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authorLinus Torvalds <torvalds@linux-foundation.org>2013-07-29 01:10:39 (GMT)
committerLinus Torvalds <torvalds@linux-foundation.org>2013-07-29 01:10:39 (GMT)
commit6803f37e0955c7cc7ebe4363cf2bab5552e4716d (patch)
treeff4dc956f564b3b94fce96ed08609f561ca1c646
parent561d9e8185883a8d0788cb15090873d4f13323f5 (diff)
parent09d8091c024ec88d1541d93eb8ddb2bd5cf10c39 (diff)
Merge tag 'trace-fixes-3.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt: "Oleg is working on fixing a very tight race between opening a event file and deleting that event at the same time (both must be done as root). I also found a bug while testing Oleg's patches which has to do with a race with kprobes using the function tracer. There's also a deadlock fix that was introduced with the previous fixes" * tag 'trace-fixes-3.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing: Remove locking trace_types_lock from tracing_reset_all_online_cpus() ftrace: Add check for NULL regs if ops has SAVE_REGS set tracing: Kill trace_cpu struct/members tracing: Change tracing_fops/snapshot_fops to rely on tracing_get_cpu() tracing: Change tracing_entries_fops to rely on tracing_get_cpu() tracing: Change tracing_stats_fops to rely on tracing_get_cpu() tracing: Change tracing_buffers_fops to rely on tracing_get_cpu() tracing: Change tracing_pipe_fops() to rely on tracing_get_cpu() tracing: Introduce trace_create_cpu_file() and tracing_get_cpu()
-rw-r--r--kernel/trace/ftrace.c18
-rw-r--r--kernel/trace/trace.c197
-rw-r--r--kernel/trace/trace.h8
3 files changed, 95 insertions, 128 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 67708f4..8ce9eefc 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1441,12 +1441,22 @@ ftrace_hash_move(struct ftrace_ops *ops, int enable,
* the hashes are freed with call_rcu_sched().
*/
static int
-ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
+ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
{
struct ftrace_hash *filter_hash;
struct ftrace_hash *notrace_hash;
int ret;
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+ /*
+ * There's a small race when adding ops that the ftrace handler
+ * that wants regs, may be called without them. We can not
+ * allow that handler to be called if regs is NULL.
+ */
+ if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
+ return 0;
+#endif
+
filter_hash = rcu_dereference_raw_notrace(ops->filter_hash);
notrace_hash = rcu_dereference_raw_notrace(ops->notrace_hash);
@@ -4218,7 +4228,7 @@ static inline void ftrace_startup_enable(int command) { }
# define ftrace_shutdown_sysctl() do { } while (0)
static inline int
-ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
+ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
{
return 1;
}
@@ -4241,7 +4251,7 @@ ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip,
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))
+ ftrace_ops_test(op, ip, regs))
op->func(ip, parent_ip, op, regs);
} while_for_each_ftrace_op(op);
trace_recursion_clear(TRACE_CONTROL_BIT);
@@ -4274,7 +4284,7 @@ __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
*/
preempt_disable_notrace();
do_for_each_ftrace_op(op, ftrace_ops_list) {
- if (ftrace_ops_test(op, ip))
+ if (ftrace_ops_test(op, ip, regs))
op->func(ip, parent_ip, op, regs);
} while_for_each_ftrace_op(op);
preempt_enable_notrace();
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 3f24777..882ec1d 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1224,18 +1224,17 @@ void tracing_reset_current(int cpu)
tracing_reset(&global_trace.trace_buffer, cpu);
}
+/* Must have trace_types_lock held */
void tracing_reset_all_online_cpus(void)
{
struct trace_array *tr;
- mutex_lock(&trace_types_lock);
list_for_each_entry(tr, &ftrace_trace_arrays, list) {
tracing_reset_online_cpus(&tr->trace_buffer);
#ifdef CONFIG_TRACER_MAX_TRACE
tracing_reset_online_cpus(&tr->max_buffer);
#endif
}
- mutex_unlock(&trace_types_lock);
}
#define SAVED_CMDLINES 128
@@ -2843,6 +2842,17 @@ static int s_show(struct seq_file *m, void *v)
return 0;
}
+/*
+ * Should be used after trace_array_get(), trace_types_lock
+ * ensures that i_cdev was already initialized.
+ */
+static inline int tracing_get_cpu(struct inode *inode)
+{
+ if (inode->i_cdev) /* See trace_create_cpu_file() */
+ return (long)inode->i_cdev - 1;
+ return RING_BUFFER_ALL_CPUS;
+}
+
static const struct seq_operations tracer_seq_ops = {
.start = s_start,
.next = s_next,
@@ -2851,9 +2861,9 @@ static const struct seq_operations tracer_seq_ops = {
};
static struct trace_iterator *
-__tracing_open(struct trace_array *tr, struct trace_cpu *tc,
- struct inode *inode, struct file *file, bool snapshot)
+__tracing_open(struct inode *inode, struct file *file, bool snapshot)
{
+ struct trace_array *tr = inode->i_private;
struct trace_iterator *iter;
int cpu;
@@ -2894,8 +2904,8 @@ __tracing_open(struct trace_array *tr, struct trace_cpu *tc,
iter->trace_buffer = &tr->trace_buffer;
iter->snapshot = snapshot;
iter->pos = -1;
+ iter->cpu_file = tracing_get_cpu(inode);
mutex_init(&iter->mutex);
- iter->cpu_file = tc->cpu;
/* Notify the tracer early; before we stop tracing. */
if (iter->trace && iter->trace->open)
@@ -2971,44 +2981,22 @@ static int tracing_open_generic_tr(struct inode *inode, struct file *filp)
filp->private_data = inode->i_private;
return 0;
-
-}
-
-static int tracing_open_generic_tc(struct inode *inode, struct file *filp)
-{
- struct trace_cpu *tc = inode->i_private;
- struct trace_array *tr = tc->tr;
-
- if (tracing_disabled)
- return -ENODEV;
-
- if (trace_array_get(tr) < 0)
- return -ENODEV;
-
- filp->private_data = inode->i_private;
-
- return 0;
-
}
static int tracing_release(struct inode *inode, struct file *file)
{
+ struct trace_array *tr = inode->i_private;
struct seq_file *m = file->private_data;
struct trace_iterator *iter;
- struct trace_array *tr;
int cpu;
- /* Writes do not use seq_file, need to grab tr from inode */
if (!(file->f_mode & FMODE_READ)) {
- struct trace_cpu *tc = inode->i_private;
-
- trace_array_put(tc->tr);
+ trace_array_put(tr);
return 0;
}
+ /* Writes do not use seq_file */
iter = m->private;
- tr = iter->tr;
-
mutex_lock(&trace_types_lock);
for_each_tracing_cpu(cpu) {
@@ -3044,15 +3032,6 @@ static int tracing_release_generic_tr(struct inode *inode, struct file *file)
return 0;
}
-static int tracing_release_generic_tc(struct inode *inode, struct file *file)
-{
- struct trace_cpu *tc = inode->i_private;
- struct trace_array *tr = tc->tr;
-
- trace_array_put(tr);
- return 0;
-}
-
static int tracing_single_release_tr(struct inode *inode, struct file *file)
{
struct trace_array *tr = inode->i_private;
@@ -3064,8 +3043,7 @@ static int tracing_single_release_tr(struct inode *inode, struct file *file)
static int tracing_open(struct inode *inode, struct file *file)
{
- struct trace_cpu *tc = inode->i_private;
- struct trace_array *tr = tc->tr;
+ struct trace_array *tr = inode->i_private;
struct trace_iterator *iter;
int ret = 0;
@@ -3073,16 +3051,17 @@ static int tracing_open(struct inode *inode, struct file *file)
return -ENODEV;
/* If this file was open for write, then erase contents */
- if ((file->f_mode & FMODE_WRITE) &&
- (file->f_flags & O_TRUNC)) {
- if (tc->cpu == RING_BUFFER_ALL_CPUS)
+ if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
+ int cpu = tracing_get_cpu(inode);
+
+ if (cpu == RING_BUFFER_ALL_CPUS)
tracing_reset_online_cpus(&tr->trace_buffer);
else
- tracing_reset(&tr->trace_buffer, tc->cpu);
+ tracing_reset(&tr->trace_buffer, cpu);
}
if (file->f_mode & FMODE_READ) {
- iter = __tracing_open(tr, tc, inode, file, false);
+ iter = __tracing_open(inode, file, false);
if (IS_ERR(iter))
ret = PTR_ERR(iter);
else if (trace_flags & TRACE_ITER_LATENCY_FMT)
@@ -3948,8 +3927,7 @@ tracing_max_lat_write(struct file *filp, const char __user *ubuf,
static int tracing_open_pipe(struct inode *inode, struct file *filp)
{
- struct trace_cpu *tc = inode->i_private;
- struct trace_array *tr = tc->tr;
+ struct trace_array *tr = inode->i_private;
struct trace_iterator *iter;
int ret = 0;
@@ -3995,9 +3973,9 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp)
if (trace_clocks[tr->clock_id].in_ns)
iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
- iter->cpu_file = tc->cpu;
- iter->tr = tc->tr;
- iter->trace_buffer = &tc->tr->trace_buffer;
+ iter->tr = tr;
+ iter->trace_buffer = &tr->trace_buffer;
+ iter->cpu_file = tracing_get_cpu(inode);
mutex_init(&iter->mutex);
filp->private_data = iter;
@@ -4020,8 +3998,7 @@ fail:
static int tracing_release_pipe(struct inode *inode, struct file *file)
{
struct trace_iterator *iter = file->private_data;
- struct trace_cpu *tc = inode->i_private;
- struct trace_array *tr = tc->tr;
+ struct trace_array *tr = inode->i_private;
mutex_lock(&trace_types_lock);
@@ -4374,15 +4351,16 @@ static ssize_t
tracing_entries_read(struct file *filp, char __user *ubuf,
size_t cnt, loff_t *ppos)
{
- struct trace_cpu *tc = filp->private_data;
- struct trace_array *tr = tc->tr;
+ struct inode *inode = file_inode(filp);
+ struct trace_array *tr = inode->i_private;
+ int cpu = tracing_get_cpu(inode);
char buf[64];
int r = 0;
ssize_t ret;
mutex_lock(&trace_types_lock);
- if (tc->cpu == RING_BUFFER_ALL_CPUS) {
+ if (cpu == RING_BUFFER_ALL_CPUS) {
int cpu, buf_size_same;
unsigned long size;
@@ -4409,7 +4387,7 @@ tracing_entries_read(struct file *filp, char __user *ubuf,
} else
r = sprintf(buf, "X\n");
} else
- r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->trace_buffer.data, tc->cpu)->entries >> 10);
+ r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->trace_buffer.data, cpu)->entries >> 10);
mutex_unlock(&trace_types_lock);
@@ -4421,7 +4399,8 @@ static ssize_t
tracing_entries_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
- struct trace_cpu *tc = filp->private_data;
+ struct inode *inode = file_inode(filp);
+ struct trace_array *tr = inode->i_private;
unsigned long val;
int ret;
@@ -4435,8 +4414,7 @@ tracing_entries_write(struct file *filp, const char __user *ubuf,
/* value is in KB */
val <<= 10;
-
- ret = tracing_resize_ring_buffer(tc->tr, val, tc->cpu);
+ ret = tracing_resize_ring_buffer(tr, val, tracing_get_cpu(inode));
if (ret < 0)
return ret;
@@ -4697,8 +4675,7 @@ struct ftrace_buffer_info {
#ifdef CONFIG_TRACER_SNAPSHOT
static int tracing_snapshot_open(struct inode *inode, struct file *file)
{
- struct trace_cpu *tc = inode->i_private;
- struct trace_array *tr = tc->tr;
+ struct trace_array *tr = inode->i_private;
struct trace_iterator *iter;
struct seq_file *m;
int ret = 0;
@@ -4707,7 +4684,7 @@ static int tracing_snapshot_open(struct inode *inode, struct file *file)
return -ENODEV;
if (file->f_mode & FMODE_READ) {
- iter = __tracing_open(tr, tc, inode, file, true);
+ iter = __tracing_open(inode, file, true);
if (IS_ERR(iter))
ret = PTR_ERR(iter);
} else {
@@ -4724,8 +4701,8 @@ static int tracing_snapshot_open(struct inode *inode, struct file *file)
ret = 0;
iter->tr = tr;
- iter->trace_buffer = &tc->tr->max_buffer;
- iter->cpu_file = tc->cpu;
+ iter->trace_buffer = &tr->max_buffer;
+ iter->cpu_file = tracing_get_cpu(inode);
m->private = iter;
file->private_data = m;
}
@@ -4884,11 +4861,11 @@ static const struct file_operations tracing_pipe_fops = {
};
static const struct file_operations tracing_entries_fops = {
- .open = tracing_open_generic_tc,
+ .open = tracing_open_generic_tr,
.read = tracing_entries_read,
.write = tracing_entries_write,
.llseek = generic_file_llseek,
- .release = tracing_release_generic_tc,
+ .release = tracing_release_generic_tr,
};
static const struct file_operations tracing_total_entries_fops = {
@@ -4940,8 +4917,7 @@ static const struct file_operations snapshot_raw_fops = {
static int tracing_buffers_open(struct inode *inode, struct file *filp)
{
- struct trace_cpu *tc = inode->i_private;
- struct trace_array *tr = tc->tr;
+ struct trace_array *tr = inode->i_private;
struct ftrace_buffer_info *info;
int ret;
@@ -4960,7 +4936,7 @@ static int tracing_buffers_open(struct inode *inode, struct file *filp)
mutex_lock(&trace_types_lock);
info->iter.tr = tr;
- info->iter.cpu_file = tc->cpu;
+ info->iter.cpu_file = tracing_get_cpu(inode);
info->iter.trace = tr->current_trace;
info->iter.trace_buffer = &tr->trace_buffer;
info->spare = NULL;
@@ -5277,14 +5253,14 @@ static ssize_t
tracing_stats_read(struct file *filp, char __user *ubuf,
size_t count, loff_t *ppos)
{
- struct trace_cpu *tc = filp->private_data;
- struct trace_array *tr = tc->tr;
+ struct inode *inode = file_inode(filp);
+ struct trace_array *tr = inode->i_private;
struct trace_buffer *trace_buf = &tr->trace_buffer;
+ int cpu = tracing_get_cpu(inode);
struct trace_seq *s;
unsigned long cnt;
unsigned long long t;
unsigned long usec_rem;
- int cpu = tc->cpu;
s = kmalloc(sizeof(*s), GFP_KERNEL);
if (!s)
@@ -5337,10 +5313,10 @@ tracing_stats_read(struct file *filp, char __user *ubuf,
}
static const struct file_operations tracing_stats_fops = {
- .open = tracing_open_generic_tc,
+ .open = tracing_open_generic_tr,
.read = tracing_stats_read,
.llseek = generic_file_llseek,
- .release = tracing_release_generic_tc,
+ .release = tracing_release_generic_tr,
};
#ifdef CONFIG_DYNAMIC_FTRACE
@@ -5529,10 +5505,20 @@ static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
return tr->percpu_dir;
}
+static struct dentry *
+trace_create_cpu_file(const char *name, umode_t mode, struct dentry *parent,
+ void *data, long cpu, const struct file_operations *fops)
+{
+ struct dentry *ret = trace_create_file(name, mode, parent, data, fops);
+
+ if (ret) /* See tracing_get_cpu() */
+ ret->d_inode->i_cdev = (void *)(cpu + 1);
+ return ret;
+}
+
static void
tracing_init_debugfs_percpu(struct trace_array *tr, long cpu)
{
- struct trace_array_cpu *data = per_cpu_ptr(tr->trace_buffer.data, cpu);
struct dentry *d_percpu = tracing_dentry_percpu(tr, cpu);
struct dentry *d_cpu;
char cpu_dir[30]; /* 30 characters should be more than enough */
@@ -5548,28 +5534,28 @@ tracing_init_debugfs_percpu(struct trace_array *tr, long cpu)
}
/* per cpu trace_pipe */
- trace_create_file("trace_pipe", 0444, d_cpu,
- (void *)&data->trace_cpu, &tracing_pipe_fops);
+ trace_create_cpu_file("trace_pipe", 0444, d_cpu,
+ tr, cpu, &tracing_pipe_fops);
/* per cpu trace */
- trace_create_file("trace", 0644, d_cpu,
- (void *)&data->trace_cpu, &tracing_fops);
+ trace_create_cpu_file("trace", 0644, d_cpu,
+ tr, cpu, &tracing_fops);
- trace_create_file("trace_pipe_raw", 0444, d_cpu,
- (void *)&data->trace_cpu, &tracing_buffers_fops);
+ trace_create_cpu_file("trace_pipe_raw", 0444, d_cpu,
+ tr, cpu, &tracing_buffers_fops);
- trace_create_file("stats", 0444, d_cpu,
- (void *)&data->trace_cpu, &tracing_stats_fops);
+ trace_create_cpu_file("stats", 0444, d_cpu,
+ tr, cpu, &tracing_stats_fops);
- trace_create_file("buffer_size_kb", 0444, d_cpu,
- (void *)&data->trace_cpu, &tracing_entries_fops);
+ trace_create_cpu_file("buffer_size_kb", 0444, d_cpu,
+ tr, cpu, &tracing_entries_fops);
#ifdef CONFIG_TRACER_SNAPSHOT
- trace_create_file("snapshot", 0644, d_cpu,
- (void *)&data->trace_cpu, &snapshot_fops);
+ trace_create_cpu_file("snapshot", 0644, d_cpu,
+ tr, cpu, &snapshot_fops);
- trace_create_file("snapshot_raw", 0444, d_cpu,
- (void *)&data->trace_cpu, &snapshot_raw_fops);
+ trace_create_cpu_file("snapshot_raw", 0444, d_cpu,
+ tr, cpu, &snapshot_raw_fops);
#endif
}
@@ -5878,17 +5864,6 @@ struct dentry *trace_instance_dir;
static void
init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer);
-static void init_trace_buffers(struct trace_array *tr, struct trace_buffer *buf)
-{
- int cpu;
-
- for_each_tracing_cpu(cpu) {
- memset(per_cpu_ptr(buf->data, cpu), 0, sizeof(struct trace_array_cpu));
- per_cpu_ptr(buf->data, cpu)->trace_cpu.cpu = cpu;
- per_cpu_ptr(buf->data, cpu)->trace_cpu.tr = tr;
- }
-}
-
static int
allocate_trace_buffer(struct trace_array *tr, struct trace_buffer *buf, int size)
{
@@ -5906,8 +5881,6 @@ allocate_trace_buffer(struct trace_array *tr, struct trace_buffer *buf, int size
return -ENOMEM;
}
- init_trace_buffers(tr, buf);
-
/* Allocate the first page for all buffers */
set_buffer_entries(&tr->trace_buffer,
ring_buffer_size(tr->trace_buffer.buffer, 0));
@@ -5974,10 +5947,6 @@ static int new_instance_create(const char *name)
if (allocate_trace_buffers(tr, trace_buf_size) < 0)
goto out_free_tr;
- /* Holder for file callbacks */
- tr->trace_cpu.cpu = RING_BUFFER_ALL_CPUS;
- tr->trace_cpu.tr = tr;
-
tr->dir = debugfs_create_dir(name, trace_instance_dir);
if (!tr->dir)
goto out_free_tr;
@@ -6132,13 +6101,13 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer)
tr, &tracing_iter_fops);
trace_create_file("trace", 0644, d_tracer,
- (void *)&tr->trace_cpu, &tracing_fops);
+ tr, &tracing_fops);
trace_create_file("trace_pipe", 0444, d_tracer,
- (void *)&tr->trace_cpu, &tracing_pipe_fops);
+ tr, &tracing_pipe_fops);
trace_create_file("buffer_size_kb", 0644, d_tracer,
- (void *)&tr->trace_cpu, &tracing_entries_fops);
+ tr, &tracing_entries_fops);
trace_create_file("buffer_total_size_kb", 0444, d_tracer,
tr, &tracing_total_entries_fops);
@@ -6153,11 +6122,11 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer)
&trace_clock_fops);
trace_create_file("tracing_on", 0644, d_tracer,
- tr, &rb_simple_fops);
+ tr, &rb_simple_fops);
#ifdef CONFIG_TRACER_SNAPSHOT
trace_create_file("snapshot", 0644, d_tracer,
- (void *)&tr->trace_cpu, &snapshot_fops);
+ tr, &snapshot_fops);
#endif
for_each_tracing_cpu(cpu)
@@ -6451,10 +6420,6 @@ __init static int tracer_alloc_buffers(void)
global_trace.flags = TRACE_ARRAY_FL_GLOBAL;
- /* Holder for file callbacks */
- global_trace.trace_cpu.cpu = RING_BUFFER_ALL_CPUS;
- global_trace.trace_cpu.tr = &global_trace;
-
INIT_LIST_HEAD(&global_trace.systems);
INIT_LIST_HEAD(&global_trace.events);
list_add(&global_trace.list, &ftrace_trace_arrays);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index e7d643b..afaae41 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -130,19 +130,12 @@ enum trace_flag_type {
struct trace_array;
-struct trace_cpu {
- struct trace_array *tr;
- struct dentry *dir;
- int cpu;
-};
-
/*
* The CPU trace array - it consists of thousands of trace entries
* plus some other descriptor data: (for example which task started
* the trace, etc.)
*/
struct trace_array_cpu {
- struct trace_cpu trace_cpu;
atomic_t disabled;
void *buffer_page; /* ring buffer spare */
@@ -196,7 +189,6 @@ struct trace_array {
bool allocated_snapshot;
#endif
int buffer_disabled;
- struct trace_cpu trace_cpu; /* place holder */
#ifdef CONFIG_FTRACE_SYSCALLS
int sys_refcount_enter;
int sys_refcount_exit;

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