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Subject[GIT PULL] tracing: Fixes for v6.1

Linus,

Tracing fixes:

- Fix polling to block on watermark like the reads do, as user space
applications get confused when the select says read is available, and then
the read blocks.

- Fix accounting of ring buffer dropped pages as it is what is used to
determine if the buffer is empty or not.

- Fix memory leak in tracing_read_pipe()

- Fix struct trace_array warning about being declared in parameters

- Fix accounting of ftrace pages used in output at start up.

- Fix allocation of dyn_ftrace pages by subtracting one from order instead of
diving it by 2

- Static analyzer found a case were a pointer being used outside of a NULL
check. (rb_head_page_deactivate())

- Fix possible NULL pointer dereference if kstrdup() fails in ftrace_add_mod()

- Fix memory leak in test_gen_synth_cmd() and test_empty_synth_event()

- Fix bad pointer dereference in register_synth_event() on error path.

- Remove unused __bad_type_size() method

- Fix possible NULL pointer dereference of entry in list 'tr->err_log'

- Fix NULL pointer deference race if eprobe is called before the event setup


Please pull the latest trace-v6.1-rc5 tree, which can be found at:


git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git
trace-v6.1-rc5

Tag SHA1: 841b9a46b1091224f5a111bd248ee55309bd38ce
Head SHA1: 94eedf3dded5fb472ce97bfaf3ac1c6c29c35d26


Aashish Sharma (1):
tracing: Fix warning on variable 'struct trace_array'

Daniil Tatianin (1):
ring_buffer: Do not deactivate non-existant pages

Qiujun Huang (1):
tracing: Remove unused __bad_type_size() method

Shang XiaoJing (2):
tracing: Fix memory leak in test_gen_synth_cmd() and test_empty_synth_event()
tracing: Fix wild-memory-access in register_synth_event()

Steven Rostedt (Google) (3):
tracing/ring-buffer: Have polling block on watermark
ring-buffer: Include dropped pages in counting dirty patches
tracing: Fix race where eprobes can be called before the event

Wang Wensheng (2):
ftrace: Fix the possible incorrect kernel message
ftrace: Optimize the allocation for mcount entries

Wang Yufen (1):
tracing: Fix memory leak in tracing_read_pipe()

Xiu Jianfeng (1):
ftrace: Fix null pointer dereference in ftrace_add_mod()

Zheng Yejian (1):
tracing: Fix potential null-pointer-access of entry in list 'tr->err_log'

----
include/linux/ring_buffer.h | 2 +-
include/linux/trace.h | 4 +--
kernel/trace/ftrace.c | 5 +--
kernel/trace/ring_buffer.c | 71 ++++++++++++++++++++++++++-----------
kernel/trace/synth_event_gen_test.c | 16 ++++-----
kernel/trace/trace.c | 12 ++++---
kernel/trace/trace_eprobe.c | 3 ++
kernel/trace/trace_events_synth.c | 5 ++-
kernel/trace/trace_syscalls.c | 2 --
9 files changed, 74 insertions(+), 46 deletions(-)
---------------------------
diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h
index 2504df9a0453..3c7d295746f6 100644
--- a/include/linux/ring_buffer.h
+++ b/include/linux/ring_buffer.h
@@ -100,7 +100,7 @@ __ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *k

int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full);
__poll_t ring_buffer_poll_wait(struct trace_buffer *buffer, int cpu,
- struct file *filp, poll_table *poll_table);
+ struct file *filp, poll_table *poll_table, int full);
void ring_buffer_wake_waiters(struct trace_buffer *buffer, int cpu);

#define RING_BUFFER_ALL_CPUS -1
diff --git a/include/linux/trace.h b/include/linux/trace.h
index b5e16e438448..80ffda871749 100644
--- a/include/linux/trace.h
+++ b/include/linux/trace.h
@@ -26,13 +26,13 @@ struct trace_export {
int flags;
};

+struct trace_array;
+
#ifdef CONFIG_TRACING

int register_ftrace_export(struct trace_export *export);
int unregister_ftrace_export(struct trace_export *export);

-struct trace_array;
-
void trace_printk_init_buffers(void);
__printf(3, 4)
int trace_array_printk(struct trace_array *tr, unsigned long ip,
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 7dc023641bf1..33236241f236 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1289,6 +1289,7 @@ static int ftrace_add_mod(struct trace_array *tr,
if (!ftrace_mod)
return -ENOMEM;

+ INIT_LIST_HEAD(&ftrace_mod->list);
ftrace_mod->func = kstrdup(func, GFP_KERNEL);
ftrace_mod->module = kstrdup(module, GFP_KERNEL);
ftrace_mod->enable = enable;
@@ -3190,7 +3191,7 @@ static int ftrace_allocate_records(struct ftrace_page *pg, int count)
/* if we can't allocate this size, try something smaller */
if (!order)
return -ENOMEM;
- order >>= 1;
+ order--;
goto again;
}

@@ -7391,7 +7392,7 @@ void __init ftrace_init(void)
}

pr_info("ftrace: allocating %ld entries in %ld pages\n",
- count, count / ENTRIES_PER_PAGE + 1);
+ count, DIV_ROUND_UP(count, ENTRIES_PER_PAGE));

ret = ftrace_process_locs(NULL,
__start_mcount_loc,
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 9712083832f4..b21bf14bae9b 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -519,6 +519,7 @@ struct ring_buffer_per_cpu {
local_t committing;
local_t commits;
local_t pages_touched;
+ local_t pages_lost;
local_t pages_read;
long last_pages_touch;
size_t shortest_full;
@@ -894,10 +895,18 @@ size_t ring_buffer_nr_pages(struct trace_buffer *buffer, int cpu)
size_t ring_buffer_nr_dirty_pages(struct trace_buffer *buffer, int cpu)
{
size_t read;
+ size_t lost;
size_t cnt;

read = local_read(&buffer->buffers[cpu]->pages_read);
+ lost = local_read(&buffer->buffers[cpu]->pages_lost);
cnt = local_read(&buffer->buffers[cpu]->pages_touched);
+
+ if (WARN_ON_ONCE(cnt < lost))
+ return 0;
+
+ cnt -= lost;
+
/* The reader can read an empty page, but not more than that */
if (cnt < read) {
WARN_ON_ONCE(read > cnt + 1);
@@ -907,6 +916,21 @@ size_t ring_buffer_nr_dirty_pages(struct trace_buffer *buffer, int cpu)
return cnt - read;
}

+static __always_inline bool full_hit(struct trace_buffer *buffer, int cpu, int full)
+{
+ struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu];
+ size_t nr_pages;
+ size_t dirty;
+
+ nr_pages = cpu_buffer->nr_pages;
+ if (!nr_pages || !full)
+ return true;
+
+ dirty = ring_buffer_nr_dirty_pages(buffer, cpu);
+
+ return (dirty * 100) > (full * nr_pages);
+}
+
/*
* rb_wake_up_waiters - wake up tasks waiting for ring buffer input
*
@@ -1046,22 +1070,20 @@ int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full)
!ring_buffer_empty_cpu(buffer, cpu)) {
unsigned long flags;
bool pagebusy;
- size_t nr_pages;
- size_t dirty;
+ bool done;

if (!full)
break;

raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
pagebusy = cpu_buffer->reader_page == cpu_buffer->commit_page;
- nr_pages = cpu_buffer->nr_pages;
- dirty = ring_buffer_nr_dirty_pages(buffer, cpu);
+ done = !pagebusy && full_hit(buffer, cpu, full);
+
if (!cpu_buffer->shortest_full ||
cpu_buffer->shortest_full > full)
cpu_buffer->shortest_full = full;
raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
- if (!pagebusy &&
- (!nr_pages || (dirty * 100) > full * nr_pages))
+ if (done)
break;
}

@@ -1087,6 +1109,7 @@ int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full)
* @cpu: the cpu buffer to wait on
* @filp: the file descriptor
* @poll_table: The poll descriptor
+ * @full: wait until the percentage of pages are available, if @cpu != RING_BUFFER_ALL_CPUS
*
* If @cpu == RING_BUFFER_ALL_CPUS then the task will wake up as soon
* as data is added to any of the @buffer's cpu buffers. Otherwise
@@ -1096,14 +1119,15 @@ int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full)
* zero otherwise.
*/
__poll_t ring_buffer_poll_wait(struct trace_buffer *buffer, int cpu,
- struct file *filp, poll_table *poll_table)
+ struct file *filp, poll_table *poll_table, int full)
{
struct ring_buffer_per_cpu *cpu_buffer;
struct rb_irq_work *work;

- if (cpu == RING_BUFFER_ALL_CPUS)
+ if (cpu == RING_BUFFER_ALL_CPUS) {
work = &buffer->irq_work;
- else {
+ full = 0;
+ } else {
if (!cpumask_test_cpu(cpu, buffer->cpumask))
return -EINVAL;

@@ -1111,8 +1135,14 @@ __poll_t ring_buffer_poll_wait(struct trace_buffer *buffer, int cpu,
work = &cpu_buffer->irq_work;
}

- poll_wait(filp, &work->waiters, poll_table);
- work->waiters_pending = true;
+ if (full) {
+ poll_wait(filp, &work->full_waiters, poll_table);
+ work->full_waiters_pending = true;
+ } else {
+ poll_wait(filp, &work->waiters, poll_table);
+ work->waiters_pending = true;
+ }
+
/*
* There's a tight race between setting the waiters_pending and
* checking if the ring buffer is empty. Once the waiters_pending bit
@@ -1128,6 +1158,9 @@ __poll_t ring_buffer_poll_wait(struct trace_buffer *buffer, int cpu,
*/
smp_mb();

+ if (full)
+ return full_hit(buffer, cpu, full) ? EPOLLIN | EPOLLRDNORM : 0;
+
if ((cpu == RING_BUFFER_ALL_CPUS && !ring_buffer_empty(buffer)) ||
(cpu != RING_BUFFER_ALL_CPUS && !ring_buffer_empty_cpu(buffer, cpu)))
return EPOLLIN | EPOLLRDNORM;
@@ -1769,9 +1802,9 @@ static void rb_free_cpu_buffer(struct ring_buffer_per_cpu *cpu_buffer)

free_buffer_page(cpu_buffer->reader_page);

- rb_head_page_deactivate(cpu_buffer);
-
if (head) {
+ rb_head_page_deactivate(cpu_buffer);
+
list_for_each_entry_safe(bpage, tmp, head, list) {
list_del_init(&bpage->list);
free_buffer_page(bpage);
@@ -2007,6 +2040,7 @@ rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned long nr_pages)
*/
local_add(page_entries, &cpu_buffer->overrun);
local_sub(BUF_PAGE_SIZE, &cpu_buffer->entries_bytes);
+ local_inc(&cpu_buffer->pages_lost);
}

/*
@@ -2491,6 +2525,7 @@ rb_handle_head_page(struct ring_buffer_per_cpu *cpu_buffer,
*/
local_add(entries, &cpu_buffer->overrun);
local_sub(BUF_PAGE_SIZE, &cpu_buffer->entries_bytes);
+ local_inc(&cpu_buffer->pages_lost);

/*
* The entries will be zeroed out when we move the
@@ -3155,10 +3190,6 @@ static void rb_commit(struct ring_buffer_per_cpu *cpu_buffer,
static __always_inline void
rb_wakeups(struct trace_buffer *buffer, struct ring_buffer_per_cpu *cpu_buffer)
{
- size_t nr_pages;
- size_t dirty;
- size_t full;
-
if (buffer->irq_work.waiters_pending) {
buffer->irq_work.waiters_pending = false;
/* irq_work_queue() supplies it's own memory barriers */
@@ -3182,10 +3213,7 @@ rb_wakeups(struct trace_buffer *buffer, struct ring_buffer_per_cpu *cpu_buffer)

cpu_buffer->last_pages_touch = local_read(&cpu_buffer->pages_touched);

- full = cpu_buffer->shortest_full;
- nr_pages = cpu_buffer->nr_pages;
- dirty = ring_buffer_nr_dirty_pages(buffer, cpu_buffer->cpu);
- if (full && nr_pages && (dirty * 100) <= full * nr_pages)
+ if (!full_hit(buffer, cpu_buffer->cpu, cpu_buffer->shortest_full))
return;

cpu_buffer->irq_work.wakeup_full = true;
@@ -5248,6 +5276,7 @@ rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer)
local_set(&cpu_buffer->committing, 0);
local_set(&cpu_buffer->commits, 0);
local_set(&cpu_buffer->pages_touched, 0);
+ local_set(&cpu_buffer->pages_lost, 0);
local_set(&cpu_buffer->pages_read, 0);
cpu_buffer->last_pages_touch = 0;
cpu_buffer->shortest_full = 0;
diff --git a/kernel/trace/synth_event_gen_test.c b/kernel/trace/synth_event_gen_test.c
index 0b15e975d2c2..8d77526892f4 100644
--- a/kernel/trace/synth_event_gen_test.c
+++ b/kernel/trace/synth_event_gen_test.c
@@ -120,15 +120,13 @@ static int __init test_gen_synth_cmd(void)

/* Now generate a gen_synth_test event */
ret = synth_event_trace_array(gen_synth_test, vals, ARRAY_SIZE(vals));
- out:
+ free:
+ kfree(buf);
return ret;
delete:
/* We got an error after creating the event, delete it */
synth_event_delete("gen_synth_test");
- free:
- kfree(buf);
-
- goto out;
+ goto free;
}

/*
@@ -227,15 +225,13 @@ static int __init test_empty_synth_event(void)

/* Now trace an empty_synth_test event */
ret = synth_event_trace_array(empty_synth_test, vals, ARRAY_SIZE(vals));
- out:
+ free:
+ kfree(buf);
return ret;
delete:
/* We got an error after creating the event, delete it */
synth_event_delete("empty_synth_test");
- free:
- kfree(buf);
-
- goto out;
+ goto free;
}

static struct synth_field_desc create_synth_test_fields[] = {
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 47a44b055a1d..a7fe0e115272 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -6657,6 +6657,7 @@ static int tracing_release_pipe(struct inode *inode, struct file *file)
mutex_unlock(&trace_types_lock);

free_cpumask_var(iter->started);
+ kfree(iter->fmt);
mutex_destroy(&iter->mutex);
kfree(iter);

@@ -6681,7 +6682,7 @@ trace_poll(struct trace_iterator *iter, struct file *filp, poll_table *poll_tabl
return EPOLLIN | EPOLLRDNORM;
else
return ring_buffer_poll_wait(iter->array_buffer->buffer, iter->cpu_file,
- filp, poll_table);
+ filp, poll_table, iter->tr->buffer_percent);
}

static __poll_t
@@ -7802,6 +7803,7 @@ static struct tracing_log_err *get_tracing_log_err(struct trace_array *tr,
int len)
{
struct tracing_log_err *err;
+ char *cmd;

if (tr->n_err_log_entries < TRACING_LOG_ERRS_MAX) {
err = alloc_tracing_log_err(len);
@@ -7810,12 +7812,12 @@ static struct tracing_log_err *get_tracing_log_err(struct trace_array *tr,

return err;
}
-
+ cmd = kzalloc(len, GFP_KERNEL);
+ if (!cmd)
+ return ERR_PTR(-ENOMEM);
err = list_first_entry(&tr->err_log, struct tracing_log_err, list);
kfree(err->cmd);
- err->cmd = kzalloc(len, GFP_KERNEL);
- if (!err->cmd)
- return ERR_PTR(-ENOMEM);
+ err->cmd = cmd;
list_del(&err->list);

return err;
diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
index 5dd0617e5df6..9cda9a38422c 100644
--- a/kernel/trace/trace_eprobe.c
+++ b/kernel/trace/trace_eprobe.c
@@ -563,6 +563,9 @@ static void eprobe_trigger_func(struct event_trigger_data *data,
{
struct eprobe_data *edata = data->private_data;

+ if (unlikely(!rec))
+ return;
+
__eprobe_trace_func(edata, rec);
}

diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
index e310052dc83c..29fbfb27c2b2 100644
--- a/kernel/trace/trace_events_synth.c
+++ b/kernel/trace/trace_events_synth.c
@@ -828,10 +828,9 @@ static int register_synth_event(struct synth_event *event)
}

ret = set_synth_event_print_fmt(call);
- if (ret < 0) {
+ /* unregister_trace_event() will be called inside */
+ if (ret < 0)
trace_remove_event_call(call);
- goto err;
- }
out:
return ret;
err:
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index b69e207012c9..942ddbdace4a 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -201,8 +201,6 @@ print_syscall_exit(struct trace_iterator *iter, int flags,
return trace_handle_return(s);
}

-extern char *__bad_type_size(void);
-
#define SYSCALL_FIELD(_type, _name) { \
.type = #_type, .name = #_name, \
.size = sizeof(_type), .align = __alignof__(_type), \
\
 
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