diff options
Diffstat (limited to 'arch/x86/kernel/ftrace.c')
| -rw-r--r-- | arch/x86/kernel/ftrace.c | 24 |
1 files changed, 21 insertions, 3 deletions
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index 8639bb2ae058..0651e974dcb3 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -24,7 +24,7 @@ #include <trace/syscall.h> -#include <asm/cacheflush.h> +#include <asm/set_memory.h> #include <asm/kprobes.h> #include <asm/ftrace.h> #include <asm/nops.h> @@ -533,9 +533,15 @@ static void do_sync_core(void *data) static void run_sync(void) { - int enable_irqs = irqs_disabled(); + int enable_irqs; - /* We may be called with interrupts disbled (on bootup). */ + /* No need to sync if there's only one CPU */ + if (num_online_cpus() == 1) + return; + + enable_irqs = irqs_disabled(); + + /* We may be called with interrupts disabled (on bootup). */ if (enable_irqs) local_irq_enable(); on_each_cpu(do_sync_core, NULL, 1); @@ -983,6 +989,18 @@ void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent, unsigned long return_hooker = (unsigned long) &return_to_handler; + /* + * When resuming from suspend-to-ram, this function can be indirectly + * called from early CPU startup code while the CPU is in real mode, + * which would fail miserably. Make sure the stack pointer is a + * virtual address. + * + * This check isn't as accurate as virt_addr_valid(), but it should be + * good enough for this purpose, and it's fast. + */ + if (unlikely((long)__builtin_frame_address(0) >= 0)) + return; + if (unlikely(ftrace_graph_is_dead())) return; |