Merge tag 'trace-v4.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
"Various fix-ups:
- comment fixes
- build fix
- better memory alloction (don't use NR_CPUS)
- configuration fix
- build warning fix
- enhanced callback parameter (to simplify users of trace hooks)
- give up on stack tracing when RCU isn't watching (it's a lost
cause)"
* tag 'trace-v4.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Have stack trace not record if RCU is not watching
tracing: Pass export pointer as argument to ->write()
ring-buffer: Remove unused function __rb_data_page_index()
tracing: make PREEMPTIRQ_EVENTS depend on TRACING
tracing: Allocate mask_str buffer dynamically
tracing: always define trace_{irq,preempt}_{enable_disable}
tracing: Fix code comments in trace.c
diff --git a/drivers/hwtracing/stm/ftrace.c b/drivers/hwtracing/stm/ftrace.c
index bd126a7..7da7564 100644
--- a/drivers/hwtracing/stm/ftrace.c
+++ b/drivers/hwtracing/stm/ftrace.c
@@ -42,9 +42,11 @@
* @len: length of the data packet
*/
static void notrace
-stm_ftrace_write(const void *buf, unsigned int len)
+stm_ftrace_write(struct trace_export *export, const void *buf, unsigned int len)
{
- stm_source_write(&stm_ftrace.data, STM_FTRACE_CHAN, buf, len);
+ struct stm_ftrace *stm = container_of(export, struct stm_ftrace, ftrace);
+
+ stm_source_write(&stm->data, STM_FTRACE_CHAN, buf, len);
}
static int stm_ftrace_link(struct stm_source_data *data)
diff --git a/include/linux/trace.h b/include/linux/trace.h
index d24991c..b95ffb2 100644
--- a/include/linux/trace.h
+++ b/include/linux/trace.h
@@ -18,7 +18,7 @@
*/
struct trace_export {
struct trace_export __rcu *next;
- void (*write)(const void *, unsigned int);
+ void (*write)(struct trace_export *, const void *, unsigned int);
};
int register_ftrace_export(struct trace_export *export);
diff --git a/include/trace/events/preemptirq.h b/include/trace/events/preemptirq.h
index f5024c5..9c4eb33 100644
--- a/include/trace/events/preemptirq.h
+++ b/include/trace/events/preemptirq.h
@@ -56,15 +56,18 @@
#include <trace/define_trace.h>
-#else /* !CONFIG_PREEMPTIRQ_EVENTS */
+#endif /* !CONFIG_PREEMPTIRQ_EVENTS */
+#if !defined(CONFIG_PREEMPTIRQ_EVENTS) || defined(CONFIG_PROVE_LOCKING)
#define trace_irq_enable(...)
#define trace_irq_disable(...)
-#define trace_preempt_enable(...)
-#define trace_preempt_disable(...)
#define trace_irq_enable_rcuidle(...)
#define trace_irq_disable_rcuidle(...)
+#endif
+
+#if !defined(CONFIG_PREEMPTIRQ_EVENTS) || !defined(CONFIG_DEBUG_PREEMPT)
+#define trace_preempt_enable(...)
+#define trace_preempt_disable(...)
#define trace_preempt_enable_rcuidle(...)
#define trace_preempt_disable_rcuidle(...)
-
#endif
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index af7dad1..904c952 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -164,6 +164,7 @@
bool "Enable trace events for preempt and irq disable/enable"
select TRACE_IRQFLAGS
depends on DEBUG_PREEMPT || !PROVE_LOCKING
+ depends on TRACING
default n
help
Enable tracing of disable and enable events for preemption and irqs.
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 91874a9..c87766c 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1799,12 +1799,6 @@
}
EXPORT_SYMBOL_GPL(ring_buffer_change_overwrite);
-static __always_inline void *
-__rb_data_page_index(struct buffer_data_page *bpage, unsigned index)
-{
- return bpage->data + index;
-}
-
static __always_inline void *__rb_page_index(struct buffer_page *bpage, unsigned index)
{
return bpage->page->data + index;
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 73e67b6..59518b8 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -362,7 +362,7 @@
}
/**
- * trace_pid_filter_add_remove - Add or remove a task from a pid_list
+ * trace_pid_filter_add_remove_task - Add or remove a task from a pid_list
* @pid_list: The list to modify
* @self: The current task for fork or NULL for exit
* @task: The task to add or remove
@@ -925,7 +925,7 @@
}
/**
- * trace_snapshot - take a snapshot of the current buffer.
+ * tracing_snapshot - take a snapshot of the current buffer.
*
* This causes a swap between the snapshot buffer and the current live
* tracing buffer. You can use this to take snapshots of the live
@@ -1004,9 +1004,9 @@
EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
/**
- * trace_snapshot_alloc - allocate and take a snapshot of the current buffer.
+ * tracing_snapshot_alloc - allocate and take a snapshot of the current buffer.
*
- * This is similar to trace_snapshot(), but it will allocate the
+ * This is similar to tracing_snapshot(), but it will allocate the
* snapshot buffer if it isn't already allocated. Use this only
* where it is safe to sleep, as the allocation may sleep.
*
@@ -1303,7 +1303,7 @@
/*
* Copy the new maximum trace into the separate maximum-trace
* structure. (this way the maximum trace is permanently saved,
- * for later retrieval via /sys/kernel/debug/tracing/latency_trace)
+ * for later retrieval via /sys/kernel/tracing/tracing_max_latency)
*/
static void
__update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
@@ -2415,7 +2415,7 @@
entry = ring_buffer_event_data(event);
size = ring_buffer_event_length(event);
- export->write(entry, size);
+ export->write(export, entry, size);
}
static DEFINE_MUTEX(ftrace_export_lock);
@@ -4178,37 +4178,30 @@
.llseek = seq_lseek,
};
-/*
- * The tracer itself will not take this lock, but still we want
- * to provide a consistent cpumask to user-space:
- */
-static DEFINE_MUTEX(tracing_cpumask_update_lock);
-
-/*
- * Temporary storage for the character representation of the
- * CPU bitmask (and one more byte for the newline):
- */
-static char mask_str[NR_CPUS + 1];
-
static ssize_t
tracing_cpumask_read(struct file *filp, char __user *ubuf,
size_t count, loff_t *ppos)
{
struct trace_array *tr = file_inode(filp)->i_private;
+ char *mask_str;
int len;
- mutex_lock(&tracing_cpumask_update_lock);
+ len = snprintf(NULL, 0, "%*pb\n",
+ cpumask_pr_args(tr->tracing_cpumask)) + 1;
+ mask_str = kmalloc(len, GFP_KERNEL);
+ if (!mask_str)
+ return -ENOMEM;
- len = snprintf(mask_str, count, "%*pb\n",
+ len = snprintf(mask_str, len, "%*pb\n",
cpumask_pr_args(tr->tracing_cpumask));
if (len >= count) {
count = -EINVAL;
goto out_err;
}
- count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1);
+ count = simple_read_from_buffer(ubuf, count, ppos, mask_str, len);
out_err:
- mutex_unlock(&tracing_cpumask_update_lock);
+ kfree(mask_str);
return count;
}
@@ -4228,8 +4221,6 @@
if (err)
goto err_unlock;
- mutex_lock(&tracing_cpumask_update_lock);
-
local_irq_disable();
arch_spin_lock(&tr->max_lock);
for_each_tracing_cpu(cpu) {
@@ -4252,8 +4243,6 @@
local_irq_enable();
cpumask_copy(tr->tracing_cpumask, tracing_cpumask_new);
-
- mutex_unlock(&tracing_cpumask_update_lock);
free_cpumask_var(tracing_cpumask_new);
return count;
diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index 734accc..3c7bfc4 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -209,6 +209,10 @@
if (__this_cpu_read(disable_stack_tracer) != 1)
goto out;
+ /* If rcu is not watching, then save stack trace can fail */
+ if (!rcu_is_watching())
+ goto out;
+
ip += MCOUNT_INSN_SIZE;
check_stack(ip, &stack);