summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
Diffstat
-rw-r--r--kernel/trace/trace.h5
-rw-r--r--kernel/trace/trace_events.c221
2 files changed, 102 insertions, 124 deletions
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 3fff4ad..68cbb8e 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -177,9 +177,8 @@ struct trace_options {
};
struct trace_pid_list {
- unsigned int nr_pids;
- int order;
- pid_t *pids;
+ int pid_max;
+ unsigned long *pids;
};
/*
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 598a186..45f7cc7 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -15,7 +15,7 @@
#include <linux/kthread.h>
#include <linux/tracefs.h>
#include <linux/uaccess.h>
-#include <linux/bsearch.h>
+#include <linux/vmalloc.h>
#include <linux/module.h>
#include <linux/ctype.h>
#include <linux/sort.h>
@@ -471,23 +471,13 @@ static void ftrace_clear_events(struct trace_array *tr)
mutex_unlock(&event_mutex);
}
-static int cmp_pid(const void *key, const void *elt)
-{
- const pid_t *search_pid = key;
- const pid_t *pid = elt;
-
- if (*search_pid == *pid)
- return 0;
- if (*search_pid < *pid)
- return -1;
- return 1;
-}
+/* Shouldn't this be in a header? */
+extern int pid_max;
static bool
ignore_this_task(struct trace_pid_list *filtered_pids, struct task_struct *task)
{
- pid_t search_pid;
- pid_t *pid;
+ pid_t pid;
/*
* Return false, because if filtered_pids does not exist,
@@ -496,15 +486,16 @@ ignore_this_task(struct trace_pid_list *filtered_pids, struct task_struct *task)
if (!filtered_pids)
return false;
- search_pid = task->pid;
+ pid = task->pid;
- pid = bsearch(&search_pid, filtered_pids->pids,
- filtered_pids->nr_pids, sizeof(pid_t),
- cmp_pid);
- if (!pid)
+ /*
+ * If pid_max changed after filtered_pids was created, we
+ * by default ignore all pids greater than the previous pid_max.
+ */
+ if (task->pid >= filtered_pids->pid_max)
return true;
- return false;
+ return !test_bit(task->pid, filtered_pids->pids);
}
static void
@@ -602,7 +593,7 @@ static void __ftrace_clear_event_pids(struct trace_array *tr)
/* Wait till all users are no longer using pid filtering */
synchronize_sched();
- free_pages((unsigned long)pid_list->pids, pid_list->order);
+ vfree(pid_list->pids);
kfree(pid_list);
}
@@ -946,11 +937,32 @@ static void t_stop(struct seq_file *m, void *p)
mutex_unlock(&event_mutex);
}
+static void *
+p_next(struct seq_file *m, void *v, loff_t *pos)
+{
+ struct trace_array *tr = m->private;
+ struct trace_pid_list *pid_list = rcu_dereference_sched(tr->filtered_pids);
+ unsigned long pid = (unsigned long)v;
+
+ (*pos)++;
+
+ /* pid already is +1 of the actual prevous bit */
+ pid = find_next_bit(pid_list->pids, pid_list->pid_max, pid);
+
+ /* Return pid + 1 to allow zero to be represented */
+ if (pid < pid_list->pid_max)
+ return (void *)(pid + 1);
+
+ return NULL;
+}
+
static void *p_start(struct seq_file *m, loff_t *pos)
__acquires(RCU)
{
struct trace_pid_list *pid_list;
struct trace_array *tr = m->private;
+ unsigned long pid;
+ loff_t l = 0;
/*
* Grab the mutex, to keep calls to p_next() having the same
@@ -963,10 +975,18 @@ static void *p_start(struct seq_file *m, loff_t *pos)
pid_list = rcu_dereference_sched(tr->filtered_pids);
- if (!pid_list || *pos >= pid_list->nr_pids)
+ if (!pid_list)
+ return NULL;
+
+ pid = find_first_bit(pid_list->pids, pid_list->pid_max);
+ if (pid >= pid_list->pid_max)
return NULL;
- return (void *)&pid_list->pids[*pos];
+ /* Return pid + 1 so that zero can be the exit value */
+ for (pid++; pid && l < *pos;
+ pid = (unsigned long)p_next(m, (void *)pid, &l))
+ ;
+ return (void *)pid;
}
static void p_stop(struct seq_file *m, void *p)
@@ -976,25 +996,11 @@ static void p_stop(struct seq_file *m, void *p)
mutex_unlock(&event_mutex);
}
-static void *
-p_next(struct seq_file *m, void *v, loff_t *pos)
-{
- struct trace_array *tr = m->private;
- struct trace_pid_list *pid_list = rcu_dereference_sched(tr->filtered_pids);
-
- (*pos)++;
-
- if (*pos >= pid_list->nr_pids)
- return NULL;
-
- return (void *)&pid_list->pids[*pos];
-}
-
static int p_show(struct seq_file *m, void *v)
{
- pid_t *pid = v;
+ unsigned long pid = (unsigned long)v - 1;
- seq_printf(m, "%d\n", *pid);
+ seq_printf(m, "%lu\n", pid);
return 0;
}
@@ -1543,11 +1549,6 @@ show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
return r;
}
-static int max_pids(struct trace_pid_list *pid_list)
-{
- return (PAGE_SIZE << pid_list->order) / sizeof(pid_t);
-}
-
static void ignore_task_cpu(void *data)
{
struct trace_array *tr = data;
@@ -1571,7 +1572,7 @@ ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
struct seq_file *m = filp->private_data;
struct trace_array *tr = m->private;
struct trace_pid_list *filtered_pids = NULL;
- struct trace_pid_list *pid_list = NULL;
+ struct trace_pid_list *pid_list;
struct trace_event_file *file;
struct trace_parser parser;
unsigned long val;
@@ -1579,7 +1580,7 @@ ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
ssize_t read = 0;
ssize_t ret = 0;
pid_t pid;
- int i;
+ int nr_pids = 0;
if (!cnt)
return 0;
@@ -1592,10 +1593,43 @@ ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
return -ENOMEM;
mutex_lock(&event_mutex);
+ filtered_pids = rcu_dereference_protected(tr->filtered_pids,
+ lockdep_is_held(&event_mutex));
+
/*
- * Load as many pids into the array before doing a
- * swap from the tr->filtered_pids to the new list.
+ * Always recreate a new array. The write is an all or nothing
+ * operation. Always create a new array when adding new pids by
+ * the user. If the operation fails, then the current list is
+ * not modified.
*/
+ pid_list = kmalloc(sizeof(*pid_list), GFP_KERNEL);
+ if (!pid_list) {
+ read = -ENOMEM;
+ goto out;
+ }
+ pid_list->pid_max = READ_ONCE(pid_max);
+ /* Only truncating will shrink pid_max */
+ if (filtered_pids && filtered_pids->pid_max > pid_list->pid_max)
+ pid_list->pid_max = filtered_pids->pid_max;
+ pid_list->pids = vzalloc((pid_list->pid_max + 7) >> 3);
+ if (!pid_list->pids) {
+ kfree(pid_list);
+ read = -ENOMEM;
+ goto out;
+ }
+ if (filtered_pids) {
+ /* copy the current bits to the new max */
+ pid = find_first_bit(filtered_pids->pids,
+ filtered_pids->pid_max);
+ while (pid < filtered_pids->pid_max) {
+ set_bit(pid, pid_list->pids);
+ pid = find_next_bit(filtered_pids->pids,
+ filtered_pids->pid_max,
+ pid + 1);
+ nr_pids++;
+ }
+ }
+
while (cnt > 0) {
this_pos = 0;
@@ -1613,92 +1647,35 @@ ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
ret = -EINVAL;
if (kstrtoul(parser.buffer, 0, &val))
break;
- if (val > INT_MAX)
+ if (val >= pid_list->pid_max)
break;
pid = (pid_t)val;
- ret = -ENOMEM;
- if (!pid_list) {
- pid_list = kmalloc(sizeof(*pid_list), GFP_KERNEL);
- if (!pid_list)
- break;
-
- filtered_pids = rcu_dereference_protected(tr->filtered_pids,
- lockdep_is_held(&event_mutex));
- if (filtered_pids)
- pid_list->order = filtered_pids->order;
- else
- pid_list->order = 0;
-
- pid_list->pids = (void *)__get_free_pages(GFP_KERNEL,
- pid_list->order);
- if (!pid_list->pids)
- break;
-
- if (filtered_pids) {
- pid_list->nr_pids = filtered_pids->nr_pids;
- memcpy(pid_list->pids, filtered_pids->pids,
- pid_list->nr_pids * sizeof(pid_t));
- } else
- pid_list->nr_pids = 0;
- }
-
- if (pid_list->nr_pids >= max_pids(pid_list)) {
- pid_t *pid_page;
-
- pid_page = (void *)__get_free_pages(GFP_KERNEL,
- pid_list->order + 1);
- if (!pid_page)
- break;
- memcpy(pid_page, pid_list->pids,
- pid_list->nr_pids * sizeof(pid_t));
- free_pages((unsigned long)pid_list->pids, pid_list->order);
-
- pid_list->order++;
- pid_list->pids = pid_page;
- }
+ set_bit(pid, pid_list->pids);
+ nr_pids++;
- pid_list->pids[pid_list->nr_pids++] = pid;
trace_parser_clear(&parser);
ret = 0;
}
trace_parser_put(&parser);
if (ret < 0) {
- if (pid_list)
- free_pages((unsigned long)pid_list->pids, pid_list->order);
+ vfree(pid_list->pids);
kfree(pid_list);
- mutex_unlock(&event_mutex);
- return ret;
- }
-
- if (!pid_list) {
- mutex_unlock(&event_mutex);
- return ret;
+ read = ret;
+ goto out;
}
- sort(pid_list->pids, pid_list->nr_pids, sizeof(pid_t), cmp_pid, NULL);
-
- /* Remove duplicates */
- for (i = 1; i < pid_list->nr_pids; i++) {
- int start = i;
-
- while (i < pid_list->nr_pids &&
- pid_list->pids[i - 1] == pid_list->pids[i])
- i++;
-
- if (start != i) {
- if (i < pid_list->nr_pids) {
- memmove(&pid_list->pids[start], &pid_list->pids[i],
- (pid_list->nr_pids - i) * sizeof(pid_t));
- pid_list->nr_pids -= i - start;
- i = start;
- } else
- pid_list->nr_pids = start;
- }
+ if (!nr_pids) {
+ /* Cleared the list of pids */
+ vfree(pid_list->pids);
+ kfree(pid_list);
+ read = ret;
+ if (!filtered_pids)
+ goto out;
+ pid_list = NULL;
}
-
rcu_assign_pointer(tr->filtered_pids, pid_list);
list_for_each_entry(file, &tr->events, list) {
@@ -1708,7 +1685,7 @@ ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
if (filtered_pids) {
synchronize_sched();
- free_pages((unsigned long)filtered_pids->pids, filtered_pids->order);
+ vfree(filtered_pids->pids);
kfree(filtered_pids);
} else {
/*
@@ -1745,10 +1722,12 @@ ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
*/
on_each_cpu(ignore_task_cpu, tr, 1);
+ out:
mutex_unlock(&event_mutex);
ret = read;
- *ppos += read;
+ if (read > 0)
+ *ppos += read;
return ret;
}
generated by cgit v0.10.2 at 2024-07-28 13:10:52 (GMT)