/cpu/idle.c b/kernel/cpu/idle.c index d5585f5..bf2ee1a 100644 --- a/kernel/cpu/idle.c +++ b/kernel/cpu/idle.c @@ -5,6 +5,7 @@ #include #include #include +#include #include @@ -112,6 +113,21 @@ static void cpu_idle_loop(void) void cpu_startup_entry(enum cpuhp_state state) { + /* + * This #ifdef needs to die, but it's too late in the cycle to + * make this generic (arm and sh have never invoked the canary + * init for the non boot cpus!). Will be fixed in 3.11 + */ +#ifdef CONFIG_X86 + /* + * If we're the non-boot CPU, nothing set the stack canary up + * for us. The boot CPU already has it initialized but no harm + * in doing it again. This is a good place for updating it, as + * we wont ever return from this function (so the invalid + * canaries already on the stack wont ever trigger). + */ + boot_init_stack_canary(); +#endif current_set_polling(); arch_cpu_idle_prepare(); cpu_idle_loop(); -- cgit v0.10.2