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Diffstat (limited to 'arch/x86/kernel/ftrace.c')
-rw-r--r--arch/x86/kernel/ftrace.c17
1 files changed, 10 insertions, 7 deletions
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 0927bb158ffc..4b73f5937f41 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;
}