Merge tag 'trace-v5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:
 "The major changes in this tracing update includes:

   - Removal of non-DYNAMIC_FTRACE from 32bit x86

   - Removal of mcount support from x86

   - Emulating a call from int3 on x86_64, fixes live kernel patching

   - Consolidated Tracing Error logs file

  Minor updates:

   - Removal of klp_check_compiler_support()

   - kdb ftrace dumping output changes

   - Accessing and creating ftrace instances from inside the kernel

   - Clean up of #define if macro

   - Introduction of TRACE_EVENT_NOP() to disable trace events based on
     config options

  And other minor fixes and clean ups"

* tag 'trace-v5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (44 commits)
  x86: Hide the int3_emulate_call/jmp functions from UML
  livepatch: Remove klp_check_compiler_support()
  ftrace/x86: Remove mcount support
  ftrace/x86_32: Remove support for non DYNAMIC_FTRACE
  tracing: Simplify "if" macro code
  tracing: Fix documentation about disabling options using trace_options
  tracing: Replace kzalloc with kcalloc
  tracing: Fix partial reading of trace event's id file
  tracing: Allow RCU to run between postponed startup tests
  tracing: Fix white space issues in parse_pred() function
  tracing: Eliminate const char[] auto variables
  ring-buffer: Fix mispelling of Calculate
  tracing: probeevent: Fix to make the type of $comm string
  tracing: probeevent: Do not accumulate on ret variable
  tracing: uprobes: Re-enable $comm support for uprobe events
  ftrace/x86_64: Emulate call function while updating in breakpoint handler
  x86_64: Allow breakpoints to emulate call instructions
  x86_64: Add gap to int3 to allow for call emulation
  tracing: kdb: Allow ftdump to skip all but the last few entries
  tracing: Add trace_total_entries() / trace_total_entries_cpu()
  ...

Documentation/trace/ftrace.rst

@@ -765,6 +765,37 @@ Here is the list of current tracers that may be configured.
 	tracers from tracing simply echo "nop" into
 	current_tracer.
 
+Error conditions
+----------------
+
+  For most ftrace commands, failure modes are obvious and communicated
+  using standard return codes.
+
+  For other more involved commands, extended error information may be
+  available via the tracing/error_log file.  For the commands that
+  support it, reading the tracing/error_log file after an error will
+  display more detailed information about what went wrong, if
+  information is available.  The tracing/error_log file is a circular
+  error log displaying a small number (currently, 8) of ftrace errors
+  for the last (8) failed commands.
+
+  The extended error information and usage takes the form shown in
+  this example::
+
+    # echo xxx > /sys/kernel/debug/tracing/events/sched/sched_wakeup/trigger
+    echo: write error: Invalid argument
+
+    # cat /sys/kernel/debug/tracing/error_log
+    [ 5348.887237] location: error: Couldn't yyy: zzz
+      Command: xxx
+               ^
+    [ 7517.023364] location: error: Bad rrr: sss
+      Command: ppp qqq
+                   ^
+
+  To clear the error log, echo the empty string into it::
+
+    # echo > /sys/kernel/debug/tracing/error_log
 
 Examples of using the tracer
 ----------------------------

Documentation/trace/histogram.rst

@@ -199,20 +199,8 @@ Extended error information
 
   For some error conditions encountered when invoking a hist trigger
   command, extended error information is available via the
-  corresponding event's 'hist' file.  Reading the hist file after an
-  error will display more detailed information about what went wrong,
-  if information is available.  This extended error information will
-  be available until the next hist trigger command for that event.
-
-  If available for a given error condition, the extended error
-  information and usage takes the following form::
-
-    # echo xxx > /sys/kernel/debug/tracing/events/sched/sched_wakeup/trigger
-    echo: write error: Invalid argument
-
-    # cat /sys/kernel/debug/tracing/events/sched/sched_wakeup/hist
-    ERROR: Couldn't yyy: zzz
-      Last command: xxx
+  tracing/error_log file.  See Error Conditions in
+  :file:`Documentation/trace/ftrace.rst` for details.
 
 6.2 'hist' trigger examples
 ---------------------------

arch/nds32/kernel/ftrace.c

@@ -7,7 +7,6 @@
 #ifndef CONFIG_DYNAMIC_FTRACE
 extern void (*ftrace_trace_function)(unsigned long, unsigned long,
 				     struct ftrace_ops*, struct pt_regs*);
-extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace);
 extern void ftrace_graph_caller(void);
 
 noinline void __naked ftrace_stub(unsigned long ip, unsigned long parent_ip,

arch/parisc/kernel/ftrace.c

@@ -51,7 +51,6 @@ void notrace __hot ftrace_function_trampoline(unsigned long parent,
 				unsigned long org_sp_gr3)
 {
 	extern ftrace_func_t ftrace_trace_function;  /* depends on CONFIG_DYNAMIC_FTRACE */
-	extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace);
 
 	if (ftrace_trace_function != ftrace_stub) {
 		/* struct ftrace_ops *op, struct pt_regs *regs); */

arch/powerpc/include/asm/livepatch.h

@@ -24,11 +24,6 @@
 #include <linux/sched/task_stack.h>
 
 #ifdef CONFIG_LIVEPATCH
-static inline int klp_check_compiler_support(void)
-{
-	return 0;
-}
-
 static inline void klp_arch_set_pc(struct pt_regs *regs, unsigned long ip)
 {
 	regs->nip = ip;

arch/s390/include/asm/livepatch.h

@@ -13,11 +13,6 @@
 
 #include <asm/ptrace.h>
 
-static inline int klp_check_compiler_support(void)
-{
-	return 0;
-}
-
 static inline void klp_arch_set_pc(struct pt_regs *regs, unsigned long ip)
 {
 	regs->psw.addr = ip;

arch/x86/Kconfig

@@ -31,6 +31,17 @@ config X86_64
 	select SWIOTLB
 	select ARCH_HAS_SYSCALL_WRAPPER
 
+config FORCE_DYNAMIC_FTRACE
+	def_bool y
+	depends on X86_32
+	depends on FUNCTION_TRACER
+	select DYNAMIC_FTRACE
+	help
+	 We keep the static function tracing (!DYNAMIC_FTRACE) around
+	 in order to test the non static function tracing in the
+	 generic code, as other architectures still use it. But we
+	 only need to keep it around for x86_64. No need to keep it
+	 for x86_32. For x86_32, force DYNAMIC_FTRACE. 
 #
 # Arch settings
 #

arch/x86/entry/entry_64.S

@@ -878,7 +878,7 @@ apicinterrupt IRQ_WORK_VECTOR			irq_work_interrupt		smp_irq_work_interrupt
  * @paranoid == 2 is special: the stub will never switch stacks.  This is for
  * #DF: if the thread stack is somehow unusable, we'll still get a useful OOPS.
  */
-.macro idtentry sym do_sym has_error_code:req paranoid=0 shift_ist=-1 ist_offset=0
+.macro idtentry sym do_sym has_error_code:req paranoid=0 shift_ist=-1 ist_offset=0 create_gap=0
 ENTRY(\sym)
 	UNWIND_HINT_IRET_REGS offset=\has_error_code*8
 
@@ -898,6 +898,20 @@ ENTRY(\sym)
 	jnz	.Lfrom_usermode_switch_stack_\@
 	.endif
 
+	.if \create_gap == 1
+	/*
+	 * If coming from kernel space, create a 6-word gap to allow the
+	 * int3 handler to emulate a call instruction.
+	 */
+	testb	$3, CS-ORIG_RAX(%rsp)
+	jnz	.Lfrom_usermode_no_gap_\@
+	.rept	6
+	pushq	5*8(%rsp)
+	.endr
+	UNWIND_HINT_IRET_REGS offset=8
+.Lfrom_usermode_no_gap_\@:
+	.endif
+
 	.if \paranoid
 	call	paranoid_entry
 	.else
@@ -1129,7 +1143,7 @@ apicinterrupt3 HYPERV_STIMER0_VECTOR \
 #endif /* CONFIG_HYPERV */
 
 idtentry debug			do_debug		has_error_code=0	paranoid=1 shift_ist=IST_INDEX_DB ist_offset=DB_STACK_OFFSET
-idtentry int3			do_int3			has_error_code=0
+idtentry int3			do_int3			has_error_code=0	create_gap=1
 idtentry stack_segment		do_stack_segment	has_error_code=1
 
 #ifdef CONFIG_XEN_PV

arch/x86/include/asm/ftrace.h

@@ -3,12 +3,10 @@
 #define _ASM_X86_FTRACE_H
 
 #ifdef CONFIG_FUNCTION_TRACER
-#ifdef CC_USING_FENTRY
-# define MCOUNT_ADDR		((unsigned long)(__fentry__))
-#else
-# define MCOUNT_ADDR		((unsigned long)(mcount))
-# define HAVE_FUNCTION_GRAPH_FP_TEST
+#ifndef CC_USING_FENTRY
+# error Compiler does not support fentry?
 #endif
+# define MCOUNT_ADDR		((unsigned long)(__fentry__))
 #define MCOUNT_INSN_SIZE	5 /* sizeof mcount call */
 
 #ifdef CONFIG_DYNAMIC_FTRACE

arch/x86/include/asm/livepatch.h

@@ -24,14 +24,6 @@
 #include <asm/setup.h>
 #include <linux/ftrace.h>
 
-static inline int klp_check_compiler_support(void)
-{
-#ifndef CC_USING_FENTRY
-	return 1;
-#endif
-	return 0;
-}
-
 static inline void klp_arch_set_pc(struct pt_regs *regs, unsigned long ip)
 {
 	regs->ip = ip;

arch/x86/include/asm/text-patching.h

@@ -42,4 +42,34 @@ extern int after_bootmem;
 extern __ro_after_init struct mm_struct *poking_mm;
 extern __ro_after_init unsigned long poking_addr;
 
+#ifndef CONFIG_UML_X86
+static inline void int3_emulate_jmp(struct pt_regs *regs, unsigned long ip)
+{
+	regs->ip = ip;
+}
+
+#define INT3_INSN_SIZE 1
+#define CALL_INSN_SIZE 5
+
+#ifdef CONFIG_X86_64
+static inline void int3_emulate_push(struct pt_regs *regs, unsigned long val)
+{
+	/*
+	 * The int3 handler in entry_64.S adds a gap between the
+	 * stack where the break point happened, and the saving of
+	 * pt_regs. We can extend the original stack because of
+	 * this gap. See the idtentry macro's create_gap option.
+	 */
+	regs->sp -= sizeof(unsigned long);
+	*(unsigned long *)regs->sp = val;
+}
+
+static inline void int3_emulate_call(struct pt_regs *regs, unsigned long func)
+{
+	int3_emulate_push(regs, regs->ip - INT3_INSN_SIZE + CALL_INSN_SIZE);
+	int3_emulate_jmp(regs, func);
+}
+#endif /* CONFIG_X86_64 */
+#endif /* !CONFIG_UML_X86 */
+
 #endif /* _ASM_X86_TEXT_PATCHING_H */

arch/x86/kernel/ftrace.c

@@ -29,6 +29,7 @@
 #include <asm/kprobes.h>
 #include <asm/ftrace.h>
 #include <asm/nops.h>
+#include <asm/text-patching.h>
 
 #ifdef CONFIG_DYNAMIC_FTRACE
 
@@ -231,6 +232,7 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 }
 
 static unsigned long ftrace_update_func;
+static unsigned long ftrace_update_func_call;
 
 static int update_ftrace_func(unsigned long ip, void *new)
 {
@@ -259,6 +261,8 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
 	unsigned char *new;
 	int ret;
 
+	ftrace_update_func_call = (unsigned long)func;
+
 	new = ftrace_call_replace(ip, (unsigned long)func);
 	ret = update_ftrace_func(ip, new);
 
@@ -294,13 +298,28 @@ int ftrace_int3_handler(struct pt_regs *regs)
 	if (WARN_ON_ONCE(!regs))
 		return 0;
 
-	ip = regs->ip - 1;
-	if (!ftrace_location(ip) && !is_ftrace_caller(ip))
-		return 0;
-
-	regs->ip += MCOUNT_INSN_SIZE - 1;
+	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;
+	} else if (is_ftrace_caller(ip)) {
+		if (!ftrace_update_func_call) {
+			int3_emulate_jmp(regs, ip + CALL_INSN_SIZE);
+			return 1;
+		}
+		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;
 }
 NOKPROBE_SYMBOL(ftrace_int3_handler);
 
@@ -865,6 +884,8 @@ void arch_ftrace_update_trampoline(struct ftrace_ops *ops)
 
 	func = ftrace_ops_get_func(ops);
 
+	ftrace_update_func_call = (unsigned long)func;
+
 	/* Do a safe modify in case the trampoline is executing */
 	new = ftrace_call_replace(ip, (unsigned long)func);
 	ret = update_ftrace_func(ip, new);
@@ -966,6 +987,7 @@ static int ftrace_mod_jmp(unsigned long ip, void *func)
 {
 	unsigned char *new;
 
+	ftrace_update_func_call = 0UL;
 	new = ftrace_jmp_replace(ip, (unsigned long)func);
 
 	return update_ftrace_func(ip, new);

arch/x86/kernel/ftrace_32.S

@@ -10,22 +10,10 @@
 #include <asm/ftrace.h>
 #include <asm/nospec-branch.h>
 
-#ifdef CC_USING_FENTRY
 # define function_hook	__fentry__
 EXPORT_SYMBOL(__fentry__)
-#else
-# define function_hook	mcount
-EXPORT_SYMBOL(mcount)
-#endif
-
-#ifdef CONFIG_DYNAMIC_FTRACE
-
-/* mcount uses a frame pointer even if CONFIG_FRAME_POINTER is not set */
-#if !defined(CC_USING_FENTRY) || defined(CONFIG_FRAME_POINTER)
-# define USING_FRAME_POINTER
-#endif
 
-#ifdef USING_FRAME_POINTER
+#ifdef CONFIG_FRAME_POINTER
 # define MCOUNT_FRAME			1	/* using frame = true  */
 #else
 # define MCOUNT_FRAME			0	/* using frame = false */
@@ -37,8 +25,7 @@ END(function_hook)
 
 ENTRY(ftrace_caller)
 
-#ifdef USING_FRAME_POINTER
-# ifdef CC_USING_FENTRY
+#ifdef CONFIG_FRAME_POINTER
 	/*
 	 * Frame pointers are of ip followed by bp.
 	 * Since fentry is an immediate jump, we are left with
@@ -49,7 +36,7 @@ ENTRY(ftrace_caller)
 	pushl	%ebp
 	movl	%esp, %ebp
 	pushl	2*4(%esp)			/* function ip */
-# endif
+
 	/* For mcount, the function ip is directly above */
 	pushl	%ebp
 	movl	%esp, %ebp
@@ -59,7 +46,7 @@ ENTRY(ftrace_caller)
 	pushl	%edx
 	pushl	$0				/* Pass NULL as regs pointer */
 
-#ifdef USING_FRAME_POINTER
+#ifdef CONFIG_FRAME_POINTER
 	/* Load parent ebp into edx */
 	movl	4*4(%esp), %edx
 #else
@@ -82,13 +69,11 @@ ftrace_call:
 	popl	%edx
 	popl	%ecx
 	popl	%eax
-#ifdef USING_FRAME_POINTER
+#ifdef CONFIG_FRAME_POINTER
 	popl	%ebp
-# ifdef CC_USING_FENTRY
 	addl	$4,%esp				/* skip function ip */
 	popl	%ebp				/* this is the orig bp */
 	addl	$4, %esp			/* skip parent ip */
-# endif
 #endif
 .Lftrace_ret:
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
@@ -133,11 +118,7 @@ ENTRY(ftrace_regs_caller)
 
 	movl	12*4(%esp), %eax		/* Load ip (1st parameter) */
 	subl	$MCOUNT_INSN_SIZE, %eax		/* Adjust ip */
-#ifdef CC_USING_FENTRY
 	movl	15*4(%esp), %edx		/* Load parent ip (2nd parameter) */
-#else
-	movl	0x4(%ebp), %edx			/* Load parent ip (2nd parameter) */
-#endif
 	movl	function_trace_op, %ecx		/* Save ftrace_pos in 3rd parameter */
 	pushl	%esp				/* Save pt_regs as 4th parameter */
 
@@ -170,43 +151,6 @@ GLOBAL(ftrace_regs_call)
 	lea	3*4(%esp), %esp			/* Skip orig_ax, ip and cs */
 
 	jmp	.Lftrace_ret
-#else /* ! CONFIG_DYNAMIC_FTRACE */
-
-ENTRY(function_hook)
-	cmpl	$__PAGE_OFFSET, %esp
-	jb	ftrace_stub			/* Paging not enabled yet? */
-
-	cmpl	$ftrace_stub, ftrace_trace_function
-	jnz	.Ltrace
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-	cmpl	$ftrace_stub, ftrace_graph_return
-	jnz	ftrace_graph_caller
-
-	cmpl	$ftrace_graph_entry_stub, ftrace_graph_entry
-	jnz	ftrace_graph_caller
-#endif
-.globl ftrace_stub
-ftrace_stub:
-	ret
-
-	/* taken from glibc */
-.Ltrace:
-	pushl	%eax
-	pushl	%ecx
-	pushl	%edx
-	movl	0xc(%esp), %eax
-	movl	0x4(%ebp), %edx
-	subl	$MCOUNT_INSN_SIZE, %eax
-
-	movl	ftrace_trace_function, %ecx
-	CALL_NOSPEC %ecx
-
-	popl	%edx
-	popl	%ecx
-	popl	%eax
-	jmp	ftrace_stub
-END(function_hook)
-#endif /* CONFIG_DYNAMIC_FTRACE */
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 ENTRY(ftrace_graph_caller)
@@ -215,13 +159,8 @@ ENTRY(ftrace_graph_caller)
 	pushl	%edx
 	movl	3*4(%esp), %eax
 	/* Even with frame pointers, fentry doesn't have one here */
-#ifdef CC_USING_FENTRY
 	lea	4*4(%esp), %edx
 	movl	$0, %ecx
-#else
-	lea	0x4(%ebp), %edx
-	movl	(%ebp), %ecx
-#endif
 	subl	$MCOUNT_INSN_SIZE, %eax
 	call	prepare_ftrace_return
 	popl	%edx
@@ -234,11 +173,7 @@ END(ftrace_graph_caller)
 return_to_handler:
 	pushl	%eax
 	pushl	%edx
-#ifdef CC_USING_FENTRY
 	movl	$0, %eax
-#else
-	movl	%ebp, %eax
-#endif
 	call	ftrace_return_to_handler
 	movl	%eax, %ecx
 	popl	%edx

arch/x86/kernel/ftrace_64.S

@@ -13,22 +13,12 @@
 	.code64
 	.section .entry.text, "ax"
 
-#ifdef CC_USING_FENTRY
 # define function_hook	__fentry__
 EXPORT_SYMBOL(__fentry__)
-#else
-# define function_hook	mcount
-EXPORT_SYMBOL(mcount)
-#endif
 
 #ifdef CONFIG_FRAME_POINTER
-# ifdef CC_USING_FENTRY
 /* Save parent and function stack frames (rip and rbp) */
 #  define MCOUNT_FRAME_SIZE	(8+16*2)
-# else
-/* Save just function stack frame (rip and rbp) */
-#  define MCOUNT_FRAME_SIZE	(8+16)
-# endif
 #else
 /* No need to save a stack frame */
 # define MCOUNT_FRAME_SIZE	0
@@ -75,17 +65,13 @@ EXPORT_SYMBOL(mcount)
 	 * fentry is called before the stack frame is set up, where as mcount
 	 * is called afterward.
 	 */
-#ifdef CC_USING_FENTRY
+
 	/* Save the parent pointer (skip orig rbp and our return address) */
 	pushq \added+8*2(%rsp)
 	pushq %rbp
 	movq %rsp, %rbp
 	/* Save the return address (now skip orig rbp, rbp and parent) */
 	pushq \added+8*3(%rsp)
-#else
-	/* Can't assume that rip is before this (unless added was zero) */
-	pushq \added+8(%rsp)
-#endif
 	pushq %rbp
 	movq %rsp, %rbp
 #endif /* CONFIG_FRAME_POINTER */
@@ -113,12 +99,7 @@ EXPORT_SYMBOL(mcount)
 	movq %rdx, RBP(%rsp)
 
 	/* Copy the parent address into %rsi (second parameter) */
-#ifdef CC_USING_FENTRY
 	movq MCOUNT_REG_SIZE+8+\added(%rsp), %rsi
-#else
-	/* %rdx contains original %rbp */
-	movq 8(%rdx), %rsi
-#endif
 
 	 /* Move RIP to its proper location */
 	movq MCOUNT_REG_SIZE+\added(%rsp), %rdi
@@ -303,15 +284,8 @@ ENTRY(ftrace_graph_caller)
 	/* Saves rbp into %rdx and fills first parameter  */
 	save_mcount_regs
 
-#ifdef CC_USING_FENTRY
 	leaq MCOUNT_REG_SIZE+8(%rsp), %rsi
 	movq $0, %rdx	/* No framepointers needed */
-#else
-	/* Save address of the return address of traced function */
-	leaq 8(%rdx), %rsi
-	/* ftrace does sanity checks against frame pointers */
-	movq (%rdx), %rdx
-#endif
 	call	prepare_ftrace_return
 
 	restore_mcount_regs

include/linux/compiler.h

@@ -53,23 +53,24 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
  * "Define 'is'", Bill Clinton
  * "Define 'if'", Steven Rostedt
  */
-#define if(cond, ...) __trace_if( (cond , ## __VA_ARGS__) )
-#define __trace_if(cond) \
-	if (__builtin_constant_p(!!(cond)) ? !!(cond) :			\
-	({								\
-		int ______r;						\
+#define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
+
+#define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
+
+#define __trace_if_value(cond) ({			\
 	static struct ftrace_branch_data		\
 		__aligned(4)				\
 		__section("_ftrace_branch")		\
-			______f = {					\
+		__if_trace = {				\
 			.func = __func__,		\
 			.file = __FILE__,		\
 			.line = __LINE__,		\
 		};					\
-		______r = !!(cond);					\
-		______r ? ______f.miss_hit[1]++ : ______f.miss_hit[0]++;\
-		______r;						\
-	}))
+	(cond) ?					\
+		(__if_trace.miss_hit[1]++,1) :		\
+		(__if_trace.miss_hit[0]++,0);		\
+})
+
 #endif /* CONFIG_PROFILE_ALL_BRANCHES */
 
 #else

include/linux/ftrace.h

@@ -741,6 +741,8 @@ struct ftrace_graph_ret {
 typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
 typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
 
+extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace);
+
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 
 struct fgraph_ops {

include/linux/tracepoint.h

@@ -548,4 +548,19 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
 
 #define TRACE_EVENT_PERF_PERM(event, expr...)
 
+#define DECLARE_EVENT_NOP(name, proto, args)				\
+	static inline void trace_##name(proto)				\
+	{ }								\
+	static inline bool trace_##name##_enabled(void)			\
+	{								\
+		return false;						\
+	}
+
+#define TRACE_EVENT_NOP(name, proto, args, struct, assign, print)	\
+	DECLARE_EVENT_NOP(name, PARAMS(proto), PARAMS(args))
+
+#define DECLARE_EVENT_CLASS_NOP(name, proto, args, tstruct, assign, print)
+#define DEFINE_EVENT_NOP(template, name, proto, args)			\
+	DECLARE_EVENT_NOP(name, PARAMS(proto), PARAMS(args))
+
 #endif /* ifdef TRACE_EVENT (see note above) */

include/trace/define_trace.h

@@ -46,6 +46,12 @@
 		assign, print, reg, unreg)			\
 	DEFINE_TRACE_FN(name, reg, unreg)
 
+#undef TRACE_EVENT_NOP
+#define TRACE_EVENT_NOP(name, proto, args, struct, assign, print)
+
+#undef DEFINE_EVENT_NOP
+#define DEFINE_EVENT_NOP(template, name, proto, args)
+
 #undef DEFINE_EVENT
 #define DEFINE_EVENT(template, name, proto, args) \
 	DEFINE_TRACE(name)
@@ -102,6 +108,8 @@
 #undef TRACE_EVENT_FN
 #undef TRACE_EVENT_FN_COND
 #undef TRACE_EVENT_CONDITION
+#undef TRACE_EVENT_NOP
+#undef DEFINE_EVENT_NOP
 #undef DECLARE_EVENT_CLASS
 #undef DEFINE_EVENT
 #undef DEFINE_EVENT_FN

include/trace/events/rcu.h

@@ -7,6 +7,12 @@
 
 #include <linux/tracepoint.h>
 
+#ifdef CONFIG_RCU_TRACE
+#define TRACE_EVENT_RCU TRACE_EVENT
+#else
+#define TRACE_EVENT_RCU TRACE_EVENT_NOP
+#endif
+
 /*
  * Tracepoint for start/end markers used for utilization calculations.
  * By convention, the string is of the following forms:
@@ -35,8 +41,6 @@ TRACE_EVENT(rcu_utilization,
 	TP_printk("%s", __entry->s)
 );
 
-#ifdef CONFIG_RCU_TRACE
-
 #if defined(CONFIG_TREE_RCU) || defined(CONFIG_PREEMPT_RCU)
 
 /*
@@ -62,7 +66,7 @@ TRACE_EVENT(rcu_utilization,
  *	"end": End a grace period.
  *	"cpuend": CPU first notices a grace-period end.
  */
-TRACE_EVENT(rcu_grace_period,
+TRACE_EVENT_RCU(rcu_grace_period,
 
 	TP_PROTO(const char *rcuname, unsigned long gp_seq, const char *gpevent),
 
@@ -101,7 +105,7 @@ TRACE_EVENT(rcu_grace_period,
  * "Cleanup": Clean up rcu_node structure after previous GP.
  * "CleanupMore": Clean up, and another GP is needed.
  */
-TRACE_EVENT(rcu_future_grace_period,
+TRACE_EVENT_RCU(rcu_future_grace_period,
 
 	TP_PROTO(const char *rcuname, unsigned long gp_seq,
 		 unsigned long gp_seq_req, u8 level, int grplo, int grphi,
@@ -141,7 +145,7 @@ TRACE_EVENT(rcu_future_grace_period,
  * rcu_node structure, and the mask of CPUs that will be waited for.
  * All but the type of RCU are extracted from the rcu_node structure.
  */
-TRACE_EVENT(rcu_grace_period_init,
+TRACE_EVENT_RCU(rcu_grace_period_init,
 
 	TP_PROTO(const char *rcuname, unsigned long gp_seq, u8 level,
 		 int grplo, int grphi, unsigned long qsmask),
@@ -186,7 +190,7 @@ TRACE_EVENT(rcu_grace_period_init,
  *	"endwake": Woke piggybackers up.
  *	"done": Someone else did the expedited grace period for us.
  */
-TRACE_EVENT(rcu_exp_grace_period,
+TRACE_EVENT_RCU(rcu_exp_grace_period,
 
 	TP_PROTO(const char *rcuname, unsigned long gpseq, const char *gpevent),
 
@@ -218,7 +222,7 @@ TRACE_EVENT(rcu_exp_grace_period,
  *	"nxtlvl": Advance to next level of rcu_node funnel
  *	"wait": Wait for someone else to do expedited GP
  */
-TRACE_EVENT(rcu_exp_funnel_lock,
+TRACE_EVENT_RCU(rcu_exp_funnel_lock,
 
 	TP_PROTO(const char *rcuname, u8 level, int grplo, int grphi,
 		 const char *gpevent),
@@ -269,7 +273,7 @@ TRACE_EVENT(rcu_exp_funnel_lock,
  *	"WaitQueue": Enqueue partially done, timed wait for it to complete.
  *	"WokeQueue": Partial enqueue now complete.
  */
-TRACE_EVENT(rcu_nocb_wake,
+TRACE_EVENT_RCU(rcu_nocb_wake,
 
 	TP_PROTO(const char *rcuname, int cpu, const char *reason),
 
@@ -297,7 +301,7 @@ TRACE_EVENT(rcu_nocb_wake,
  * include SRCU), the grace-period number that the task is blocking
  * (the current or the next), and the task's PID.
  */
-TRACE_EVENT(rcu_preempt_task,
+TRACE_EVENT_RCU(rcu_preempt_task,
 
 	TP_PROTO(const char *rcuname, int pid, unsigned long gp_seq),
 
@@ -324,7 +328,7 @@ TRACE_EVENT(rcu_preempt_task,
  * read-side critical section exiting that critical section.  Track the
  * type of RCU (which one day might include SRCU) and the task's PID.
  */
-TRACE_EVENT(rcu_unlock_preempted_task,
+TRACE_EVENT_RCU(rcu_unlock_preempted_task,
 
 	TP_PROTO(const char *rcuname, unsigned long gp_seq, int pid),
 
@@ -353,7 +357,7 @@ TRACE_EVENT(rcu_unlock_preempted_task,
  * whether there are any blocked tasks blocking the current grace period.
  * All but the type of RCU are extracted from the rcu_node structure.
  */
-TRACE_EVENT(rcu_quiescent_state_report,
+TRACE_EVENT_RCU(rcu_quiescent_state_report,
 
 	TP_PROTO(const char *rcuname, unsigned long gp_seq,
 		 unsigned long mask, unsigned long qsmask,
@@ -396,7 +400,7 @@ TRACE_EVENT(rcu_quiescent_state_report,
  * state, which can be "dti" for dyntick-idle mode or "kick" when kicking
  * a CPU that has been in dyntick-idle mode for too long.
  */
-TRACE_EVENT(rcu_fqs,
+TRACE_EVENT_RCU(rcu_fqs,
 
 	TP_PROTO(const char *rcuname, unsigned long gp_seq, int cpu, const char *qsevent),
 
@@ -436,7 +440,7 @@ TRACE_EVENT(rcu_fqs,
  * events use two separate counters, and that the "++=" and "--=" events
  * for irq/NMI will change the counter by two, otherwise by one.
  */
-TRACE_EVENT(rcu_dyntick,
+TRACE_EVENT_RCU(rcu_dyntick,
 
 	TP_PROTO(const char *polarity, long oldnesting, long newnesting, atomic_t dynticks),
 
@@ -468,7 +472,7 @@ TRACE_EVENT(rcu_dyntick,
  * number of lazy callbacks queued, and the fourth element is the
  * total number of callbacks queued.
  */
-TRACE_EVENT(rcu_callback,
+TRACE_EVENT_RCU(rcu_callback,
 
 	TP_PROTO(const char *rcuname, struct rcu_head *rhp, long qlen_lazy,
 		 long qlen),
@@ -504,7 +508,7 @@ TRACE_EVENT(rcu_callback,
  * the fourth argument is the number of lazy callbacks queued, and the
  * fifth argument is the total number of callbacks queued.
  */
-TRACE_EVENT(rcu_kfree_callback,
+TRACE_EVENT_RCU(rcu_kfree_callback,
 
 	TP_PROTO(const char *rcuname, struct rcu_head *rhp, unsigned long offset,
 		 long qlen_lazy, long qlen),
@@ -539,7 +543,7 @@ TRACE_EVENT(rcu_kfree_callback,
  * the total number of callbacks queued, and the fourth argument is
  * the current RCU-callback batch limit.
  */
-TRACE_EVENT(rcu_batch_start,
+TRACE_EVENT_RCU(rcu_batch_start,
 
 	TP_PROTO(const char *rcuname, long qlen_lazy, long qlen, long blimit),
 
@@ -569,7 +573,7 @@ TRACE_EVENT(rcu_batch_start,
  * The first argument is the type of RCU, and the second argument is
  * a pointer to the RCU callback itself.
  */
-TRACE_EVENT(rcu_invoke_callback,
+TRACE_EVENT_RCU(rcu_invoke_callback,
 
 	TP_PROTO(const char *rcuname, struct rcu_head *rhp),
 
@@ -598,7 +602,7 @@ TRACE_EVENT(rcu_invoke_callback,
  * is the offset of the callback within the enclosing RCU-protected
  * data structure.
  */
-TRACE_EVENT(rcu_invoke_kfree_callback,
+TRACE_EVENT_RCU(rcu_invoke_kfree_callback,
 
 	TP_PROTO(const char *rcuname, struct rcu_head *rhp, unsigned long offset),
 
@@ -631,7 +635,7 @@ TRACE_EVENT(rcu_invoke_kfree_callback,
  * and the sixth argument (risk) is the return value from
  * rcu_is_callbacks_kthread().
  */
-TRACE_EVENT(rcu_batch_end,
+TRACE_EVENT_RCU(rcu_batch_end,
 
 	TP_PROTO(const char *rcuname, int callbacks_invoked,
 		 char cb, char nr, char iit, char risk),
@@ -673,7 +677,7 @@ TRACE_EVENT(rcu_batch_end,
  * callback address can be NULL.
  */
 #define RCUTORTURENAME_LEN 8
-TRACE_EVENT(rcu_torture_read,
+TRACE_EVENT_RCU(rcu_torture_read,
 
 	TP_PROTO(const char *rcutorturename, struct rcu_head *rhp,
 		 unsigned long secs, unsigned long c_old, unsigned long c),
@@ -721,7 +725,7 @@ TRACE_EVENT(rcu_torture_read,
  * The "cpu" argument is the CPU or -1 if meaningless, the "cnt" argument
  * is the count of remaining callbacks, and "done" is the piggybacking count.
  */
-TRACE_EVENT(rcu_barrier,
+TRACE_EVENT_RCU(rcu_barrier,
 
 	TP_PROTO(const char *rcuname, const char *s, int cpu, int cnt, unsigned long done),
 
@@ -748,41 +752,6 @@ TRACE_EVENT(rcu_barrier,
 		  __entry->done)
 );
 
-#else /* #ifdef CONFIG_RCU_TRACE */
-
-#define trace_rcu_grace_period(rcuname, gp_seq, gpevent) do { } while (0)
-#define trace_rcu_future_grace_period(rcuname, gp_seq, gp_seq_req, \
-				      level, grplo, grphi, event) \
-				      do { } while (0)
-#define trace_rcu_grace_period_init(rcuname, gp_seq, level, grplo, grphi, \
-				    qsmask) do { } while (0)
-#define trace_rcu_exp_grace_period(rcuname, gqseq, gpevent) \
-	do { } while (0)
-#define trace_rcu_exp_funnel_lock(rcuname, level, grplo, grphi, gpevent) \
-	do { } while (0)
-#define trace_rcu_nocb_wake(rcuname, cpu, reason) do { } while (0)
-#define trace_rcu_preempt_task(rcuname, pid, gp_seq) do { } while (0)
-#define trace_rcu_unlock_preempted_task(rcuname, gp_seq, pid) do { } while (0)
-#define trace_rcu_quiescent_state_report(rcuname, gp_seq, mask, qsmask, level, \
-					 grplo, grphi, gp_tasks) do { } \
-	while (0)
-#define trace_rcu_fqs(rcuname, gp_seq, cpu, qsevent) do { } while (0)
-#define trace_rcu_dyntick(polarity, oldnesting, newnesting, dyntick) do { } while (0)
-#define trace_rcu_callback(rcuname, rhp, qlen_lazy, qlen) do { } while (0)
-#define trace_rcu_kfree_callback(rcuname, rhp, offset, qlen_lazy, qlen) \
-	do { } while (0)
-#define trace_rcu_batch_start(rcuname, qlen_lazy, qlen, blimit) \
-	do { } while (0)
-#define trace_rcu_invoke_callback(rcuname, rhp) do { } while (0)
-#define trace_rcu_invoke_kfree_callback(rcuname, rhp, offset) do { } while (0)
-#define trace_rcu_batch_end(rcuname, callbacks_invoked, cb, nr, iit, risk) \
-	do { } while (0)
-#define trace_rcu_torture_read(rcutorturename, rhp, secs, c_old, c) \
-	do { } while (0)
-#define trace_rcu_barrier(name, s, cpu, cnt, done) do { } while (0)
-
-#endif /* #else #ifdef CONFIG_RCU_TRACE */
-
 #endif /* _TRACE_RCU_H */
 
 /* This part must be outside protection */

include/trace/events/sched.h

@@ -242,7 +242,6 @@ DEFINE_EVENT(sched_process_template, sched_process_free,
 	     TP_PROTO(struct task_struct *p),
 	     TP_ARGS(p));
 
-
 /*
  * Tracepoint for a task exiting:
  */
@@ -336,11 +335,20 @@ TRACE_EVENT(sched_process_exec,
 		  __entry->pid, __entry->old_pid)
 );
 
+
+#ifdef CONFIG_SCHEDSTATS
+#define DEFINE_EVENT_SCHEDSTAT DEFINE_EVENT
+#define DECLARE_EVENT_CLASS_SCHEDSTAT DECLARE_EVENT_CLASS
+#else
+#define DEFINE_EVENT_SCHEDSTAT DEFINE_EVENT_NOP
+#define DECLARE_EVENT_CLASS_SCHEDSTAT DECLARE_EVENT_CLASS_NOP
+#endif
+
 /*
  * XXX the below sched_stat tracepoints only apply to SCHED_OTHER/BATCH/IDLE
  *     adding sched_stat support to SCHED_FIFO/RR would be welcome.
  */
-DECLARE_EVENT_CLASS(sched_stat_template,
+DECLARE_EVENT_CLASS_SCHEDSTAT(sched_stat_template,
 
 	TP_PROTO(struct task_struct *tsk, u64 delay),
 
@@ -363,12 +371,11 @@ DECLARE_EVENT_CLASS(sched_stat_template,
 			(unsigned long long)__entry->delay)
 );
 
-
 /*
  * Tracepoint for accounting wait time (time the task is runnable
  * but not actually running due to scheduler contention).
  */
-DEFINE_EVENT(sched_stat_template, sched_stat_wait,
+DEFINE_EVENT_SCHEDSTAT(sched_stat_template, sched_stat_wait,
 	     TP_PROTO(struct task_struct *tsk, u64 delay),
 	     TP_ARGS(tsk, delay));
 
@@ -376,7 +383,7 @@ DEFINE_EVENT(sched_stat_template, sched_stat_wait,
  * Tracepoint for accounting sleep time (time the task is not runnable,
  * including iowait, see below).
  */
-DEFINE_EVENT(sched_stat_template, sched_stat_sleep,
+DEFINE_EVENT_SCHEDSTAT(sched_stat_template, sched_stat_sleep,
 	     TP_PROTO(struct task_struct *tsk, u64 delay),
 	     TP_ARGS(tsk, delay));
 
@@ -384,14 +391,14 @@ DEFINE_EVENT(sched_stat_template, sched_stat_sleep,
  * Tracepoint for accounting iowait time (time the task is not runnable
  * due to waiting on IO to complete).
  */
-DEFINE_EVENT(sched_stat_template, sched_stat_iowait,
+DEFINE_EVENT_SCHEDSTAT(sched_stat_template, sched_stat_iowait,
 	     TP_PROTO(struct task_struct *tsk, u64 delay),
 	     TP_ARGS(tsk, delay));
 
 /*
  * Tracepoint for accounting blocked time (time the task is in uninterruptible).
  */
-DEFINE_EVENT(sched_stat_template, sched_stat_blocked,
+DEFINE_EVENT_SCHEDSTAT(sched_stat_template, sched_stat_blocked,
 	     TP_PROTO(struct task_struct *tsk, u64 delay),
 	     TP_ARGS(tsk, delay));
 

kernel/livepatch/core.c

@@ -1208,14 +1208,6 @@ void klp_module_going(struct module *mod)
 
 static int __init klp_init(void)
 {
-	int ret;
-
-	ret = klp_check_compiler_support();
-	if (ret) {
-		pr_info("Your compiler is too old; turning off.\n");
-		return -EINVAL;
-	}
-
 	klp_root_kobj = kobject_create_and_add("livepatch", kernel_kobj);
 	if (!klp_root_kobj)
 		return -ENOMEM;

kernel/rcu/rcu.h

@@ -11,11 +11,6 @@
 #define __LINUX_RCU_H
 
 #include <trace/events/rcu.h>
-#ifdef CONFIG_RCU_TRACE
-#define RCU_TRACE(stmt) stmt
-#else /* #ifdef CONFIG_RCU_TRACE */
-#define RCU_TRACE(stmt)
-#endif /* #else #ifdef CONFIG_RCU_TRACE */
 
 /* Offset to allow distinguishing irq vs. task-based idle entry/exit. */
 #define DYNTICK_IRQ_NONIDLE	((LONG_MAX / 2) + 1)
@@ -216,12 +211,12 @@ static inline bool __rcu_reclaim(const char *rn, struct rcu_head *head)
 
 	rcu_lock_acquire(&rcu_callback_map);
 	if (__is_kfree_rcu_offset(offset)) {
-		RCU_TRACE(trace_rcu_invoke_kfree_callback(rn, head, offset);)
+		trace_rcu_invoke_kfree_callback(rn, head, offset);
 		kfree((void *)head - offset);
 		rcu_lock_release(&rcu_callback_map);
 		return true;
 	} else {
-		RCU_TRACE(trace_rcu_invoke_callback(rn, head);)
+		trace_rcu_invoke_callback(rn, head);
 		f = head->func;
 		WRITE_ONCE(head->func, (rcu_callback_t)0L);
 		f(head);

kernel/rcu/tree.c

@@ -1969,14 +1969,14 @@ rcu_check_quiescent_state(struct rcu_data *rdp)
  */
 int rcutree_dying_cpu(unsigned int cpu)
 {
-	RCU_TRACE(bool blkd;)
-	RCU_TRACE(struct rcu_data *rdp = this_cpu_ptr(&rcu_data);)
-	RCU_TRACE(struct rcu_node *rnp = rdp->mynode;)
+	bool blkd;
+	struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
+	struct rcu_node *rnp = rdp->mynode;
 
 	if (!IS_ENABLED(CONFIG_HOTPLUG_CPU))
 		return 0;
 
-	RCU_TRACE(blkd = !!(rnp->qsmask & rdp->grpmask);)
+	blkd = !!(rnp->qsmask & rdp->grpmask);
 	trace_rcu_grace_period(rcu_state.name, rnp->gp_seq,
 			       blkd ? TPS("cpuofl") : TPS("cpuofl-bgp"));
 	return 0;

kernel/trace/ftrace.c

@@ -70,12 +70,8 @@
 #define INIT_OPS_HASH(opsname)	\
 	.func_hash		= &opsname.local_hash,			\
 	.local_hash.regex_lock	= __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
-#define ASSIGN_OPS_HASH(opsname, val) \
-	.func_hash		= val, \
-	.local_hash.regex_lock	= __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
 #else
 #define INIT_OPS_HASH(opsname)
-#define ASSIGN_OPS_HASH(opsname, val)
 #endif
 
 enum {
@@ -3880,7 +3876,7 @@ static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
 static bool module_exists(const char *module)
 {
 	/* All modules have the symbol __this_module */
-	const char this_mod[] = "__this_module";
+	static const char this_mod[] = "__this_module";
 	char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
 	unsigned long val;
 	int n;
@@ -6265,6 +6261,9 @@ __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
 	preempt_disable_notrace();
 
 	do_for_each_ftrace_op(op, ftrace_ops_list) {
+		/* Stub functions don't need to be called nor tested */
+		if (op->flags & FTRACE_OPS_FL_STUB)
+			continue;
 		/*
 		 * Check the following for each ops before calling their func:
 		 *  if RCU flag is set, then rcu_is_watching() must be true

kernel/trace/ring_buffer.c

@@ -4979,7 +4979,7 @@ static __init int rb_write_something(struct rb_test_data *data, bool nested)
 	cnt = data->cnt + (nested ? 27 : 0);
 
 	/* Multiply cnt by ~e, to make some unique increment */
-	size = (data->cnt * 68 / 25) % (sizeof(rb_string) - 1);
+	size = (cnt * 68 / 25) % (sizeof(rb_string) - 1);
 
 	len = size + sizeof(struct rb_item);
 

kernel/trace/ring_buffer_benchmark.c

@@ -362,7 +362,7 @@ static void ring_buffer_producer(void)
 			hit--; /* make it non zero */
 		}
 
-		/* Caculate the average time in nanosecs */
+		/* Calculate the average time in nanosecs */
 		avg = NSEC_PER_MSEC / (hit + missed);
 		trace_printk("%ld ns per entry\n", avg);
 	}

kernel/trace/trace.h

@@ -293,11 +293,13 @@ struct trace_array {
 	int			nr_topts;
 	bool			clear_trace;
 	int			buffer_percent;
+	unsigned int		n_err_log_entries;
 	struct tracer		*current_trace;
 	unsigned int		trace_flags;
 	unsigned char		trace_flags_index[TRACE_FLAGS_MAX_SIZE];
 	unsigned int		flags;
 	raw_spinlock_t		start_lock;
+	struct list_head	err_log;
 	struct dentry		*dir;
 	struct dentry		*options;
 	struct dentry		*percpu_dir;
@@ -719,6 +721,9 @@ void trace_init_global_iter(struct trace_iterator *iter);
 
 void tracing_iter_reset(struct trace_iterator *iter, int cpu);
 
+unsigned long trace_total_entries_cpu(struct trace_array *tr, int cpu);
+unsigned long trace_total_entries(struct trace_array *tr);
+
 void trace_function(struct trace_array *tr,
 		    unsigned long ip,
 		    unsigned long parent_ip,
@@ -1545,7 +1550,8 @@ extern int apply_subsystem_event_filter(struct trace_subsystem_dir *dir,
 extern void print_subsystem_event_filter(struct event_subsystem *system,
 					 struct trace_seq *s);
 extern int filter_assign_type(const char *type);
-extern int create_event_filter(struct trace_event_call *call,
+extern int create_event_filter(struct trace_array *tr,
+			       struct trace_event_call *call,
 			       char *filter_str, bool set_str,
 			       struct event_filter **filterp);
 extern void free_event_filter(struct event_filter *filter);
@@ -1876,6 +1882,11 @@ extern ssize_t trace_parse_run_command(struct file *file,
 		const char __user *buffer, size_t count, loff_t *ppos,
 		int (*createfn)(int, char**));
 
+extern unsigned int err_pos(char *cmd, const char *str);
+extern void tracing_log_err(struct trace_array *tr,
+			    const char *loc, const char *cmd,
+			    const char **errs, u8 type, u8 pos);
+
 /*
  * Normal trace_printk() and friends allocates special buffers
  * to do the manipulation, as well as saves the print formats

kernel/trace/trace_events.c

@@ -832,6 +832,7 @@ static int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
 
 	return ret;
 }
+EXPORT_SYMBOL_GPL(ftrace_set_clr_event);
 
 /**
  * trace_set_clr_event - enable or disable an event
@@ -1318,9 +1319,6 @@ event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
 	char buf[32];
 	int len;
 
-	if (*ppos)
-		return 0;
-
 	if (unlikely(!id))
 		return -ENODEV;
 

kernel/trace/trace_events_filter.c

@@ -66,7 +66,8 @@ static const char * ops[] = { OPS };
 	C(INVALID_FILTER,	"Meaningless filter expression"),	\
 	C(IP_FIELD_ONLY,	"Only 'ip' field is supported for function trace"), \
 	C(INVALID_VALUE,	"Invalid value (did you forget quotes)?"), \
-	C(NO_FILTER,		"No filter found"),
+	C(ERRNO,		"Error"),				\
+	C(NO_FILTER,		"No filter found")
 
 #undef C
 #define C(a, b)		FILT_ERR_##a
@@ -76,7 +77,7 @@ enum { ERRORS };
 #undef C
 #define C(a, b)		b
 
-static char *err_text[] = { ERRORS };
+static const char *err_text[] = { ERRORS };
 
 /* Called after a '!' character but "!=" and "!~" are not "not"s */
 static bool is_not(const char *str)
@@ -919,7 +920,8 @@ static void remove_filter_string(struct event_filter *filter)
 	filter->filter_string = NULL;
 }
 
-static void append_filter_err(struct filter_parse_error *pe,
+static void append_filter_err(struct trace_array *tr,
+			      struct filter_parse_error *pe,
 			      struct event_filter *filter)
 {
 	struct trace_seq *s;
@@ -947,8 +949,14 @@ static void append_filter_err(struct filter_parse_error *pe,
 	if (pe->lasterr > 0) {
 		trace_seq_printf(s, "\n%*s", pos, "^");
 		trace_seq_printf(s, "\nparse_error: %s\n", err_text[pe->lasterr]);
+		tracing_log_err(tr, "event filter parse error",
+				filter->filter_string, err_text,
+				pe->lasterr, pe->lasterr_pos);
 	} else {
 		trace_seq_printf(s, "\nError: (%d)\n", pe->lasterr);
+		tracing_log_err(tr, "event filter parse error",
+				filter->filter_string, err_text,
+				FILT_ERR_ERRNO, 0);
 	}
 	trace_seq_putc(s, 0);
 	buf = kmemdup_nul(s->buffer, s->seq.len, GFP_KERNEL);
@@ -1600,7 +1608,7 @@ static int process_system_preds(struct trace_subsystem_dir *dir,
 		if (err) {
 			filter_disable(file);
 			parse_error(pe, FILT_ERR_BAD_SUBSYS_FILTER, 0);
-			append_filter_err(pe, filter);
+			append_filter_err(tr, pe, filter);
 		} else
 			event_set_filtered_flag(file);
 
@@ -1712,7 +1720,8 @@ static void create_filter_finish(struct filter_parse_error *pe)
  * information if @set_str is %true and the caller is responsible for
  * freeing it.
  */
-static int create_filter(struct trace_event_call *call,
+static int create_filter(struct trace_array *tr,
+			 struct trace_event_call *call,
 			 char *filter_string, bool set_str,
 			 struct event_filter **filterp)
 {
@@ -1729,17 +1738,18 @@ static int create_filter(struct trace_event_call *call,
 
 	err = process_preds(call, filter_string, *filterp, pe);
 	if (err && set_str)
-		append_filter_err(pe, *filterp);
+		append_filter_err(tr, pe, *filterp);
 	create_filter_finish(pe);
 
 	return err;
 }
 
-int create_event_filter(struct trace_event_call *call,
+int create_event_filter(struct trace_array *tr,
+			struct trace_event_call *call,
 			char *filter_str, bool set_str,
 			struct event_filter **filterp)
 {
-	return create_filter(call, filter_str, set_str, filterp);
+	return create_filter(tr, call, filter_str, set_str, filterp);
 }
 
 /**
@@ -1766,7 +1776,7 @@ static int create_system_filter(struct trace_subsystem_dir *dir,
 			kfree((*filterp)->filter_string);
 			(*filterp)->filter_string = NULL;
 		} else {
-			append_filter_err(pe, *filterp);
+			append_filter_err(tr, pe, *filterp);
 		}
 	}
 	create_filter_finish(pe);
@@ -1797,7 +1807,7 @@ int apply_event_filter(struct trace_event_file *file, char *filter_string)
 		return 0;
 	}
 
-	err = create_filter(call, filter_string, true, &filter);
+	err = create_filter(file->tr, call, filter_string, true, &filter);
 
 	/*
 	 * Always swap the call filter with the new filter
@@ -2053,7 +2063,7 @@ int ftrace_profile_set_filter(struct perf_event *event, int event_id,
 	if (event->filter)
 		goto out_unlock;
 
-	err = create_filter(call, filter_str, false, &filter);
+	err = create_filter(NULL, call, filter_str, false, &filter);
 	if (err)
 		goto free_filter;
 
@@ -2202,8 +2212,8 @@ static __init int ftrace_test_event_filter(void)
 		struct test_filter_data_t *d = &test_filter_data[i];
 		int err;
 
-		err = create_filter(&event_ftrace_test_filter, d->filter,
-				    false, &filter);
+		err = create_filter(NULL, &event_ftrace_test_filter,
+				    d->filter, false, &filter);
 		if (err) {
 			printk(KERN_INFO
 			       "Failed to get filter for '%s', err %d\n",

kernel/trace/trace_events_trigger.c

@@ -731,7 +731,8 @@ int set_trigger_filter(char *filter_str,
 		goto out;
 
 	/* The filter is for the 'trigger' event, not the triggered event */
-	ret = create_event_filter(file->event_call, filter_str, false, &filter);
+	ret = create_event_filter(file->tr, file->event_call,
+				  filter_str, false, &filter);
 	/*
 	 * If create_event_filter() fails, filter still needs to be freed.
 	 * Which the calling code will do with data->filter.

kernel/trace/trace_kdb.c

@@ -17,29 +17,25 @@
 #include "trace.h"
 #include "trace_output.h"
 
-static void ftrace_dump_buf(int skip_lines, long cpu_file)
+static struct trace_iterator iter;
+static struct ring_buffer_iter *buffer_iter[CONFIG_NR_CPUS];
+
+static void ftrace_dump_buf(int skip_entries, long cpu_file)
 {
-	/* use static because iter can be a bit big for the stack */
-	static struct trace_iterator iter;
-	static struct ring_buffer_iter *buffer_iter[CONFIG_NR_CPUS];
 	struct trace_array *tr;
 	unsigned int old_userobj;
 	int cnt = 0, cpu;
 
-	trace_init_global_iter(&iter);
-	iter.buffer_iter = buffer_iter;
 	tr = iter.tr;
 
-	for_each_tracing_cpu(cpu) {
-		atomic_inc(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
-	}
-
 	old_userobj = tr->trace_flags;
 
 	/* don't look at user memory in panic mode */
 	tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
 
 	kdb_printf("Dumping ftrace buffer:\n");
+	if (skip_entries)
+		kdb_printf("(skipping %d entries)\n", skip_entries);
 
 	/* reset all but tr, trace, and overruns */
 	memset(&iter.seq, 0,
@@ -70,11 +66,11 @@ static void ftrace_dump_buf(int skip_lines, long cpu_file)
 			kdb_printf("---------------------------------\n");
 		cnt++;
 
-		if (!skip_lines) {
+		if (!skip_entries) {
 			print_trace_line(&iter);
 			trace_printk_seq(&iter.seq);
 		} else {
-			skip_lines--;
+			skip_entries--;
 		}
 
 		if (KDB_FLAG(CMD_INTERRUPT))
@@ -89,10 +85,6 @@ static void ftrace_dump_buf(int skip_lines, long cpu_file)
 out:
 	tr->trace_flags = old_userobj;
 
-	for_each_tracing_cpu(cpu) {
-		atomic_dec(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
-	}
-
 	for_each_tracing_cpu(cpu) {
 		if (iter.buffer_iter[cpu]) {
 			ring_buffer_read_finish(iter.buffer_iter[cpu]);
@@ -106,17 +98,19 @@ static void ftrace_dump_buf(int skip_lines, long cpu_file)
  */
 static int kdb_ftdump(int argc, const char **argv)
 {
-	int skip_lines = 0;
+	int skip_entries = 0;
 	long cpu_file;
 	char *cp;
+	int cnt;
+	int cpu;
 
 	if (argc > 2)
 		return KDB_ARGCOUNT;
 
 	if (argc) {
-		skip_lines = simple_strtol(argv[1], &cp, 0);
+		skip_entries = simple_strtol(argv[1], &cp, 0);
 		if (*cp)
-			skip_lines = 0;
+			skip_entries = 0;
 	}
 
 	if (argc == 2) {
@@ -129,7 +123,29 @@ static int kdb_ftdump(int argc, const char **argv)
 	}
 
 	kdb_trap_printk++;
-	ftrace_dump_buf(skip_lines, cpu_file);
+
+	trace_init_global_iter(&iter);
+	iter.buffer_iter = buffer_iter;
+
+	for_each_tracing_cpu(cpu) {
+		atomic_inc(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
+	}
+
+	/* A negative skip_entries means skip all but the last entries */
+	if (skip_entries < 0) {
+		if (cpu_file == RING_BUFFER_ALL_CPUS)
+			cnt = trace_total_entries(NULL);
+		else
+			cnt = trace_total_entries_cpu(NULL, cpu_file);
+		skip_entries = max(cnt + skip_entries, 0);
+	}
+
+	ftrace_dump_buf(skip_entries, cpu_file);
+
+	for_each_tracing_cpu(cpu) {
+		atomic_dec(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
+	}
+
 	kdb_trap_printk--;
 
 	return 0;
@@ -137,8 +153,9 @@ static int kdb_ftdump(int argc, const char **argv)
 
 static __init int kdb_ftrace_register(void)
 {
-	kdb_register_flags("ftdump", kdb_ftdump, "[skip_#lines] [cpu]",
-			    "Dump ftrace log", 0, KDB_ENABLE_ALWAYS_SAFE);
+	kdb_register_flags("ftdump", kdb_ftdump, "[skip_#entries] [cpu]",
+			    "Dump ftrace log; -skip dumps last #entries", 0,
+			    KDB_ENABLE_ALWAYS_SAFE);
 	return 0;
 }
 

kernel/trace/trace_kprobe.c

@@ -441,13 +441,8 @@ static int __register_trace_kprobe(struct trace_kprobe *tk)
 	else
 		ret = register_kprobe(&tk->rp.kp);
 
-	if (ret == 0) {
+	if (ret == 0)
 		tk->tp.flags |= TP_FLAG_REGISTERED;
-	} else if (ret == -EILSEQ) {
-		pr_warn("Probing address(0x%p) is not an instruction boundary.\n",
-			tk->rp.kp.addr);
-		ret = -EINVAL;
-	}
 	return ret;
 }
 
@@ -591,7 +586,7 @@ static int trace_kprobe_create(int argc, const char *argv[])
 	 * Type of args:
 	 *  FETCHARG:TYPE : use TYPE instead of unsigned long.
 	 */
-	struct trace_kprobe *tk;
+	struct trace_kprobe *tk = NULL;
 	int i, len, ret = 0;
 	bool is_return = false;
 	char *symbol = NULL, *tmp = NULL;
@@ -615,44 +610,50 @@ static int trace_kprobe_create(int argc, const char *argv[])
 	if (argc < 2)
 		return -ECANCELED;
 
+	trace_probe_log_init("trace_kprobe", argc, argv);
+
 	event = strchr(&argv[0][1], ':');
 	if (event)
 		event++;
 
 	if (isdigit(argv[0][1])) {
 		if (!is_return) {
-			pr_info("Maxactive is not for kprobe");
-			return -EINVAL;
+			trace_probe_log_err(1, MAXACT_NO_KPROBE);
+			goto parse_error;
 		}
 		if (event)
 			len = event - &argv[0][1] - 1;
 		else
 			len = strlen(&argv[0][1]);
-		if (len > MAX_EVENT_NAME_LEN - 1)
-			return -E2BIG;
+		if (len > MAX_EVENT_NAME_LEN - 1) {
+			trace_probe_log_err(1, BAD_MAXACT);
+			goto parse_error;
+		}
 		memcpy(buf, &argv[0][1], len);
 		buf[len] = '\0';
 		ret = kstrtouint(buf, 0, &maxactive);
 		if (ret || !maxactive) {
-			pr_info("Invalid maxactive number\n");
-			return ret;
+			trace_probe_log_err(1, BAD_MAXACT);
+			goto parse_error;
 		}
 		/* kretprobes instances are iterated over via a list. The
 		 * maximum should stay reasonable.
 		 */
 		if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
-			pr_info("Maxactive is too big (%d > %d).\n",
-				maxactive, KRETPROBE_MAXACTIVE_MAX);
-			return -E2BIG;
+			trace_probe_log_err(1, MAXACT_TOO_BIG);
+			goto parse_error;
 		}
 	}
 
 	/* try to parse an address. if that fails, try to read the
 	 * input as a symbol. */
 	if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
+		trace_probe_log_set_index(1);
 		/* Check whether uprobe event specified */
-		if (strchr(argv[1], '/') && strchr(argv[1], ':'))
-			return -ECANCELED;
+		if (strchr(argv[1], '/') && strchr(argv[1], ':')) {
+			ret = -ECANCELED;
+			goto error;
+		}
 		/* a symbol specified */
 		symbol = kstrdup(argv[1], GFP_KERNEL);
 		if (!symbol)
@@ -660,23 +661,23 @@ static int trace_kprobe_create(int argc, const char *argv[])
 		/* TODO: support .init module functions */
 		ret = traceprobe_split_symbol_offset(symbol, &offset);
 		if (ret || offset < 0 || offset > UINT_MAX) {
-			pr_info("Failed to parse either an address or a symbol.\n");
-			goto out;
+			trace_probe_log_err(0, BAD_PROBE_ADDR);
+			goto parse_error;
 		}
 		if (kprobe_on_func_entry(NULL, symbol, offset))
 			flags |= TPARG_FL_FENTRY;
 		if (offset && is_return && !(flags & TPARG_FL_FENTRY)) {
-			pr_info("Given offset is not valid for return probe.\n");
-			ret = -EINVAL;
-			goto out;
+			trace_probe_log_err(0, BAD_RETPROBE);
+			goto parse_error;
 		}
 	}
-	argc -= 2; argv += 2;
 
+	trace_probe_log_set_index(0);
 	if (event) {
-		ret = traceprobe_parse_event_name(&event, &group, buf);
+		ret = traceprobe_parse_event_name(&event, &group, buf,
+						  event - argv[0]);
 		if (ret)
-			goto out;
+			goto parse_error;
 	} else {
 		/* Make a new event name */
 		if (symbol)
@@ -691,13 +692,14 @@ static int trace_kprobe_create(int argc, const char *argv[])
 
 	/* setup a probe */
 	tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
-			       argc, is_return);
+			       argc - 2, is_return);
 	if (IS_ERR(tk)) {
 		ret = PTR_ERR(tk);
-		/* This must return -ENOMEM otherwise there is a bug */
+		/* This must return -ENOMEM, else there is a bug */
 		WARN_ON_ONCE(ret != -ENOMEM);
-		goto out;
+		goto out;	/* We know tk is not allocated */
 	}
+	argc -= 2; argv += 2;
 
 	/* parse arguments */
 	for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
@@ -707,19 +709,32 @@ static int trace_kprobe_create(int argc, const char *argv[])
 			goto error;
 		}
 
+		trace_probe_log_set_index(i + 2);
 		ret = traceprobe_parse_probe_arg(&tk->tp, i, tmp, flags);
 		kfree(tmp);
 		if (ret)
-			goto error;
+			goto error;	/* This can be -ENOMEM */
 	}
 
 	ret = register_trace_kprobe(tk);
-	if (ret)
+	if (ret) {
+		trace_probe_log_set_index(1);
+		if (ret == -EILSEQ)
+			trace_probe_log_err(0, BAD_INSN_BNDRY);
+		else if (ret == -ENOENT)
+			trace_probe_log_err(0, BAD_PROBE_ADDR);
+		else if (ret != -ENOMEM)
+			trace_probe_log_err(0, FAIL_REG_PROBE);
 		goto error;
+	}
+
 out:
+	trace_probe_log_clear();
 	kfree(symbol);
 	return ret;
 
+parse_error:
+	ret = -EINVAL;
 error:
 	free_trace_kprobe(tk);
 	goto out;

kernel/trace/trace_probe.h

@@ -124,6 +124,7 @@ struct fetch_insn {
 
 /* fetch + deref*N + store + mod + end <= 16, this allows N=12, enough */
 #define FETCH_INSN_MAX	16
+#define FETCH_TOKEN_COMM	(-ECOMM)
 
 /* Fetch type information table */
 struct fetch_type {
@@ -280,8 +281,8 @@ extern int traceprobe_update_arg(struct probe_arg *arg);
 extern void traceprobe_free_probe_arg(struct probe_arg *arg);
 
 extern int traceprobe_split_symbol_offset(char *symbol, long *offset);
-extern int traceprobe_parse_event_name(const char **pevent,
-				       const char **pgroup, char *buf);
+int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
+				char *buf, int offset);
 
 extern int traceprobe_set_print_fmt(struct trace_probe *tp, bool is_return);
 
@@ -298,3 +299,76 @@ extern void destroy_local_trace_uprobe(struct trace_event_call *event_call);
 #endif
 extern int traceprobe_define_arg_fields(struct trace_event_call *event_call,
 					size_t offset, struct trace_probe *tp);
+
+#undef ERRORS
+#define ERRORS	\
+	C(FILE_NOT_FOUND,	"Failed to find the given file"),	\
+	C(NO_REGULAR_FILE,	"Not a regular file"),			\
+	C(BAD_REFCNT,		"Invalid reference counter offset"),	\
+	C(REFCNT_OPEN_BRACE,	"Reference counter brace is not closed"), \
+	C(BAD_REFCNT_SUFFIX,	"Reference counter has wrong suffix"),	\
+	C(BAD_UPROBE_OFFS,	"Invalid uprobe offset"),		\
+	C(MAXACT_NO_KPROBE,	"Maxactive is not for kprobe"),		\
+	C(BAD_MAXACT,		"Invalid maxactive number"),		\
+	C(MAXACT_TOO_BIG,	"Maxactive is too big"),		\
+	C(BAD_PROBE_ADDR,	"Invalid probed address or symbol"),	\
+	C(BAD_RETPROBE,		"Retprobe address must be an function entry"), \
+	C(NO_GROUP_NAME,	"Group name is not specified"),		\
+	C(GROUP_TOO_LONG,	"Group name is too long"),		\
+	C(BAD_GROUP_NAME,	"Group name must follow the same rules as C identifiers"), \
+	C(NO_EVENT_NAME,	"Event name is not specified"),		\
+	C(EVENT_TOO_LONG,	"Event name is too long"),		\
+	C(BAD_EVENT_NAME,	"Event name must follow the same rules as C identifiers"), \
+	C(RETVAL_ON_PROBE,	"$retval is not available on probe"),	\
+	C(BAD_STACK_NUM,	"Invalid stack number"),		\
+	C(BAD_ARG_NUM,		"Invalid argument number"),		\
+	C(BAD_VAR,		"Invalid $-valiable specified"),	\
+	C(BAD_REG_NAME,		"Invalid register name"),		\
+	C(BAD_MEM_ADDR,		"Invalid memory address"),		\
+	C(FILE_ON_KPROBE,	"File offset is not available with kprobe"), \
+	C(BAD_FILE_OFFS,	"Invalid file offset value"),		\
+	C(SYM_ON_UPROBE,	"Symbol is not available with uprobe"),	\
+	C(TOO_MANY_OPS,		"Dereference is too much nested"), 	\
+	C(DEREF_NEED_BRACE,	"Dereference needs a brace"),		\
+	C(BAD_DEREF_OFFS,	"Invalid dereference offset"),		\
+	C(DEREF_OPEN_BRACE,	"Dereference brace is not closed"),	\
+	C(COMM_CANT_DEREF,	"$comm can not be dereferenced"),	\
+	C(BAD_FETCH_ARG,	"Invalid fetch argument"),		\
+	C(ARRAY_NO_CLOSE,	"Array is not closed"),			\
+	C(BAD_ARRAY_SUFFIX,	"Array has wrong suffix"),		\
+	C(BAD_ARRAY_NUM,	"Invalid array size"),			\
+	C(ARRAY_TOO_BIG,	"Array number is too big"),		\
+	C(BAD_TYPE,		"Unknown type is specified"),		\
+	C(BAD_STRING,		"String accepts only memory argument"),	\
+	C(BAD_BITFIELD,		"Invalid bitfield"),			\
+	C(ARG_NAME_TOO_LONG,	"Argument name is too long"),		\
+	C(NO_ARG_NAME,		"Argument name is not specified"),	\
+	C(BAD_ARG_NAME,		"Argument name must follow the same rules as C identifiers"), \
+	C(USED_ARG_NAME,	"This argument name is already used"),	\
+	C(ARG_TOO_LONG,		"Argument expression is too long"),	\
+	C(NO_ARG_BODY,		"No argument expression"),		\
+	C(BAD_INSN_BNDRY,	"Probe point is not an instruction boundary"),\
+	C(FAIL_REG_PROBE,	"Failed to register probe event"),
+
+#undef C
+#define C(a, b)		TP_ERR_##a
+
+/* Define TP_ERR_ */
+enum { ERRORS };
+
+/* Error text is defined in trace_probe.c */
+
+struct trace_probe_log {
+	const char	*subsystem;
+	const char	**argv;
+	int		argc;
+	int		index;
+};
+
+void trace_probe_log_init(const char *subsystem, int argc, const char **argv);
+void trace_probe_log_set_index(int index);
+void trace_probe_log_clear(void);
+void __trace_probe_log_err(int offset, int err);
+
+#define trace_probe_log_err(offs, err)	\
+	__trace_probe_log_err(offs, TP_ERR_##err)

kernel/trace/trace_probe_tmpl.h

@@ -88,7 +88,7 @@ process_fetch_insn_bottom(struct fetch_insn *code, unsigned long val,
 	/* 3rd stage: store value to buffer */
 	if (unlikely(!dest)) {
 		if (code->op == FETCH_OP_ST_STRING) {
-			ret += fetch_store_strlen(val + code->offset);
+			ret = fetch_store_strlen(val + code->offset);
 			code++;
 			goto array;
 		} else

kernel/trace/trace_selftest.c

@@ -792,7 +792,10 @@ trace_selftest_startup_function_graph(struct tracer *trace,
 	/* check the trace buffer */
 	ret = trace_test_buffer(&tr->trace_buffer, &count);
 
-	trace->reset(tr);
+	/* Need to also simulate the tr->reset to remove this fgraph_ops */
+	tracing_stop_cmdline_record();
+	unregister_ftrace_graph(&fgraph_ops);
+
 	tracing_start();
 
 	if (!ret && !count) {

kernel/trace/trace_uprobe.c

@@ -156,6 +156,9 @@ fetch_store_string(unsigned long addr, void *dest, void *base)
 	if (unlikely(!maxlen))
 		return -ENOMEM;
 
+	if (addr == FETCH_TOKEN_COMM)
+		ret = strlcpy(dst, current->comm, maxlen);
+	else
 		ret = strncpy_from_user(dst, src, maxlen);
 	if (ret >= 0) {
 		if (ret == maxlen)
@@ -180,6 +183,9 @@ fetch_store_strlen(unsigned long addr)
 	int len;
 	void __user *vaddr = (void __force __user *) addr;
 
+	if (addr == FETCH_TOKEN_COMM)
+		len = strlen(current->comm) + 1;
+	else
 		len = strnlen_user(vaddr, MAX_STRING_SIZE);
 
 	return (len > MAX_STRING_SIZE) ? 0 : len;
@@ -220,6 +226,9 @@ process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
 	case FETCH_OP_IMM:
 		val = code->immediate;
 		break;
+	case FETCH_OP_COMM:
+		val = FETCH_TOKEN_COMM;
+		break;
 	case FETCH_OP_FOFFS:
 		val = translate_user_vaddr(code->immediate);
 		break;
@@ -457,13 +466,19 @@ static int trace_uprobe_create(int argc, const char **argv)
 		return -ECANCELED;
 	}
 
+	trace_probe_log_init("trace_uprobe", argc, argv);
+	trace_probe_log_set_index(1);	/* filename is the 2nd argument */
+
 	*arg++ = '\0';
 	ret = kern_path(filename, LOOKUP_FOLLOW, &path);
 	if (ret) {
+		trace_probe_log_err(0, FILE_NOT_FOUND);
 		kfree(filename);
+		trace_probe_log_clear();
 		return ret;
 	}
 	if (!d_is_reg(path.dentry)) {
+		trace_probe_log_err(0, NO_REGULAR_FILE);
 		ret = -EINVAL;
 		goto fail_address_parse;
 	}
@@ -472,9 +487,16 @@ static int trace_uprobe_create(int argc, const char **argv)
 	rctr = strchr(arg, '(');
 	if (rctr) {
 		rctr_end = strchr(rctr, ')');
-		if (rctr > rctr_end || *(rctr_end + 1) != 0) {
+		if (!rctr_end) {
+			ret = -EINVAL;
+			rctr_end = rctr + strlen(rctr);
+			trace_probe_log_err(rctr_end - filename,
+					    REFCNT_OPEN_BRACE);
+			goto fail_address_parse;
+		} else if (rctr_end[1] != '\0') {
 			ret = -EINVAL;
-			pr_info("Invalid reference counter offset.\n");
+			trace_probe_log_err(rctr_end + 1 - filename,
+					    BAD_REFCNT_SUFFIX);
 			goto fail_address_parse;
 		}
 
@@ -482,22 +504,23 @@ static int trace_uprobe_create(int argc, const char **argv)
 		*rctr_end = '\0';
 		ret = kstrtoul(rctr, 0, &ref_ctr_offset);
 		if (ret) {
-			pr_info("Invalid reference counter offset.\n");
+			trace_probe_log_err(rctr - filename, BAD_REFCNT);
 			goto fail_address_parse;
 		}
 	}
 
 	/* Parse uprobe offset. */
 	ret = kstrtoul(arg, 0, &offset);
-	if (ret)
+	if (ret) {
+		trace_probe_log_err(arg - filename, BAD_UPROBE_OFFS);
 		goto fail_address_parse;
-
-	argc -= 2;
-	argv += 2;
+	}
 
 	/* setup a probe */
+	trace_probe_log_set_index(0);
 	if (event) {
-		ret = traceprobe_parse_event_name(&event, &group, buf);
+		ret = traceprobe_parse_event_name(&event, &group, buf,
+						  event - argv[0]);
 		if (ret)
 			goto fail_address_parse;
 	} else {
@@ -519,6 +542,9 @@ static int trace_uprobe_create(int argc, const char **argv)
 		kfree(tail);
 	}
 
+	argc -= 2;
+	argv += 2;
+
 	tu = alloc_trace_uprobe(group, event, argc, is_return);
 	if (IS_ERR(tu)) {
 		ret = PTR_ERR(tu);
@@ -539,6 +565,7 @@ static int trace_uprobe_create(int argc, const char **argv)
 			goto error;
 		}
 
+		trace_probe_log_set_index(i + 2);
 		ret = traceprobe_parse_probe_arg(&tu->tp, i, tmp,
 					is_return ? TPARG_FL_RETURN : 0);
 		kfree(tmp);
@@ -547,20 +574,20 @@ static int trace_uprobe_create(int argc, const char **argv)
 	}
 
 	ret = register_trace_uprobe(tu);
-	if (ret)
-		goto error;
-	return 0;
+	if (!ret)
+		goto out;
 
 error:
 	free_trace_uprobe(tu);
+out:
+	trace_probe_log_clear();
 	return ret;
 
 fail_address_parse:
+	trace_probe_log_clear();
 	path_put(&path);
 	kfree(filename);
 
-	pr_info("Failed to parse address or file.\n");
-
 	return ret;
 }
 

tools/testing/selftests/ftrace/test.d/ftrace/tracing-error-log.tc

+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: ftrace - test tracing error log support
+
+fail() { #msg
+    echo $1
+    exit_fail
+}
+
+# event tracing is currently the only ftrace tracer that uses the
+# tracing error_log, hence this check
+if [ ! -f set_event ]; then
+    echo "event tracing is not supported"
+    exit_unsupported
+fi
+
+ftrace_errlog_check 'event filter parse error' '((sig >= 10 && sig < 15) || dsig ^== 17) && comm != bash' 'events/signal/signal_generate/filter'
+
+exit 0

tools/testing/selftests/ftrace/test.d/functions

@@ -109,3 +109,15 @@ LOCALHOST=127.0.0.1
 yield() {
     ping $LOCALHOST -c 1 || sleep .001 || usleep 1 || sleep 1
 }
+
+ftrace_errlog_check() { # err-prefix command-with-error-pos-by-^ command-file
+    pos=$(echo -n "${2%^*}" | wc -c) # error position
+    command=$(echo "$2" | tr -d ^)
+    echo "Test command: $command"
+    echo > error_log
+    (! echo "$command" > "$3" ) 2> /dev/null
+    grep "$1: error:" -A 3 error_log
+    N=$(tail -n 1 error_log | wc -c)
+    # "  Command: " and "^\n" => 13
+    test $(expr 13 + $pos) -eq $N
+}

tools/testing/selftests/ftrace/test.d/kprobe/kprobe_syntax_errors.tc

+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Kprobe event parser error log check
+
+[ -f kprobe_events ] || exit_unsupported # this is configurable
+
+[ -f error_log ] || exit_unsupported
+
+check_error() { # command-with-error-pos-by-^
+    ftrace_errlog_check 'trace_kprobe' "$1" 'kprobe_events'
+}
+
+if grep -q 'r\[maxactive\]' README; then
+check_error 'p^100 vfs_read'		# MAXACT_NO_KPROBE
+check_error 'r^1a111 vfs_read'		# BAD_MAXACT
+check_error 'r^100000 vfs_read'		# MAXACT_TOO_BIG
+fi
+
+check_error 'p ^non_exist_func'		# BAD_PROBE_ADDR (enoent)
+check_error 'p ^hoge-fuga'		# BAD_PROBE_ADDR (bad syntax)
+check_error 'p ^hoge+1000-1000'		# BAD_PROBE_ADDR (bad syntax)
+check_error 'r ^vfs_read+10'		# BAD_RETPROBE
+check_error 'p:^/bar vfs_read'		# NO_GROUP_NAME
+check_error 'p:^12345678901234567890123456789012345678901234567890123456789012345/bar vfs_read'	# GROUP_TOO_LONG
+
+check_error 'p:^foo.1/bar vfs_read'	# BAD_GROUP_NAME
+check_error 'p:foo/^ vfs_read'		# NO_EVENT_NAME
+check_error 'p:foo/^12345678901234567890123456789012345678901234567890123456789012345 vfs_read'	# EVENT_TOO_LONG
+check_error 'p:foo/^bar.1 vfs_read'	# BAD_EVENT_NAME
+
+check_error 'p vfs_read ^$retval'	# RETVAL_ON_PROBE
+check_error 'p vfs_read ^$stack10000'	# BAD_STACK_NUM
+
+if grep -q '$arg<N>' README; then
+check_error 'p vfs_read ^$arg10000'	# BAD_ARG_NUM
+fi
+
+check_error 'p vfs_read ^$none_var'	# BAD_VAR
+
+check_error 'p vfs_read ^%none_reg'	# BAD_REG_NAME
+check_error 'p vfs_read ^@12345678abcde'	# BAD_MEM_ADDR
+check_error 'p vfs_read ^@+10'		# FILE_ON_KPROBE
+
+check_error 'p vfs_read ^+0@0)'		# DEREF_NEED_BRACE
+check_error 'p vfs_read ^+0ab1(@0)'	# BAD_DEREF_OFFS
+check_error 'p vfs_read +0(+0(@0^)'	# DEREF_OPEN_BRACE
+
+if grep -A1 "fetcharg:" README | grep -q '\$comm' ; then
+check_error 'p vfs_read +0(^$comm)'	# COMM_CANT_DEREF
+fi
+
+check_error 'p vfs_read ^&1'		# BAD_FETCH_ARG
+
+
+# We've introduced this limitation with array support
+if grep -q ' <type>\\\[<array-size>\\\]' README; then
+check_error 'p vfs_read +0(^+0(+0(+0(+0(+0(+0(+0(+0(+0(+0(+0(+0(+0(@0))))))))))))))'	# TOO_MANY_OPS?
+check_error 'p vfs_read +0(@11):u8[10^'		# ARRAY_NO_CLOSE
+check_error 'p vfs_read +0(@11):u8[10]^a'	# BAD_ARRAY_SUFFIX
+check_error 'p vfs_read +0(@11):u8[^10a]'	# BAD_ARRAY_NUM
+check_error 'p vfs_read +0(@11):u8[^256]'	# ARRAY_TOO_BIG
+fi
+
+check_error 'p vfs_read @11:^unknown_type'	# BAD_TYPE
+check_error 'p vfs_read $stack0:^string'	# BAD_STRING
+check_error 'p vfs_read @11:^b10@a/16'		# BAD_BITFIELD
+
+check_error 'p vfs_read ^arg123456789012345678901234567890=@11'	# ARG_NAME_TOO_LOG
+check_error 'p vfs_read ^=@11'			# NO_ARG_NAME
+check_error 'p vfs_read ^var.1=@11'		# BAD_ARG_NAME
+check_error 'p vfs_read var1=@11 ^var1=@12'	# USED_ARG_NAME
+check_error 'p vfs_read ^+1234567(+1234567(+1234567(+1234567(+1234567(+1234567(@1234))))))'	# ARG_TOO_LONG
+check_error 'p vfs_read arg1=^'			# NO_ARG_BODY
+
+# instruction boundary check is valid on x86 (at this moment)
+case $(uname -m) in
+  x86_64|i[3456]86)
+    echo 'p vfs_read' > kprobe_events
+    if grep -q FTRACE ../kprobes/list ; then
+	check_error 'p ^vfs_read+3'		# BAD_INSN_BNDRY (only if function-tracer is enabled)
+    fi
+    ;;
+esac
+
+exit 0

tools/testing/selftests/ftrace/test.d/kprobe/uprobe_syntax_errors.tc

+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Uprobe event parser error log check
+
+[ -f uprobe_events ] || exit_unsupported # this is configurable
+
+[ -f error_log ] || exit_unsupported
+
+check_error() { # command-with-error-pos-by-^
+    ftrace_errlog_check 'trace_uprobe' "$1" 'uprobe_events'
+}
+
+check_error 'p ^/non_exist_file:100'	# FILE_NOT_FOUND
+check_error 'p ^/sys:100'		# NO_REGULAR_FILE
+check_error 'p /bin/sh:^10a'		# BAD_UPROBE_OFFS
+check_error 'p /bin/sh:10(^1a)'		# BAD_REFCNT
+check_error 'p /bin/sh:10(10^'		# REFCNT_OPEN_BRACE
+check_error 'p /bin/sh:10(10)^a'	# BAD_REFCNT_SUFFIX
+
+check_error 'p /bin/sh:10 ^@+ab'	# BAD_FILE_OFFS
+check_error 'p /bin/sh:10 ^@symbol'	# SYM_ON_UPROBE
+
+exit 0

tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-extended-error-support.tc

-#!/bin/sh
-# SPDX-License-Identifier: GPL-2.0
-# description: event trigger - test extended error support
-
-
-fail() { #msg
-    echo $1
-    exit_fail
-}
-
-if [ ! -f set_event ]; then
-    echo "event tracing is not supported"
-    exit_unsupported
-fi
-
-if [ ! -f synthetic_events ]; then
-    echo "synthetic event is not supported"
-    exit_unsupported
-fi
-
-echo "Test extended error support"
-echo 'hist:keys=pid:ts0=common_timestamp.usecs if comm=="ping"' > events/sched/sched_wakeup/trigger
-! echo 'hist:keys=pid:ts0=common_timestamp.usecs if comm=="ping"' >> events/sched/sched_wakeup/trigger 2> /dev/null
-if ! grep -q "ERROR:" events/sched/sched_wakeup/hist; then
-    fail "Failed to generate extended error in histogram"
-fi
-
-exit 0