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authorLinus Torvalds <torvalds@linux-foundation.org>2017-12-15 05:21:33 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2017-12-15 05:21:33 +0300
commit04243787812cabb57726e50d8288a3dcacf54ad2 (patch)
treea6b3488138b03a3378dfcb1360319b274ba74f55 /kernel
parentc4f988ee51ed896f5f709ba611a18485a2204ace (diff)
parentb00d607bb188e187c7b60074d2fa91a6f1985029 (diff)
downloadlinux-04243787812cabb57726e50d8288a3dcacf54ad2.tar.xz
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
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/Kconfig1
-rw-r--r--kernel/trace/ring_buffer.c6
-rw-r--r--kernel/trace/trace.c41
-rw-r--r--kernel/trace/trace_stack.c4
4 files changed, 20 insertions, 32 deletions
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index af7dad126c13..904c952ac383 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -164,6 +164,7 @@ config PREEMPTIRQ_EVENTS
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 91874a95060d..c87766c1c204 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1799,12 +1799,6 @@ void ring_buffer_change_overwrite(struct ring_buffer *buffer, int val)
}
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 73e67b68c53b..59518b8126d0 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -362,7 +362,7 @@ trace_ignore_this_task(struct trace_pid_list *filtered_pids, struct task_struct
}
/**
- * 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 @@ static void tracing_snapshot_instance(struct trace_array *tr)
}
/**
- * 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 @@ int tracing_alloc_snapshot(void)
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 @@ unsigned long __read_mostly tracing_thresh;
/*
* 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 @@ trace_process_export(struct trace_export *export,
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 @@ static const struct file_operations show_traces_fops = {
.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 @@ tracing_cpumask_write(struct file *filp, const char __user *ubuf,
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 @@ tracing_cpumask_write(struct file *filp, const char __user *ubuf,
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 734accc02418..3c7bfc4bf5e9 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -209,6 +209,10 @@ stack_trace_call(unsigned long ip, unsigned long parent_ip,
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);