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)
 -----BEGIN PGP SIGNATURE-----
 
 iQHIBAABCgAyFiEEPm6V/WuN2kyArTUe1a05Y9njSUkFAlozKm0UHHJvc3RlZHRA
 Z29vZG1pcy5vcmcACgkQ1a05Y9njSUmhXwv7BEY923K3Nl3qC6LeYmNyrZ4g1PsD
 nbZ+ZjU3KlMPugGbnJCJbfsS0utUp2Wd9gHT32O4BUf0/Pxjo3utXvkzRQJ3SwHT
 X7QhXROkicAKRFrPxj0BaiLexC+yJR23wGp2YUVHLO4Aa/ptN8BJvH22+eDpsCLc
 f1DWJdvdbyPBUeoHNKevjvccsUYMlnBfe1jhJ9nRWHnq1axGV3bllcd6v4T07LgK
 LO28Krp4/V3tVN9Sq6jBoGTrULf5O1xtuBDVtANeXdha1oMUTYr4TUzTuOQxFgNu
 sCIpUWTKu+PNGmU5bhlryb20C2+PveE4EMK0InVVlqrhYJ/XjXFyRaZYYkM2NAKq
 XmeHVjMfc6Wmrd/nepuaTZvGGrK2kK/pCX/XuQthKKjAU6rO5X+FfGiSGodLPIYB
 1m+QvfX8Re2IJkswm3lS68LKtG7SnjcSB9sY6PhVe6C6oP2ya2O1hthJ+TkrfNbc
 lhE5HzfCJZ9ujSjcQoUGwjrhnIezQX4KnfJZ
 =WdMQ
 -----END PGP SIGNATURE-----

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
This commit is contained in:
Linus Torvalds 2017-12-14 18:21:33 -08:00
commit 0424378781
7 changed files with 32 additions and 39 deletions

View File

@ -42,9 +42,11 @@ static struct stm_ftrace {
* @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)

View File

@ -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);

View File

@ -56,15 +56,18 @@ DEFINE_EVENT(preemptirq_template, preempt_enable,
#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

View File

@ -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.

View File

@ -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;

View File

@ -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;

View File

@ -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);