diff options
Diffstat (limited to 'arch/x86/kernel/ftrace.c')
| -rw-r--r-- | arch/x86/kernel/ftrace.c | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index ba37bcb7f92b..024c3053dbba 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -22,6 +22,7 @@ #include <linux/init.h> #include <linux/list.h> #include <linux/module.h> +#include <linux/memory.h> #include <trace/syscall.h> @@ -34,16 +35,25 @@ #ifdef CONFIG_DYNAMIC_FTRACE int ftrace_arch_code_modify_prepare(void) + __acquires(&text_mutex) { + /* + * Need to grab text_mutex to prevent a race from module loading + * and live kernel patching from changing the text permissions while + * ftrace has it set to "read/write". + */ + mutex_lock(&text_mutex); set_kernel_text_rw(); set_all_modules_text_rw(); return 0; } int ftrace_arch_code_modify_post_process(void) + __releases(&text_mutex) { set_all_modules_text_ro(); set_kernel_text_ro(); + mutex_unlock(&text_mutex); return 0; } @@ -300,7 +310,6 @@ int ftrace_int3_handler(struct pt_regs *regs) ip = regs->ip - INT3_INSN_SIZE; -#ifdef CONFIG_X86_64 if (ftrace_location(ip)) { int3_emulate_call(regs, (unsigned long)ftrace_regs_caller); return 1; @@ -312,12 +321,6 @@ int ftrace_int3_handler(struct pt_regs *regs) int3_emulate_call(regs, ftrace_update_func_call); return 1; } -#else - if (ftrace_location(ip) || is_ftrace_caller(ip)) { - int3_emulate_jmp(regs, ip + CALL_INSN_SIZE); - return 1; - } -#endif return 0; } |