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Date: Tue, 12 Jan 2016 14:10:50 -0500
From: Steven Rostedt <rostedt@...dmis.org>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: LKML <linux-kernel@...r.kernel.org>,
Ingo Molnar <mingo@...nel.org>,
Andrew Morton <akpm@...ux-foundation.org>
Subject: [GIT PULL] tracing: Updates for 4.5
Linus,
Not much new with tracing for this release. Mostly just clean ups and
minor fixes.
Here's what else is new:
o A new TRACE_EVENT_FN_COND macro, combining both _FN and _COND for
those that want both.
o New selftest to test the instance create and delete
o Better debug output when ftrace fails
Please pull the latest trace-v4.5 tree, which can be found at:
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
trace-v4.5
Tag SHA1: ed21d378b25dc8650479d7b4683d1eb680beb712
Head SHA1: 5156dca34a3e1e1edac2d0dabf43d8632909b7aa
Abel Vesa (1):
ftrace: Join functions ftrace_module_init() and ftrace_init_module()
Chuyu Hu (1):
tracing: Fix comment to use tracing_on over tracing_enable
Denis Kirjanov (1):
tracing: Introduce TRACE_EVENT_FN_COND macro
Jerry Snitselaar (1):
tracing: Use seq_buf_used() in seq_buf_to_user() instead of len
Julia Lawall (1):
bpf: Constify bpf_verifier_ops structure
Li Bin (5):
ftrace: Fix a typo in comment
ia64: ftrace: Fix the comments for ftrace_modify_code()
sh: ftrace: Fix the comments for ftrace_modify_code()
metag: ftrace: Fix the comments for ftrace_modify_code
x86: ftrace: Fix the comments for ftrace_modify_code_direct()
Qiu Peiyang (1):
ftrace: Fix the race between ftrace and insmod
Steven Rostedt (Red Hat) (14):
ring-buffer: Update read stamp with first real commit on page
ring-buffer: Put back the length if crossed page with add_timestamp
ftracetest: Add instance create and delete test
ring-buffer: Use READ_ONCE() for most tail_page access
ring-buffer: Remove redundant update of page timestamp
ring-buffer: Process commits whenever moving to a new page.
ftrace: Add new type to distinguish what kind of ftrace_bug()
ftrace: Add variable ftrace_expected for archs to show expected code
ftrace: Show all tramps registered to a record on ftrace_bug()
ftrace: Fix output of enabled_functions for showing tramp
ftrace: Remove use of control list and ops
ftrace: Have ftrace_ops_get_func() handle RCU and PER_CPU flags too
ftrace: Clean up ftrace_module_init() code
ftrace: Add infrastructure for delayed enabling of module functions
Tom Zanussi (1):
tracing: Update cond flag when enabling or disabling a trigger
----
arch/ia64/kernel/ftrace.c | 12 +-
arch/metag/kernel/ftrace.c | 11 +-
arch/sh/kernel/ftrace.c | 12 +-
arch/x86/kernel/ftrace.c | 21 +-
include/linux/ftrace.h | 56 ++-
include/linux/tracepoint.h | 4 +
include/trace/define_trace.h | 6 +
include/trace/trace_events.h | 6 +
kernel/trace/bpf_trace.c | 2 +-
kernel/trace/ftrace.c | 451 ++++++++++++---------
kernel/trace/ring_buffer.c | 74 ++--
kernel/trace/trace.h | 6 +-
kernel/trace/trace_event_perf.c | 2 +-
kernel/trace/trace_events_trigger.c | 10 +-
lib/seq_buf.c | 6 +-
.../selftests/ftrace/test.d/instances/instance.tc | 90 ++++
16 files changed, 485 insertions(+), 284 deletions(-)
create mode 100644 tools/testing/selftests/ftrace/test.d/instances/instance.tc
---------------------------
diff --git a/arch/ia64/kernel/ftrace.c b/arch/ia64/kernel/ftrace.c
index 3b0c2aa07857..cee411e647ca 100644
--- a/arch/ia64/kernel/ftrace.c
+++ b/arch/ia64/kernel/ftrace.c
@@ -97,13 +97,11 @@ ftrace_modify_code(unsigned long ip, unsigned char *old_code,
unsigned char replaced[MCOUNT_INSN_SIZE];
/*
- * Note: Due to modules and __init, code can
- * disappear and change, we need to protect against faulting
- * as well as code changing. We do this by using the
- * probe_kernel_* functions.
- *
- * No real locking needed, this code is run through
- * kstop_machine, or before SMP starts.
+ * Note:
+ * We are paranoid about modifying text, as if a bug was to happen, it
+ * could cause us to read or write to someplace that could cause harm.
+ * Carefully read and modify the code with probe_kernel_*(), and make
+ * sure what we read is what we expected it to be before modifying it.
*/
if (!do_check)
diff --git a/arch/metag/kernel/ftrace.c b/arch/metag/kernel/ftrace.c
index ed1d685157c2..ac8c039b0318 100644
--- a/arch/metag/kernel/ftrace.c
+++ b/arch/metag/kernel/ftrace.c
@@ -54,12 +54,11 @@ static int ftrace_modify_code(unsigned long pc, unsigned char *old_code,
unsigned char replaced[MCOUNT_INSN_SIZE];
/*
- * Note: Due to modules and __init, code can
- * disappear and change, we need to protect against faulting
- * as well as code changing.
- *
- * No real locking needed, this code is run through
- * kstop_machine.
+ * Note:
+ * We are paranoid about modifying text, as if a bug was to happen, it
+ * could cause us to read or write to someplace that could cause harm.
+ * Carefully read and modify the code with probe_kernel_*(), and make
+ * sure what we read is what we expected it to be before modifying it.
*/
/* read the text we want to modify */
diff --git a/arch/sh/kernel/ftrace.c b/arch/sh/kernel/ftrace.c
index 079d70e6d74b..38993e09ef03 100644
--- a/arch/sh/kernel/ftrace.c
+++ b/arch/sh/kernel/ftrace.c
@@ -212,13 +212,11 @@ static int ftrace_modify_code(unsigned long ip, unsigned char *old_code,
unsigned char replaced[MCOUNT_INSN_SIZE];
/*
- * Note: Due to modules and __init, code can
- * disappear and change, we need to protect against faulting
- * as well as code changing. We do this by using the
- * probe_kernel_* functions.
- *
- * No real locking needed, this code is run through
- * kstop_machine, or before SMP starts.
+ * Note:
+ * We are paranoid about modifying text, as if a bug was to happen, it
+ * could cause us to read or write to someplace that could cause harm.
+ * Carefully read and modify the code with probe_kernel_*(), and make
+ * sure what we read is what we expected it to be before modifying it.
*/
/* read the text we want to modify */
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 311bcf338f07..29408d6d6626 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -105,14 +105,14 @@ ftrace_modify_code_direct(unsigned long ip, unsigned const char *old_code,
{
unsigned char replaced[MCOUNT_INSN_SIZE];
+ ftrace_expected = old_code;
+
/*
- * Note: Due to modules and __init, code can
- * disappear and change, we need to protect against faulting
- * as well as code changing. We do this by using the
- * probe_kernel_* functions.
- *
- * No real locking needed, this code is run through
- * kstop_machine, or before SMP starts.
+ * Note:
+ * We are paranoid about modifying text, as if a bug was to happen, it
+ * could cause us to read or write to someplace that could cause harm.
+ * Carefully read and modify the code with probe_kernel_*(), and make
+ * sure what we read is what we expected it to be before modifying it.
*/
/* read the text we want to modify */
@@ -154,6 +154,8 @@ int ftrace_make_nop(struct module *mod,
if (addr == MCOUNT_ADDR)
return ftrace_modify_code_direct(rec->ip, old, new);
+ ftrace_expected = NULL;
+
/* Normal cases use add_brk_on_nop */
WARN_ONCE(1, "invalid use of ftrace_make_nop");
return -EINVAL;
@@ -220,6 +222,7 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
unsigned long addr)
{
WARN_ON(1);
+ ftrace_expected = NULL;
return -EINVAL;
}
@@ -314,6 +317,8 @@ static int add_break(unsigned long ip, const char *old)
if (probe_kernel_read(replaced, (void *)ip, MCOUNT_INSN_SIZE))
return -EFAULT;
+ ftrace_expected = old;
+
/* Make sure it is what we expect it to be */
if (memcmp(replaced, old, MCOUNT_INSN_SIZE) != 0)
return -EINVAL;
@@ -413,6 +418,8 @@ static int remove_breakpoint(struct dyn_ftrace *rec)
ftrace_addr = ftrace_get_addr_curr(rec);
nop = ftrace_call_replace(ip, ftrace_addr);
+ ftrace_expected = nop;
+
if (memcmp(&ins[1], &nop[1], MCOUNT_INSN_SIZE - 1) != 0)
return -EINVAL;
}
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index eae6548efbf0..660e7c698f3b 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -76,8 +76,8 @@ ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops);
* ENABLED - set/unset when ftrace_ops is registered/unregistered
* DYNAMIC - set when ftrace_ops is registered to denote dynamically
* allocated ftrace_ops which need special care
- * CONTROL - set manualy by ftrace_ops user to denote the ftrace_ops
- * could be controled by following calls:
+ * PER_CPU - set manualy by ftrace_ops user to denote the ftrace_ops
+ * could be controlled by following calls:
* ftrace_function_local_enable
* ftrace_function_local_disable
* SAVE_REGS - The ftrace_ops wants regs saved at each function called
@@ -121,7 +121,7 @@ ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops);
enum {
FTRACE_OPS_FL_ENABLED = 1 << 0,
FTRACE_OPS_FL_DYNAMIC = 1 << 1,
- FTRACE_OPS_FL_CONTROL = 1 << 2,
+ FTRACE_OPS_FL_PER_CPU = 1 << 2,
FTRACE_OPS_FL_SAVE_REGS = 1 << 3,
FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED = 1 << 4,
FTRACE_OPS_FL_RECURSION_SAFE = 1 << 5,
@@ -134,6 +134,7 @@ enum {
FTRACE_OPS_FL_ALLOC_TRAMP = 1 << 12,
FTRACE_OPS_FL_IPMODIFY = 1 << 13,
FTRACE_OPS_FL_PID = 1 << 14,
+ FTRACE_OPS_FL_RCU = 1 << 15,
};
#ifdef CONFIG_DYNAMIC_FTRACE
@@ -146,11 +147,11 @@ struct ftrace_ops_hash {
#endif
/*
- * Note, ftrace_ops can be referenced outside of RCU protection.
- * (Although, for perf, the control ops prevent that). If ftrace_ops is
- * allocated and not part of kernel core data, the unregistering of it will
- * perform a scheduling on all CPUs to make sure that there are no more users.
- * Depending on the load of the system that may take a bit of time.
+ * Note, ftrace_ops can be referenced outside of RCU protection, unless
+ * the RCU flag is set. If ftrace_ops is allocated and not part of kernel
+ * core data, the unregistering of it will perform a scheduling on all CPUs
+ * to make sure that there are no more users. Depending on the load of the
+ * system that may take a bit of time.
*
* Any private data added must also take care not to be freed and if private
* data is added to a ftrace_ops that is in core code, the user of the
@@ -196,34 +197,34 @@ int unregister_ftrace_function(struct ftrace_ops *ops);
void clear_ftrace_function(void);
/**
- * ftrace_function_local_enable - enable controlled ftrace_ops on current cpu
+ * ftrace_function_local_enable - enable ftrace_ops on current cpu
*
* This function enables tracing on current cpu by decreasing
* the per cpu control variable.
* It must be called with preemption disabled and only on ftrace_ops
- * registered with FTRACE_OPS_FL_CONTROL. If called without preemption
+ * registered with FTRACE_OPS_FL_PER_CPU. If called without preemption
* disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.
*/
static inline void ftrace_function_local_enable(struct ftrace_ops *ops)
{
- if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_CONTROL)))
+ if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU)))
return;
(*this_cpu_ptr(ops->disabled))--;
}
/**
- * ftrace_function_local_disable - enable controlled ftrace_ops on current cpu
+ * ftrace_function_local_disable - disable ftrace_ops on current cpu
*
- * This function enables tracing on current cpu by decreasing
+ * This function disables tracing on current cpu by increasing
* the per cpu control variable.
* It must be called with preemption disabled and only on ftrace_ops
- * registered with FTRACE_OPS_FL_CONTROL. If called without preemption
+ * registered with FTRACE_OPS_FL_PER_CPU. If called without preemption
* disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.
*/
static inline void ftrace_function_local_disable(struct ftrace_ops *ops)
{
- if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_CONTROL)))
+ if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU)))
return;
(*this_cpu_ptr(ops->disabled))++;
@@ -235,12 +236,12 @@ static inline void ftrace_function_local_disable(struct ftrace_ops *ops)
*
* This function returns value of ftrace_ops::disabled on current cpu.
* It must be called with preemption disabled and only on ftrace_ops
- * registered with FTRACE_OPS_FL_CONTROL. If called without preemption
+ * registered with FTRACE_OPS_FL_PER_CPU. If called without preemption
* disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.
*/
static inline int ftrace_function_local_disabled(struct ftrace_ops *ops)
{
- WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_CONTROL));
+ WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU));
return *this_cpu_ptr(ops->disabled);
}
@@ -296,6 +297,21 @@ int ftrace_arch_code_modify_post_process(void);
struct dyn_ftrace;
+enum ftrace_bug_type {
+ FTRACE_BUG_UNKNOWN,
+ FTRACE_BUG_INIT,
+ FTRACE_BUG_NOP,
+ FTRACE_BUG_CALL,
+ FTRACE_BUG_UPDATE,
+};
+extern enum ftrace_bug_type ftrace_bug_type;
+
+/*
+ * Archs can set this to point to a variable that holds the value that was
+ * expected at the call site before calling ftrace_bug().
+ */
+extern const void *ftrace_expected;
+
void ftrace_bug(int err, struct dyn_ftrace *rec);
struct seq_file;
@@ -341,6 +357,7 @@ bool is_ftrace_trampoline(unsigned long addr);
* REGS - the record wants the function to save regs
* REGS_EN - the function is set up to save regs.
* IPMODIFY - the record allows for the IP address to be changed.
+ * DISABLED - the record is not ready to be touched yet
*
* When a new ftrace_ops is registered and wants a function to save
* pt_regs, the rec->flag REGS is set. When the function has been
@@ -355,10 +372,11 @@ enum {
FTRACE_FL_TRAMP = (1UL << 28),
FTRACE_FL_TRAMP_EN = (1UL << 27),
FTRACE_FL_IPMODIFY = (1UL << 26),
+ FTRACE_FL_DISABLED = (1UL << 25),
};
-#define FTRACE_REF_MAX_SHIFT 26
-#define FTRACE_FL_BITS 6
+#define FTRACE_REF_MAX_SHIFT 25
+#define FTRACE_FL_BITS 7
#define FTRACE_FL_MASKED_BITS ((1UL << FTRACE_FL_BITS) - 1)
#define FTRACE_FL_MASK (FTRACE_FL_MASKED_BITS << FTRACE_REF_MAX_SHIFT)
#define FTRACE_REF_MAX ((1UL << FTRACE_REF_MAX_SHIFT) - 1)
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index 696a339c592c..45b3fcf7dd3c 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -493,6 +493,10 @@ extern void syscall_unregfunc(void);
#define TRACE_EVENT_FN(name, proto, args, struct, \
assign, print, reg, unreg) \
DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
+#define TRACE_EVENT_FN_COND(name, proto, args, cond, struct, \
+ assign, print, reg, unreg) \
+ DECLARE_TRACE_CONDITION(name, PARAMS(proto), \
+ PARAMS(args), PARAMS(cond))
#define TRACE_EVENT_CONDITION(name, proto, args, cond, \
struct, assign, print) \
DECLARE_TRACE_CONDITION(name, PARAMS(proto), \
diff --git a/include/trace/define_trace.h b/include/trace/define_trace.h
index 2d8639ea64d5..6e3945f64102 100644
--- a/include/trace/define_trace.h
+++ b/include/trace/define_trace.h
@@ -40,6 +40,11 @@
assign, print, reg, unreg) \
DEFINE_TRACE_FN(name, reg, unreg)
+#undef TRACE_EVENT_FN_COND
+#define TRACE_EVENT_FN_COND(name, proto, args, cond, tstruct, \
+ assign, print, reg, unreg) \
+ DEFINE_TRACE_FN(name, reg, unreg)
+
#undef DEFINE_EVENT
#define DEFINE_EVENT(template, name, proto, args) \
DEFINE_TRACE(name)
@@ -93,6 +98,7 @@
#undef TRACE_EVENT
#undef TRACE_EVENT_FN
+#undef TRACE_EVENT_FN_COND
#undef TRACE_EVENT_CONDITION
#undef DECLARE_EVENT_CLASS
#undef DEFINE_EVENT
diff --git a/include/trace/trace_events.h b/include/trace/trace_events.h
index de996cf61053..170c93bbdbb7 100644
--- a/include/trace/trace_events.h
+++ b/include/trace/trace_events.h
@@ -123,6 +123,12 @@ TRACE_MAKE_SYSTEM_STR();
TRACE_EVENT(name, PARAMS(proto), PARAMS(args), \
PARAMS(tstruct), PARAMS(assign), PARAMS(print)) \
+#undef TRACE_EVENT_FN_COND
+#define TRACE_EVENT_FN_COND(name, proto, args, cond, tstruct, \
+ assign, print, reg, unreg) \
+ TRACE_EVENT_CONDITION(name, PARAMS(proto), PARAMS(args), PARAMS(cond), \
+ PARAMS(tstruct), PARAMS(assign), PARAMS(print)) \
+
#undef TRACE_EVENT_FLAGS
#define TRACE_EVENT_FLAGS(name, value) \
__TRACE_EVENT_FLAGS(name, value)
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 4228fd3682c3..45dd798bcd37 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -316,7 +316,7 @@ static bool kprobe_prog_is_valid_access(int off, int size, enum bpf_access_type
return true;
}
-static struct bpf_verifier_ops kprobe_prog_ops = {
+static const struct bpf_verifier_ops kprobe_prog_ops = {
.get_func_proto = kprobe_prog_func_proto,
.is_valid_access = kprobe_prog_is_valid_access,
};
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 3f743b147247..eca592f977b2 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -62,8 +62,6 @@
#define FTRACE_HASH_DEFAULT_BITS 10
#define FTRACE_HASH_MAX_BITS 12
-#define FL_GLOBAL_CONTROL_MASK (FTRACE_OPS_FL_CONTROL)
-
#ifdef CONFIG_DYNAMIC_FTRACE
#define INIT_OPS_HASH(opsname) \
.func_hash = &opsname.local_hash, \
@@ -113,14 +111,9 @@ static int ftrace_disabled __read_mostly;
static DEFINE_MUTEX(ftrace_lock);
-static struct ftrace_ops *ftrace_control_list __read_mostly = &ftrace_list_end;
static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
static struct ftrace_ops global_ops;
-static struct ftrace_ops control_ops;
-
-static void ftrace_ops_recurs_func(unsigned long ip, unsigned long parent_ip,
- struct ftrace_ops *op, struct pt_regs *regs);
#if ARCH_SUPPORTS_FTRACE_OPS
static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
@@ -203,7 +196,7 @@ void clear_ftrace_function(void)
ftrace_trace_function = ftrace_stub;
}
-static void control_ops_disable_all(struct ftrace_ops *ops)
+static void per_cpu_ops_disable_all(struct ftrace_ops *ops)
{
int cpu;
@@ -211,16 +204,19 @@ static void control_ops_disable_all(struct ftrace_ops *ops)
*per_cpu_ptr(ops->disabled, cpu) = 1;
}
-static int control_ops_alloc(struct ftrace_ops *ops)
+static int per_cpu_ops_alloc(struct ftrace_ops *ops)
{
int __percpu *disabled;
+ if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU)))
+ return -EINVAL;
+
disabled = alloc_percpu(int);
if (!disabled)
return -ENOMEM;
ops->disabled = disabled;
- control_ops_disable_all(ops);
+ per_cpu_ops_disable_all(ops);
return 0;
}
@@ -256,10 +252,11 @@ static inline void update_function_graph_func(void) { }
static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
{
/*
- * If this is a dynamic ops or we force list func,
+ * If this is a dynamic, RCU, or per CPU ops, or we force list func,
* then it needs to call the list anyway.
*/
- if (ops->flags & FTRACE_OPS_FL_DYNAMIC || FTRACE_FORCE_LIST_FUNC)
+ if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU |
+ FTRACE_OPS_FL_RCU) || FTRACE_FORCE_LIST_FUNC)
return ftrace_ops_list_func;
return ftrace_ops_get_func(ops);
@@ -383,26 +380,6 @@ static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
return 0;
}
-static void add_ftrace_list_ops(struct ftrace_ops **list,
- struct ftrace_ops *main_ops,
- struct ftrace_ops *ops)
-{
- int first = *list == &ftrace_list_end;
- add_ftrace_ops(list, ops);
- if (first)
- add_ftrace_ops(&ftrace_ops_list, main_ops);
-}
-
-static int remove_ftrace_list_ops(struct ftrace_ops **list,
- struct ftrace_ops *main_ops,
- struct ftrace_ops *ops)
-{
- int ret = remove_ftrace_ops(list, ops);
- if (!ret && *list == &ftrace_list_end)
- ret = remove_ftrace_ops(&ftrace_ops_list, main_ops);
- return ret;
-}
-
static void ftrace_update_trampoline(struct ftrace_ops *ops);
static int __register_ftrace_function(struct ftrace_ops *ops)
@@ -430,14 +407,12 @@ static int __register_ftrace_function(struct ftrace_ops *ops)
if (!core_kernel_data((unsigned long)ops))
ops->flags |= FTRACE_OPS_FL_DYNAMIC;
- if (ops->flags & FTRACE_OPS_FL_CONTROL) {
- if (control_ops_alloc(ops))
+ if (ops->flags & FTRACE_OPS_FL_PER_CPU) {
+ if (per_cpu_ops_alloc(ops))
return -ENOMEM;
- add_ftrace_list_ops(&ftrace_control_list, &control_ops, ops);
- /* The control_ops needs the trampoline update */
- ops = &control_ops;
- } else
- add_ftrace_ops(&ftrace_ops_list, ops);
+ }
+
+ add_ftrace_ops(&ftrace_ops_list, ops);
/* Always save the function, and reset at unregistering */
ops->saved_func = ops->func;
@@ -460,11 +435,7 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops)
if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
return -EBUSY;
- if (ops->flags & FTRACE_OPS_FL_CONTROL) {
- ret = remove_ftrace_list_ops(&ftrace_control_list,
- &control_ops, ops);
- } else
- ret = remove_ftrace_ops(&ftrace_ops_list, ops);
+ ret = remove_ftrace_ops(&ftrace_ops_list, ops);
if (ret < 0)
return ret;
@@ -1687,6 +1658,9 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
int in_hash = 0;
int match = 0;
+ if (rec->flags & FTRACE_FL_DISABLED)
+ continue;
+
if (all) {
/*
* Only the filter_hash affects all records.
@@ -1940,7 +1914,7 @@ static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
}
-static void print_ip_ins(const char *fmt, unsigned char *p)
+static void print_ip_ins(const char *fmt, const unsigned char *p)
{
int i;
@@ -1952,6 +1926,31 @@ static void print_ip_ins(const char *fmt, unsigned char *p)
static struct ftrace_ops *
ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
+static struct ftrace_ops *
+ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
+
+enum ftrace_bug_type ftrace_bug_type;
+const void *ftrace_expected;
+
+static void print_bug_type(void)
+{
+ switch (ftrace_bug_type) {
+ case FTRACE_BUG_UNKNOWN:
+ break;
+ case FTRACE_BUG_INIT:
+ pr_info("Initializing ftrace call sites\n");
+ break;
+ case FTRACE_BUG_NOP:
+ pr_info("Setting ftrace call site to NOP\n");
+ break;
+ case FTRACE_BUG_CALL:
+ pr_info("Setting ftrace call site to call ftrace function\n");
+ break;
+ case FTRACE_BUG_UPDATE:
+ pr_info("Updating ftrace call site to call a different ftrace function\n");
+ break;
+ }
+}
/**
* ftrace_bug - report and shutdown function tracer
@@ -1979,8 +1978,12 @@ void ftrace_bug(int failed, struct dyn_ftrace *rec)
FTRACE_WARN_ON_ONCE(1);
pr_info("ftrace failed to modify ");
print_ip_sym(ip);
- print_ip_ins(" actual: ", (unsigned char *)ip);
+ print_ip_ins(" actual: ", (unsigned char *)ip);
pr_cont("\n");
+ if (ftrace_expected) {
+ print_ip_ins(" expected: ", ftrace_expected);
+ pr_cont("\n");
+ }
break;
case -EPERM:
FTRACE_WARN_ON_ONCE(1);
@@ -1992,6 +1995,7 @@ void ftrace_bug(int failed, struct dyn_ftrace *rec)
pr_info("ftrace faulted on unknown error ");
print_ip_sym(ip);
}
+ print_bug_type();
if (rec) {
struct ftrace_ops *ops = NULL;
@@ -2000,15 +2004,19 @@ void ftrace_bug(int failed, struct dyn_ftrace *rec)
rec->flags & FTRACE_FL_REGS ? " R" : " ");
if (rec->flags & FTRACE_FL_TRAMP_EN) {
ops = ftrace_find_tramp_ops_any(rec);
- if (ops)
- pr_cont("\ttramp: %pS",
- (void *)ops->trampoline);
- else
+ if (ops) {
+ do {
+ pr_cont("\ttramp: %pS (%pS)",
+ (void *)ops->trampoline,
+ (void *)ops->func);
+ ops = ftrace_find_tramp_ops_next(rec, ops);
+ } while (ops);
+ } else
pr_cont("\ttramp: ERROR!");
}
ip = ftrace_get_addr_curr(rec);
- pr_cont(" expected tramp: %lx\n", ip);
+ pr_cont("\n expected tramp: %lx\n", ip);
}
}
@@ -2016,6 +2024,11 @@ static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
{
unsigned long flag = 0UL;
+ ftrace_bug_type = FTRACE_BUG_UNKNOWN;
+
+ if (rec->flags & FTRACE_FL_DISABLED)
+ return FTRACE_UPDATE_IGNORE;
+
/*
* If we are updating calls:
*
@@ -2077,9 +2090,12 @@ static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
* from the save regs, to a non-save regs function or
* vice versa, or from a trampoline call.
*/
- if (flag & FTRACE_FL_ENABLED)
+ if (flag & FTRACE_FL_ENABLED) {
+ ftrace_bug_type = FTRACE_BUG_CALL;
return FTRACE_UPDATE_MAKE_CALL;
+ }
+ ftrace_bug_type = FTRACE_BUG_UPDATE;
return FTRACE_UPDATE_MODIFY_CALL;
}
@@ -2096,6 +2112,7 @@ static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
FTRACE_FL_REGS_EN);
}
+ ftrace_bug_type = FTRACE_BUG_NOP;
return FTRACE_UPDATE_MAKE_NOP;
}
@@ -2145,6 +2162,24 @@ ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
}
static struct ftrace_ops *
+ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
+ struct ftrace_ops *op)
+{
+ unsigned long ip = rec->ip;
+
+ while_for_each_ftrace_op(op) {
+
+ if (!op->trampoline)
+ continue;
+
+ if (hash_contains_ip(ip, op->func_hash))
+ return op;
+ }
+
+ return NULL;
+}
+
+static struct ftrace_ops *
ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
{
struct ftrace_ops *op;
@@ -2307,17 +2342,22 @@ __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
ret = ftrace_update_record(rec, enable);
+ ftrace_bug_type = FTRACE_BUG_UNKNOWN;
+
switch (ret) {
case FTRACE_UPDATE_IGNORE:
return 0;
case FTRACE_UPDATE_MAKE_CALL:
+ ftrace_bug_type = FTRACE_BUG_CALL;
return ftrace_make_call(rec, ftrace_addr);
case FTRACE_UPDATE_MAKE_NOP:
+ ftrace_bug_type = FTRACE_BUG_NOP;
return ftrace_make_nop(NULL, rec, ftrace_old_addr);
case FTRACE_UPDATE_MODIFY_CALL:
+ ftrace_bug_type = FTRACE_BUG_UPDATE;
return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
}
@@ -2425,6 +2465,7 @@ ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
if (ret) {
+ ftrace_bug_type = FTRACE_BUG_INIT;
ftrace_bug(ret, rec);
return 0;
}
@@ -2566,7 +2607,7 @@ void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
{
}
-static void control_ops_free(struct ftrace_ops *ops)
+static void per_cpu_ops_free(struct ftrace_ops *ops)
{
free_percpu(ops->disabled);
}
@@ -2667,13 +2708,13 @@ static int ftrace_shutdown(struct ftrace_ops *ops, int command)
if (!command || !ftrace_enabled) {
/*
- * If these are control ops, they still need their
+ * If these are per_cpu ops, they still need their
* per_cpu field freed. Since, function tracing is
* not currently active, we can just free them
* without synchronizing all CPUs.
*/
- if (ops->flags & FTRACE_OPS_FL_CONTROL)
- control_ops_free(ops);
+ if (ops->flags & FTRACE_OPS_FL_PER_CPU)
+ per_cpu_ops_free(ops);
return 0;
}
@@ -2714,7 +2755,7 @@ static int ftrace_shutdown(struct ftrace_ops *ops, int command)
/*
* Dynamic ops may be freed, we must make sure that all
* callers are done before leaving this function.
- * The same goes for freeing the per_cpu data of the control
+ * The same goes for freeing the per_cpu data of the per_cpu
* ops.
*
* Again, normal synchronize_sched() is not good enough.
@@ -2725,13 +2766,13 @@ static int ftrace_shutdown(struct ftrace_ops *ops, int command)
* infrastructure to do the synchronization, thus we must do it
* ourselves.
*/
- if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_CONTROL)) {
+ if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU)) {
schedule_on_each_cpu(ftrace_sync);
arch_ftrace_trampoline_free(ops);
- if (ops->flags & FTRACE_OPS_FL_CONTROL)
- control_ops_free(ops);
+ if (ops->flags & FTRACE_OPS_FL_PER_CPU)
+ per_cpu_ops_free(ops);
}
return 0;
@@ -2798,9 +2839,9 @@ ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
return 0;
- /* If ops traces all mods, we already accounted for it */
+ /* If ops traces all then it includes this function */
if (ops_traces_mod(ops))
- return 0;
+ return 1;
/* The function must be in the filter */
if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
@@ -2814,64 +2855,41 @@ ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
return 1;
}
-static int referenced_filters(struct dyn_ftrace *rec)
-{
- struct ftrace_ops *ops;
- int cnt = 0;
-
- for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
- if (ops_references_rec(ops, rec))
- cnt++;
- }
-
- return cnt;
-}
-
static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
{
struct ftrace_page *pg;
struct dyn_ftrace *p;
cycle_t start, stop;
unsigned long update_cnt = 0;
- unsigned long ref = 0;
- bool test = false;
+ unsigned long rec_flags = 0;
int i;
+ start = ftrace_now(raw_smp_processor_id());
+
/*
- * When adding a module, we need to check if tracers are
- * currently enabled and if they are set to trace all functions.
- * If they are, we need to enable the module functions as well
- * as update the reference counts for those function records.
+ * When a module is loaded, this function is called to convert
+ * the calls to mcount in its text to nops, and also to create
+ * an entry in the ftrace data. Now, if ftrace is activated
+ * after this call, but before the module sets its text to
+ * read-only, the modification of enabling ftrace can fail if
+ * the read-only is done while ftrace is converting the calls.
+ * To prevent this, the module's records are set as disabled
+ * and will be enabled after the call to set the module's text
+ * to read-only.
*/
- if (mod) {
- struct ftrace_ops *ops;
-
- for (ops = ftrace_ops_list;
- ops != &ftrace_list_end; ops = ops->next) {
- if (ops->flags & FTRACE_OPS_FL_ENABLED) {
- if (ops_traces_mod(ops))
- ref++;
- else
- test = true;
- }
- }
- }
-
- start = ftrace_now(raw_smp_processor_id());
+ if (mod)
+ rec_flags |= FTRACE_FL_DISABLED;
for (pg = new_pgs; pg; pg = pg->next) {
for (i = 0; i < pg->index; i++) {
- int cnt = ref;
/* If something went wrong, bail without enabling anything */
if (unlikely(ftrace_disabled))
return -1;
p = &pg->records[i];
- if (test)
- cnt += referenced_filters(p);
- p->flags = cnt;
+ p->flags = rec_flags;
/*
* Do the initial record conversion from mcount jump
@@ -2881,21 +2899,6 @@ static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
break;
update_cnt++;
-
- /*
- * If the tracing is enabled, go ahead and enable the record.
- *
- * The reason not to enable the record immediatelly is the
- * inherent check of ftrace_make_nop/ftrace_make_call for
- * correct previous instructions. Making first the NOP
- * conversion puts the module to the correct state, thus
- * passing the ftrace_make_call check.
- */
- if (ftrace_start_up && cnt) {
- int failed = __ftrace_replace_code(p, 1);
- if (failed)
- ftrace_bug(failed, p);
- }
}
}
@@ -3258,7 +3261,7 @@ static int t_show(struct seq_file *m, void *v)
seq_printf(m, "%ps", (void *)rec->ip);
if (iter->flags & FTRACE_ITER_ENABLED) {
- struct ftrace_ops *ops = NULL;
+ struct ftrace_ops *ops;
seq_printf(m, " (%ld)%s%s",
ftrace_rec_count(rec),
@@ -3266,14 +3269,19 @@ static int t_show(struct seq_file *m, void *v)
rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ");
if (rec->flags & FTRACE_FL_TRAMP_EN) {
ops = ftrace_find_tramp_ops_any(rec);
- if (ops)
- seq_printf(m, "\ttramp: %pS",
- (void *)ops->trampoline);
- else
+ if (ops) {
+ do {
+ seq_printf(m, "\ttramp: %pS (%pS)",
+ (void *)ops->trampoline,
+ (void *)ops->func);
+ add_trampoline_func(m, ops, rec);
+ ops = ftrace_find_tramp_ops_next(rec, ops);
+ } while (ops);
+ } else
seq_puts(m, "\ttramp: ERROR!");
-
+ } else {
+ add_trampoline_func(m, NULL, rec);
}
- add_trampoline_func(m, ops, rec);
}
seq_putc(m, '\n');
@@ -4898,6 +4906,19 @@ static int ftrace_process_locs(struct module *mod,
#define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
+static int referenced_filters(struct dyn_ftrace *rec)
+{
+ struct ftrace_ops *ops;
+ int cnt = 0;
+
+ for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
+ if (ops_references_rec(ops, rec))
+ cnt++;
+ }
+
+ return cnt;
+}
+
void ftrace_release_mod(struct module *mod)
{
struct dyn_ftrace *rec;
@@ -4940,41 +4961,112 @@ void ftrace_release_mod(struct module *mod)
mutex_unlock(&ftrace_lock);
}
-static void ftrace_init_module(struct module *mod,
- unsigned long *start, unsigned long *end)
+static void ftrace_module_enable(struct module *mod)
{
- if (ftrace_disabled || start == end)
- return;
- ftrace_process_locs(mod, start, end);
+ struct dyn_ftrace *rec;
+ struct ftrace_page *pg;
+
+ mutex_lock(&ftrace_lock);
+
+ if (ftrace_disabled)
+ goto out_unlock;
+
+ /*
+ * If the tracing is enabled, go ahead and enable the record.
+ *
+ * The reason not to enable the record immediatelly is the
+ * inherent check of ftrace_make_nop/ftrace_make_call for
+ * correct previous instructions. Making first the NOP
+ * conversion puts the module to the correct state, thus
+ * passing the ftrace_make_call check.
+ *
+ * We also delay this to after the module code already set the
+ * text to read-only, as we now need to set it back to read-write
+ * so that we can modify the text.
+ */
+ if (ftrace_start_up)
+ ftrace_arch_code_modify_prepare();
+
+ do_for_each_ftrace_rec(pg, rec) {
+ int cnt;
+ /*
+ * do_for_each_ftrace_rec() is a double loop.
+ * module text shares the pg. If a record is
+ * not part of this module, then skip this pg,
+ * which the "break" will do.
+ */
+ if (!within_module_core(rec->ip, mod))
+ break;
+
+ cnt = 0;
+
+ /*
+ * When adding a module, we need to check if tracers are
+ * currently enabled and if they are, and can trace this record,
+ * we need to enable the module functions as well as update the
+ * reference counts for those function records.
+ */
+ if (ftrace_start_up)
+ cnt += referenced_filters(rec);
+
+ /* This clears FTRACE_FL_DISABLED */
+ rec->flags = cnt;
+
+ if (ftrace_start_up && cnt) {
+ int failed = __ftrace_replace_code(rec, 1);
+ if (failed) {
+ ftrace_bug(failed, rec);
+ goto out_loop;
+ }
+ }
+
+ } while_for_each_ftrace_rec();
+
+ out_loop:
+ if (ftrace_start_up)
+ ftrace_arch_code_modify_post_process();
+
+ out_unlock:
+ mutex_unlock(&ftrace_lock);
}
void ftrace_module_init(struct module *mod)
{
- ftrace_init_module(mod, mod->ftrace_callsites,
- mod->ftrace_callsites +
- mod->num_ftrace_callsites);
+ if (ftrace_disabled || !mod->num_ftrace_callsites)
+ return;
+
+ ftrace_process_locs(mod, mod->ftrace_callsites,
+ mod->ftrace_callsites + mod->num_ftrace_callsites);
}
-static int ftrace_module_notify_exit(struct notifier_block *self,
- unsigned long val, void *data)
+static int ftrace_module_notify(struct notifier_block *self,
+ unsigned long val, void *data)
{
struct module *mod = data;
- if (val == MODULE_STATE_GOING)
+ switch (val) {
+ case MODULE_STATE_COMING:
+ ftrace_module_enable(mod);
+ break;
+ case MODULE_STATE_GOING:
ftrace_release_mod(mod);
+ break;
+ default:
+ break;
+ }
return 0;
}
#else
-static int ftrace_module_notify_exit(struct notifier_block *self,
- unsigned long val, void *data)
+static int ftrace_module_notify(struct notifier_block *self,
+ unsigned long val, void *data)
{
return 0;
}
#endif /* CONFIG_MODULES */
-struct notifier_block ftrace_module_exit_nb = {
- .notifier_call = ftrace_module_notify_exit,
+struct notifier_block ftrace_module_nb = {
+ .notifier_call = ftrace_module_notify,
.priority = INT_MIN, /* Run after anything that can remove kprobes */
};
@@ -5006,7 +5098,7 @@ void __init ftrace_init(void)
__start_mcount_loc,
__stop_mcount_loc);
- ret = register_module_notifier(&ftrace_module_exit_nb);
+ ret = register_module_notifier(&ftrace_module_nb);
if (ret)
pr_warning("Failed to register trace ftrace module exit notifier\n");
@@ -5116,44 +5208,6 @@ void ftrace_reset_array_ops(struct trace_array *tr)
tr->ops->func = ftrace_stub;
}
-static void
-ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip,
- struct ftrace_ops *op, struct pt_regs *regs)
-{
- if (unlikely(trace_recursion_test(TRACE_CONTROL_BIT)))
- return;
-
- /*
- * Some of the ops may be dynamically allocated,
- * they must be freed after a synchronize_sched().
- */
- preempt_disable_notrace();
- trace_recursion_set(TRACE_CONTROL_BIT);
-
- /*
- * Control funcs (perf) uses RCU. Only trace if
- * RCU is currently active.
- */
- if (!rcu_is_watching())
- goto out;
-
- do_for_each_ftrace_op(op, ftrace_control_list) {
- if (!(op->flags & FTRACE_OPS_FL_STUB) &&
- !ftrace_function_local_disabled(op) &&
- ftrace_ops_test(op, ip, regs))
- op->func(ip, parent_ip, op, regs);
- } while_for_each_ftrace_op(op);
- out:
- trace_recursion_clear(TRACE_CONTROL_BIT);
- preempt_enable_notrace();
-}
-
-static struct ftrace_ops control_ops = {
- .func = ftrace_ops_control_func,
- .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
- INIT_OPS_HASH(control_ops)
-};
-
static inline void
__ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *ignored, struct pt_regs *regs)
@@ -5170,8 +5224,22 @@ __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
* they must be freed after a synchronize_sched().
*/
preempt_disable_notrace();
+
do_for_each_ftrace_op(op, ftrace_ops_list) {
- if (ftrace_ops_test(op, ip, regs)) {
+ /*
+ * Check the following for each ops before calling their func:
+ * if RCU flag is set, then rcu_is_watching() must be true
+ * if PER_CPU is set, then ftrace_function_local_disable()
+ * must be false
+ * Otherwise test if the ip matches the ops filter
+ *
+ * If any of the above fails then the op->func() is not executed.
+ */
+ if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
+ (!(op->flags & FTRACE_OPS_FL_PER_CPU) ||
+ !ftrace_function_local_disabled(op)) &&
+ ftrace_ops_test(op, ip, regs)) {
+
if (FTRACE_WARN_ON(!op->func)) {
pr_warn("op=%p %pS\n", op, op);
goto out;
@@ -5195,7 +5263,7 @@ out:
* being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
* Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
* An architecture can pass partial regs with ftrace_ops and still
- * set the ARCH_SUPPORT_FTARCE_OPS.
+ * set the ARCH_SUPPORTS_FTRACE_OPS.
*/
#if ARCH_SUPPORTS_FTRACE_OPS
static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
@@ -5212,20 +5280,29 @@ static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
/*
* If there's only one function registered but it does not support
- * recursion, this function will be called by the mcount trampoline.
- * This function will handle recursion protection.
+ * recursion, needs RCU protection and/or requires per cpu handling, then
+ * this function will be called by the mcount trampoline.
*/
-static void ftrace_ops_recurs_func(unsigned long ip, unsigned long parent_ip,
+static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct pt_regs *regs)
{
int bit;
+ if ((op->flags & FTRACE_OPS_FL_RCU) && !rcu_is_watching())
+ return;
+
bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
if (bit < 0)
return;
- op->func(ip, parent_ip, op, regs);
+ preempt_disable_notrace();
+ if (!(op->flags & FTRACE_OPS_FL_PER_CPU) ||
+ !ftrace_function_local_disabled(op)) {
+ op->func(ip, parent_ip, op, regs);
+ }
+
+ preempt_enable_notrace();
trace_clear_recursion(bit);
}
@@ -5243,12 +5320,12 @@ static void ftrace_ops_recurs_func(unsigned long ip, unsigned long parent_ip,
ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
{
/*
- * If the func handles its own recursion, call it directly.
- * Otherwise call the recursion protected function that
- * will call the ftrace ops function.
+ * If the function does not handle recursion, needs to be RCU safe,
+ * or does per cpu logic, then we need to call the assist handler.
*/
- if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE))
- return ftrace_ops_recurs_func;
+ if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) ||
+ ops->flags & (FTRACE_OPS_FL_RCU | FTRACE_OPS_FL_PER_CPU))
+ return ftrace_ops_assist_func;
return ops->func;
}
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 75f1d05ea82d..95181e36891a 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1001,17 +1001,13 @@ static int rb_head_page_replace(struct buffer_page *old,
/*
* rb_tail_page_update - move the tail page forward
- *
- * Returns 1 if moved tail page, 0 if someone else did.
*/
-static int rb_tail_page_update(struct ring_buffer_per_cpu *cpu_buffer,
+static void rb_tail_page_update(struct ring_buffer_per_cpu *cpu_buffer,
struct buffer_page *tail_page,
struct buffer_page *next_page)
{
- struct buffer_page *old_tail;
unsigned long old_entries;
unsigned long old_write;
- int ret = 0;
/*
* The tail page now needs to be moved forward.
@@ -1036,7 +1032,7 @@ static int rb_tail_page_update(struct ring_buffer_per_cpu *cpu_buffer,
* it is, then it is up to us to update the tail
* pointer.
*/
- if (tail_page == cpu_buffer->tail_page) {
+ if (tail_page == READ_ONCE(cpu_buffer->tail_page)) {
/* Zero the write counter */
unsigned long val = old_write & ~RB_WRITE_MASK;
unsigned long eval = old_entries & ~RB_WRITE_MASK;
@@ -1061,14 +1057,9 @@ static int rb_tail_page_update(struct ring_buffer_per_cpu *cpu_buffer,
*/
local_set(&next_page->page->commit, 0);
- old_tail = cmpxchg(&cpu_buffer->tail_page,
- tail_page, next_page);
-
- if (old_tail == tail_page)
- ret = 1;
+ /* Again, either we update tail_page or an interrupt does */
+ (void)cmpxchg(&cpu_buffer->tail_page, tail_page, next_page);
}
-
- return ret;
}
static int rb_check_bpage(struct ring_buffer_per_cpu *cpu_buffer,
@@ -1887,12 +1878,6 @@ rb_event_index(struct ring_buffer_event *event)
return (addr & ~PAGE_MASK) - BUF_PAGE_HDR_SIZE;
}
-static void rb_reset_reader_page(struct ring_buffer_per_cpu *cpu_buffer)
-{
- cpu_buffer->read_stamp = cpu_buffer->reader_page->page->time_stamp;
- cpu_buffer->reader_page->read = 0;
-}
-
static void rb_inc_iter(struct ring_buffer_iter *iter)
{
struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
@@ -2042,12 +2027,15 @@ rb_handle_head_page(struct ring_buffer_per_cpu *cpu_buffer,
* the tail page would have moved.
*/
if (ret == RB_PAGE_NORMAL) {
+ struct buffer_page *buffer_tail_page;
+
+ buffer_tail_page = READ_ONCE(cpu_buffer->tail_page);
/*
* If the tail had moved passed next, then we need
* to reset the pointer.
*/
- if (cpu_buffer->tail_page != tail_page &&
- cpu_buffer->tail_page != next_page)
+ if (buffer_tail_page != tail_page &&
+ buffer_tail_page != next_page)
rb_head_page_set_normal(cpu_buffer, new_head,
next_page,
RB_PAGE_HEAD);
@@ -2141,6 +2129,8 @@ rb_reset_tail(struct ring_buffer_per_cpu *cpu_buffer,
local_sub(length, &tail_page->write);
}
+static inline void rb_end_commit(struct ring_buffer_per_cpu *cpu_buffer);
+
/*
* This is the slow path, force gcc not to inline it.
*/
@@ -2153,7 +2143,6 @@ rb_move_tail(struct ring_buffer_per_cpu *cpu_buffer,
struct ring_buffer *buffer = cpu_buffer->buffer;
struct buffer_page *next_page;
int ret;
- u64 ts;
next_page = tail_page;
@@ -2227,20 +2216,17 @@ rb_move_tail(struct ring_buffer_per_cpu *cpu_buffer,
}
}
- ret = rb_tail_page_update(cpu_buffer, tail_page, next_page);
- if (ret) {
- /*
- * Nested commits always have zero deltas, so
- * just reread the time stamp
- */
- ts = rb_time_stamp(buffer);
- next_page->page->time_stamp = ts;
- }
+ rb_tail_page_update(cpu_buffer, tail_page, next_page);
out_again:
rb_reset_tail(cpu_buffer, tail, info);
+ /* Commit what we have for now. */
+ rb_end_commit(cpu_buffer);
+ /* rb_end_commit() decs committing */
+ local_inc(&cpu_buffer->committing);
+
/* fail and let the caller try again */
return ERR_PTR(-EAGAIN);
@@ -2368,7 +2354,7 @@ rb_try_to_discard(struct ring_buffer_per_cpu *cpu_buffer,
addr = (unsigned long)event;
addr &= PAGE_MASK;
- bpage = cpu_buffer->tail_page;
+ bpage = READ_ONCE(cpu_buffer->tail_page);
if (bpage->page == (void *)addr && rb_page_write(bpage) == old_index) {
unsigned long write_mask =
@@ -2416,7 +2402,7 @@ rb_set_commit_to_write(struct ring_buffer_per_cpu *cpu_buffer)
again:
max_count = cpu_buffer->nr_pages * 100;
- while (cpu_buffer->commit_page != cpu_buffer->tail_page) {
+ while (cpu_buffer->commit_page != READ_ONCE(cpu_buffer->tail_page)) {
if (RB_WARN_ON(cpu_buffer, !(--max_count)))
return;
if (RB_WARN_ON(cpu_buffer,
@@ -2425,8 +2411,10 @@ rb_set_commit_to_write(struct ring_buffer_per_cpu *cpu_buffer)
local_set(&cpu_buffer->commit_page->page->commit,
rb_page_write(cpu_buffer->commit_page));
rb_inc_page(cpu_buffer, &cpu_buffer->commit_page);
- cpu_buffer->write_stamp =
- cpu_buffer->commit_page->page->time_stamp;
+ /* Only update the write stamp if the page has an event */
+ if (rb_page_write(cpu_buffer->commit_page))
+ cpu_buffer->write_stamp =
+ cpu_buffer->commit_page->page->time_stamp;
/* add barrier to keep gcc from optimizing too much */
barrier();
}
@@ -2449,7 +2437,7 @@ rb_set_commit_to_write(struct ring_buffer_per_cpu *cpu_buffer)
* and pushed the tail page forward, we will be left with
* a dangling commit that will never go forward.
*/
- if (unlikely(cpu_buffer->commit_page != cpu_buffer->tail_page))
+ if (unlikely(cpu_buffer->commit_page != READ_ONCE(cpu_buffer->tail_page)))
goto again;
}
@@ -2705,7 +2693,8 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
if (unlikely(info->add_timestamp))
info->length += RB_LEN_TIME_EXTEND;
- tail_page = info->tail_page = cpu_buffer->tail_page;
+ /* Don't let the compiler play games with cpu_buffer->tail_page */
+ tail_page = info->tail_page = READ_ONCE(cpu_buffer->tail_page);
write = local_add_return(info->length, &tail_page->write);
/* set write to only the index of the write */
@@ -2803,8 +2792,11 @@ rb_reserve_next_event(struct ring_buffer *buffer,
event = __rb_reserve_next(cpu_buffer, &info);
- if (unlikely(PTR_ERR(event) == -EAGAIN))
+ if (unlikely(PTR_ERR(event) == -EAGAIN)) {
+ if (info.add_timestamp)
+ info.length -= RB_LEN_TIME_EXTEND;
goto again;
+ }
if (!event)
goto out_fail;
@@ -3626,7 +3618,7 @@ rb_get_reader_page(struct ring_buffer_per_cpu *cpu_buffer)
/* Finally update the reader page to the new head */
cpu_buffer->reader_page = reader;
- rb_reset_reader_page(cpu_buffer);
+ cpu_buffer->reader_page->read = 0;
if (overwrite != cpu_buffer->last_overrun) {
cpu_buffer->lost_events = overwrite - cpu_buffer->last_overrun;
@@ -3636,6 +3628,10 @@ rb_get_reader_page(struct ring_buffer_per_cpu *cpu_buffer)
goto again;
out:
+ /* Update the read_stamp on the first event */
+ if (reader && reader->read == 0)
+ cpu_buffer->read_stamp = reader->page->time_stamp;
+
arch_spin_unlock(&cpu_buffer->lock);
local_irq_restore(flags);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 919d9d07686f..8414fa40bf27 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -363,8 +363,8 @@ struct trace_option_dentry {
* @name: the name chosen to select it on the available_tracers file
* @init: called when one switches to this tracer (echo name > current_tracer)
* @reset: called when one switches to another tracer
- * @start: called when tracing is unpaused (echo 1 > tracing_enabled)
- * @stop: called when tracing is paused (echo 0 > tracing_enabled)
+ * @start: called when tracing is unpaused (echo 1 > tracing_on)
+ * @stop: called when tracing is paused (echo 0 > tracing_on)
* @update_thresh: called when tracing_thresh is updated
* @open: called when the trace file is opened
* @pipe_open: called when the trace_pipe file is opened
@@ -467,8 +467,6 @@ enum {
TRACE_INTERNAL_IRQ_BIT,
TRACE_INTERNAL_SIRQ_BIT,
- TRACE_CONTROL_BIT,
-
TRACE_BRANCH_BIT,
/*
* Abuse of the trace_recursion.
diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index abfc903e741e..2649c85cd162 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -334,7 +334,7 @@ static int perf_ftrace_function_register(struct perf_event *event)
{
struct ftrace_ops *ops = &event->ftrace_ops;
- ops->flags |= FTRACE_OPS_FL_CONTROL;
+ ops->flags |= FTRACE_OPS_FL_PER_CPU | FTRACE_OPS_FL_RCU;
ops->func = perf_ftrace_function_call;
return register_ftrace_function(ops);
}
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index 42a4009fd75a..4d2f3ccc56f6 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -543,11 +543,12 @@ static int register_trigger(char *glob, struct event_trigger_ops *ops,
list_add_rcu(&data->list, &file->triggers);
ret++;
+ update_cond_flag(file);
if (trace_event_trigger_enable_disable(file, 1) < 0) {
list_del_rcu(&data->list);
+ update_cond_flag(file);
ret--;
}
- update_cond_flag(file);
out:
return ret;
}
@@ -575,8 +576,8 @@ static void unregister_trigger(char *glob, struct event_trigger_ops *ops,
if (data->cmd_ops->trigger_type == test->cmd_ops->trigger_type) {
unregistered = true;
list_del_rcu(&data->list);
- update_cond_flag(file);
trace_event_trigger_enable_disable(file, 0);
+ update_cond_flag(file);
break;
}
}
@@ -1319,11 +1320,12 @@ static int event_enable_register_trigger(char *glob,
list_add_rcu(&data->list, &file->triggers);
ret++;
+ update_cond_flag(file);
if (trace_event_trigger_enable_disable(file, 1) < 0) {
list_del_rcu(&data->list);
+ update_cond_flag(file);
ret--;
}
- update_cond_flag(file);
out:
return ret;
}
@@ -1344,8 +1346,8 @@ static void event_enable_unregister_trigger(char *glob,
(enable_data->file == test_enable_data->file)) {
unregistered = true;
list_del_rcu(&data->list);
- update_cond_flag(file);
trace_event_trigger_enable_disable(file, 0);
+ update_cond_flag(file);
break;
}
}
diff --git a/lib/seq_buf.c b/lib/seq_buf.c
index 5c94e1012a91..cb18469e1f49 100644
--- a/lib/seq_buf.c
+++ b/lib/seq_buf.c
@@ -306,10 +306,12 @@ int seq_buf_to_user(struct seq_buf *s, char __user *ubuf, int cnt)
if (!cnt)
return 0;
- if (s->len <= s->readpos)
+ len = seq_buf_used(s);
+
+ if (len <= s->readpos)
return -EBUSY;
- len = seq_buf_used(s) - s->readpos;
+ len -= s->readpos;
if (cnt > len)
cnt = len;
ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
diff --git a/tools/testing/selftests/ftrace/test.d/instances/instance.tc b/tools/testing/selftests/ftrace/test.d/instances/instance.tc
new file mode 100644
index 000000000000..773e276ff90b
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/instances/instance.tc
@@ -0,0 +1,90 @@
+#!/bin/sh
+# description: Test creation and deletion of trace instances
+
+if [ ! -d instances ] ; then
+ echo "no instance directory with this kernel"
+ exit_unsupported;
+fi
+
+fail() { # mesg
+ rmdir x y z 2>/dev/null
+ echo $1
+ set -e
+ exit $FAIL
+}
+
+cd instances
+
+# we don't want to fail on error
+set +e
+
+mkdir x
+rmdir x
+result=$?
+
+if [ $result -ne 0 ]; then
+ echo "instance rmdir not supported"
+ exit_unsupported
+fi
+
+instance_slam() {
+ while :; do
+ mkdir x
+ mkdir y
+ mkdir z
+ rmdir x
+ rmdir y
+ rmdir z
+ done 2>/dev/null
+}
+
+instance_slam &
+x=`jobs -l`
+p1=`echo $x | cut -d' ' -f2`
+echo $p1
+
+instance_slam &
+x=`jobs -l | tail -1`
+p2=`echo $x | cut -d' ' -f2`
+echo $p2
+
+instance_slam &
+x=`jobs -l | tail -1`
+p3=`echo $x | cut -d' ' -f2`
+echo $p3
+
+instance_slam &
+x=`jobs -l | tail -1`
+p4=`echo $x | cut -d' ' -f2`
+echo $p4
+
+instance_slam &
+x=`jobs -l | tail -1`
+p5=`echo $x | cut -d' ' -f2`
+echo $p5
+
+ls -lR >/dev/null
+sleep 1
+
+kill -1 $p1
+kill -1 $p2
+kill -1 $p3
+kill -1 $p4
+kill -1 $p5
+
+echo "Wait for processes to finish"
+wait $p1 $p2 $p3 $p4 $p5
+echo "all processes finished, wait for cleanup"
+
+mkdir x y z
+ls x y z
+rmdir x y z
+for d in x y z; do
+ if [ -d $d ]; then
+ fail "instance $d still exists"
+ fi
+done
+
+set -e
+
+exit 0
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