8 files changed, 46 insertions, 24 deletions

diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index 061ac17ee974..f438a44bf8f9 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -1148,7 +1148,6 @@ ENTRY(ftrace_regs_caller)
          * ip location, and move flags into the return ip location.
          */
         pushl 4(%esp)   /* save return ip into ip slot */
-        subl $MCOUNT_INSN_SIZE, (%esp)  /* Adjust ip */
 
         pushl $0        /* Load 0 into orig_ax */
         pushl %gs
@@ -1169,6 +1168,7 @@ ENTRY(ftrace_regs_caller)
         movl $__KERNEL_CS,13*4(%esp)
 
         movl 12*4(%esp), %eax   /* Load ip (1st parameter) */
+        subl $MCOUNT_INSN_SIZE, %eax    /* Adjust ip */
         movl 0x4(%ebp), %edx    /* Load parent ip (2nd parameter) */
         leal function_trace_op, %ecx /* Save ftrace_pos in 3rd parameter */
         pushl %esp              /* Save pt_regs as 4th parameter */
@@ -1180,7 +1180,6 @@ GLOBAL(ftrace_regs_call)
         movl 14*4(%esp), %eax   /* Move flags back into cs */
         movl %eax, 13*4(%esp)   /* Needed to keep addl from modifying flags */
         movl 12*4(%esp), %eax   /* Get return ip from regs->ip */
-        addl $MCOUNT_INSN_SIZE, %eax
         movl %eax, 14*4(%esp)   /* Put return ip back for ret */
 
         popl %ebx
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index ed767b747fe5..e9cc2b32bdf4 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -165,6 +165,10 @@ GLOBAL(ftrace_regs_call)
         movq EFLAGS(%rsp), %rax
         movq %rax, SS(%rsp)
 
+        /* Handlers can change the RIP */
+        movq RIP(%rsp), %rax
+        movq %rax, SS+8(%rsp)
+
         /* restore the rest of pt_regs */
         movq R15(%rsp), %r15
         movq R14(%rsp), %r14
diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c
index 47ae1023a93c..b7c2a85d1926 100644
--- a/arch/x86/kernel/kprobes.c
+++ b/arch/x86/kernel/kprobes.c
@@ -541,6 +541,8 @@ reenter_kprobe(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb
         return 1;
 }
 
+static void __kprobes skip_singlestep(struct kprobe *p, struct pt_regs *regs,
+                                      struct kprobe_ctlblk *kcb);
 /*
  * Interrupts are disabled on entry as trap3 is an interrupt gate and they
  * remain disabled throughout this function.
@@ -599,6 +601,12 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
         } else if (kprobe_running()) {
                 p = __this_cpu_read(current_kprobe);
                 if (p->break_handler && p->break_handler(p, regs)) {
+#ifdef KPROBES_CAN_USE_FTRACE
+                        if (kprobe_ftrace(p)) {
+                                skip_singlestep(p, regs, kcb);
+                                return 1;
+                        }
+#endif
                         setup_singlestep(p, regs, kcb, 0);
                         return 1;
                 }
@@ -1053,6 +1061,21 @@ int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
 }
 
 #ifdef KPROBES_CAN_USE_FTRACE
+static void __kprobes skip_singlestep(struct kprobe *p, struct pt_regs *regs,
+                                      struct kprobe_ctlblk *kcb)
+{
+        /*
+         * Emulate singlestep (and also recover regs->ip)
+         * as if there is a 5byte nop
+         */
+        regs->ip = (unsigned long)p->addr + MCOUNT_INSN_SIZE;
+        if (unlikely(p->post_handler)) {
+                kcb->kprobe_status = KPROBE_HIT_SSDONE;
+                p->post_handler(p, regs, 0);
+        }
+        __this_cpu_write(current_kprobe, NULL);
+}
+
 /* Ftrace callback handler for kprobes */
 void __kprobes kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
                                      struct ftrace_ops *ops, struct pt_regs *regs)
@@ -1072,21 +1095,17 @@ void __kprobes kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
         if (kprobe_running()) {
                 kprobes_inc_nmissed_count(p);
         } else {
-                regs->ip += sizeof(kprobe_opcode_t);
+                /* Kprobe handler expects regs->ip = ip + 1 as breakpoint hit */
+                regs->ip = ip + sizeof(kprobe_opcode_t);
 
                 __this_cpu_write(current_kprobe, p);
                 kcb->kprobe_status = KPROBE_HIT_ACTIVE;
-                if (p->pre_handler)
-                        p->pre_handler(p, regs);
-
-                if (unlikely(p->post_handler)) {
-                        /* Emulate singlestep as if there is a 5byte nop */
-                        regs->ip = ip + MCOUNT_INSN_SIZE;
-                        kcb->kprobe_status = KPROBE_HIT_SSDONE;
-                        p->post_handler(p, regs, 0);
-                }
-                __this_cpu_write(current_kprobe, NULL);
-                regs->ip = ip;  /* Recover for next callback */
+                if (!p->pre_handler || !p->pre_handler(p, regs))
+                        skip_singlestep(p, regs, kcb);
+                /*
+                 * If pre_handler returns !0, it sets regs->ip and
+                 * resets current kprobe.
+                 */
         }
 end:
         local_irq_restore(flags);
diff --git a/kernel/Makefile b/kernel/Makefile
index c0cc67ad764c..29d993be7dba 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -98,7 +98,7 @@ obj-$(CONFIG_COMPAT_BINFMT_ELF) += elfcore.o
 obj-$(CONFIG_BINFMT_ELF_FDPIC) += elfcore.o
 obj-$(CONFIG_FUNCTION_TRACER) += trace/
 obj-$(CONFIG_TRACING) += trace/
-obj-$(CONFIG_X86_DS) += trace/
+obj-$(CONFIG_TRACE_CLOCK) += trace/
 obj-$(CONFIG_RING_BUFFER) += trace/
 obj-$(CONFIG_TRACEPOINTS) += trace/
 obj-$(CONFIG_IRQ_WORK) += irq_work.o
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 35b4315d84f5..098f396aa409 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1418,9 +1418,6 @@ static __kprobes int check_kprobe_address_safe(struct kprobe *p,
                 /* Given address is not on the instruction boundary */
                 if ((unsigned long)p->addr != ftrace_addr)
                         return -EILSEQ;
-                /* break_handler (jprobe) can not work with ftrace */
-                if (p->break_handler)
-                        return -EINVAL;
                 p->flags |= KPROBE_FLAG_FTRACE;
 #else   /* !KPROBES_CAN_USE_FTRACE */
                 return -EINVAL;
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 9301a0e35e0c..4cea4f41c1d9 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -62,8 +62,12 @@ config HAVE_C_RECORDMCOUNT
 config TRACER_MAX_TRACE
         bool
 
+config TRACE_CLOCK
+        bool
+
 config RING_BUFFER
         bool
+        select TRACE_CLOCK
 
 config FTRACE_NMI_ENTER
        bool
@@ -114,6 +118,7 @@ config TRACING
         select NOP_TRACER
         select BINARY_PRINTF
         select EVENT_TRACING
+        select TRACE_CLOCK
 
 config GENERIC_TRACER
         bool
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index 837090808aac..d7e2068e4b71 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -19,11 +19,7 @@ endif
 
 CFLAGS_trace_events_filter.o := -I$(src)
 
-#
-# Make the trace clocks available generally: it's infrastructure
-# relied on by ptrace for example:
-#
-obj-y += trace_clock.o
+obj-$(CONFIG_TRACE_CLOCK) += trace_clock.o
 
 obj-$(CONFIG_FUNCTION_TRACER) += libftrace.o
 obj-$(CONFIG_RING_BUFFER) += ring_buffer.o
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 6825d833a257..bbb0e63d78e9 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1646,9 +1646,11 @@ static __init void event_trace_self_tests(void)
                 event_test_stuff();
 
                 ret = __ftrace_set_clr_event(NULL, system->name, NULL, 0);
-                if (WARN_ON_ONCE(ret))
+                if (WARN_ON_ONCE(ret)) {
                         pr_warning("error disabling system %s\n",
                                    system->name);
+                        continue;
+                }
 
                 pr_cont("OK\n");
         }