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-rw-r--r--kernel/trace/trace.c86
1 files changed, 68 insertions, 18 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 82d9b8106cd..ee9c921d7f2 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -17,7 +17,6 @@
#include <linux/writeback.h>
#include <linux/kallsyms.h>
#include <linux/seq_file.h>
-#include <linux/smp_lock.h>
#include <linux/notifier.h>
#include <linux/irqflags.h>
#include <linux/debugfs.h>
@@ -42,8 +41,6 @@
#include "trace.h"
#include "trace_output.h"
-#define TRACE_BUFFER_FLAGS (RB_FL_OVERWRITE)
-
/*
* On boot up, the ring buffer is set to the minimum size, so that
* we do not waste memory on systems that are not using tracing.
@@ -341,7 +338,7 @@ static DECLARE_WAIT_QUEUE_HEAD(trace_wait);
/* trace_flags holds trace_options default values */
unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK |
TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | TRACE_ITER_SLEEP_TIME |
- TRACE_ITER_GRAPH_TIME | TRACE_ITER_RECORD_CMD;
+ TRACE_ITER_GRAPH_TIME | TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE;
static int trace_stop_count;
static DEFINE_SPINLOCK(tracing_start_lock);
@@ -426,6 +423,7 @@ static const char *trace_options[] = {
"sleep-time",
"graph-time",
"record-cmd",
+ "overwrite",
NULL
};
@@ -781,6 +779,11 @@ __acquires(kernel_lock)
tracing_reset_online_cpus(tr);
current_trace = type;
+
+ /* If we expanded the buffers, make sure the max is expanded too */
+ if (ring_buffer_expanded && type->use_max_tr)
+ ring_buffer_resize(max_tr.buffer, trace_buf_size);
+
/* the test is responsible for initializing and enabling */
pr_info("Testing tracer %s: ", type->name);
ret = type->selftest(type, tr);
@@ -793,6 +796,10 @@ __acquires(kernel_lock)
/* Only reset on passing, to avoid touching corrupted buffers */
tracing_reset_online_cpus(tr);
+ /* Shrink the max buffer again */
+ if (ring_buffer_expanded && type->use_max_tr)
+ ring_buffer_resize(max_tr.buffer, 1);
+
printk(KERN_CONT "PASSED\n");
}
#endif
@@ -1103,7 +1110,7 @@ tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
entry->preempt_count = pc & 0xff;
entry->pid = (tsk) ? tsk->pid : 0;
- entry->lock_depth = (tsk) ? tsk->lock_depth : 0;
+ entry->padding = 0;
entry->flags =
#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
(irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
@@ -1284,6 +1291,8 @@ void trace_dump_stack(void)
__ftrace_trace_stack(global_trace.buffer, flags, 3, preempt_count());
}
+static DEFINE_PER_CPU(int, user_stack_count);
+
void
ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
{
@@ -1302,10 +1311,20 @@ ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
if (unlikely(in_nmi()))
return;
+ /*
+ * prevent recursion, since the user stack tracing may
+ * trigger other kernel events.
+ */
+ preempt_disable();
+ if (__this_cpu_read(user_stack_count))
+ goto out;
+
+ __this_cpu_inc(user_stack_count);
+
event = trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
sizeof(*entry), flags, pc);
if (!event)
- return;
+ goto out_drop_count;
entry = ring_buffer_event_data(event);
entry->tgid = current->tgid;
@@ -1319,6 +1338,11 @@ ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
save_stack_trace_user(&trace);
if (!filter_check_discard(call, entry, buffer, event))
ring_buffer_unlock_commit(buffer, event);
+
+ out_drop_count:
+ __this_cpu_dec(user_stack_count);
+ out:
+ preempt_enable();
}
#ifdef UNUSED
@@ -1733,10 +1757,9 @@ static void print_lat_help_header(struct seq_file *m)
seq_puts(m, "# | / _----=> need-resched \n");
seq_puts(m, "# || / _---=> hardirq/softirq \n");
seq_puts(m, "# ||| / _--=> preempt-depth \n");
- seq_puts(m, "# |||| /_--=> lock-depth \n");
- seq_puts(m, "# |||||/ delay \n");
- seq_puts(m, "# cmd pid |||||| time | caller \n");
- seq_puts(m, "# \\ / |||||| \\ | / \n");
+ seq_puts(m, "# |||| / delay \n");
+ seq_puts(m, "# cmd pid ||||| time | caller \n");
+ seq_puts(m, "# \\ / ||||| \\ | / \n");
}
static void print_func_help_header(struct seq_file *m)
@@ -1991,9 +2014,10 @@ enum print_line_t print_trace_line(struct trace_iterator *iter)
{
enum print_line_t ret;
- if (iter->lost_events)
- trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
- iter->cpu, iter->lost_events);
+ if (iter->lost_events &&
+ !trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
+ iter->cpu, iter->lost_events))
+ return TRACE_TYPE_PARTIAL_LINE;
if (iter->trace && iter->trace->print_line) {
ret = iter->trace->print_line(iter);
@@ -2320,11 +2344,19 @@ tracing_write_stub(struct file *filp, const char __user *ubuf,
return count;
}
+static loff_t tracing_seek(struct file *file, loff_t offset, int origin)
+{
+ if (file->f_mode & FMODE_READ)
+ return seq_lseek(file, offset, origin);
+ else
+ return 0;
+}
+
static const struct file_operations tracing_fops = {
.open = tracing_open,
.read = seq_read,
.write = tracing_write_stub,
- .llseek = seq_lseek,
+ .llseek = tracing_seek,
.release = tracing_release,
};
@@ -2505,6 +2537,9 @@ static void set_tracer_flags(unsigned int mask, int enabled)
if (mask == TRACE_ITER_RECORD_CMD)
trace_event_enable_cmd_record(enabled);
+
+ if (mask == TRACE_ITER_OVERWRITE)
+ ring_buffer_change_overwrite(global_trace.buffer, enabled);
}
static ssize_t
@@ -2686,6 +2721,10 @@ tracing_ctrl_write(struct file *filp, const char __user *ubuf,
mutex_lock(&trace_types_lock);
if (tracer_enabled ^ val) {
+
+ /* Only need to warn if this is used to change the state */
+ WARN_ONCE(1, "tracing_enabled is deprecated. Use tracing_on");
+
if (val) {
tracer_enabled = 1;
if (current_trace->start)
@@ -3192,6 +3231,14 @@ waitagain:
if (iter->seq.len >= cnt)
break;
+
+ /*
+ * Setting the full flag means we reached the trace_seq buffer
+ * size and we should leave by partial output condition above.
+ * One of the trace_seq_* functions is not used properly.
+ */
+ WARN_ONCE(iter->seq.full, "full flag set for trace type %d",
+ iter->ent->type);
}
trace_access_unlock(iter->cpu_file);
trace_event_read_unlock();
@@ -3202,7 +3249,7 @@ waitagain:
trace_seq_init(&iter->seq);
/*
- * If there was nothing to send to user, inspite of consuming trace
+ * If there was nothing to send to user, in spite of consuming trace
* entries, go back to wait for more entries.
*/
if (sret == -EBUSY)
@@ -4527,9 +4574,11 @@ void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
__init static int tracer_alloc_buffers(void)
{
int ring_buf_size;
+ enum ring_buffer_flags rb_flags;
int i;
int ret = -ENOMEM;
+
if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
goto out;
@@ -4542,12 +4591,13 @@ __init static int tracer_alloc_buffers(void)
else
ring_buf_size = 1;
+ rb_flags = trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0;
+
cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
cpumask_copy(tracing_cpumask, cpu_all_mask);
/* TODO: make the number of buffers hot pluggable with CPUS */
- global_trace.buffer = ring_buffer_alloc(ring_buf_size,
- TRACE_BUFFER_FLAGS);
+ global_trace.buffer = ring_buffer_alloc(ring_buf_size, rb_flags);
if (!global_trace.buffer) {
printk(KERN_ERR "tracer: failed to allocate ring buffer!\n");
WARN_ON(1);
@@ -4557,7 +4607,7 @@ __init static int tracer_alloc_buffers(void)
#ifdef CONFIG_TRACER_MAX_TRACE
- max_tr.buffer = ring_buffer_alloc(1, TRACE_BUFFER_FLAGS);
+ max_tr.buffer = ring_buffer_alloc(1, rb_flags);
if (!max_tr.buffer) {
printk(KERN_ERR "tracer: failed to allocate max ring buffer!\n");
WARN_ON(1);
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-04-17 14:05:12 +0000