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ksym_tracer: Remove trace_stat

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trace_stat is problematic. Don't use it, use seqfile instead.

This fixes a race that reading the stat file is not protected by
any lock, which can lead to use after free.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4B3AF203.40200@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Li Zefan 2009-12-30 14:24:03 +08:00 committed by Ingo Molnar
parent e6d9491bf8
commit 53ab668064
1 changed files with 56 additions and 83 deletions
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139
kernel/trace/trace_ksym.c
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@ -26,7 +26,6 @@
#include <linux/fs.h>
#include "trace_output.h"
#include "trace_stat.h"
#include "trace.h"
#include <linux/hw_breakpoint.h>
@ -444,103 +443,77 @@ struct tracer ksym_tracer __read_mostly =
.print_line = ksym_trace_output
};
__init static int init_ksym_trace(void)
{
struct dentry *d_tracer;
struct dentry *entry;
d_tracer = tracing_init_dentry();
ksym_filter_entry_count = 0;
entry = debugfs_create_file("ksym_trace_filter", 0644, d_tracer,
NULL, &ksym_tracing_fops);
if (!entry)
pr_warning("Could not create debugfs "
"'ksym_trace_filter' file\n");
return register_tracer(&ksym_tracer);
}
device_initcall(init_ksym_trace);
#ifdef CONFIG_PROFILE_KSYM_TRACER
static int ksym_tracer_stat_headers(struct seq_file *m)
static int ksym_profile_show(struct seq_file *m, void *v)
{
seq_puts(m, " Access Type ");
seq_puts(m, " Symbol Counter\n");
seq_puts(m, " ----------- ");
seq_puts(m, " ------ -------\n");
return 0;
}
static int ksym_tracer_stat_show(struct seq_file *m, void *v)
{
struct hlist_node *stat = v;
struct hlist_node *node;
struct trace_ksym *entry;
int access_type = 0;
char fn_name[KSYM_NAME_LEN];
entry = hlist_entry(stat, struct trace_ksym, ksym_hlist);
seq_puts(m, " Access Type ");
seq_puts(m, " Symbol Counter\n");
seq_puts(m, " ----------- ");
seq_puts(m, " ------ -------\n");
access_type = entry->attr.bp_type;
rcu_read_lock();
hlist_for_each_entry_rcu(entry, node, &ksym_filter_head, ksym_hlist) {
switch (access_type) {
case HW_BREAKPOINT_R:
seq_puts(m, " R ");
break;
case HW_BREAKPOINT_W:
seq_puts(m, " W ");
break;
case HW_BREAKPOINT_R | HW_BREAKPOINT_W:
seq_puts(m, " RW ");
break;
default:
seq_puts(m, " NA ");
access_type = entry->attr.bp_type;
switch (access_type) {
case HW_BREAKPOINT_R:
seq_puts(m, " R ");
break;
case HW_BREAKPOINT_W:
seq_puts(m, " W ");
break;
case HW_BREAKPOINT_R | HW_BREAKPOINT_W:
seq_puts(m, " RW ");
break;
default:
seq_puts(m, " NA ");
}
if (lookup_symbol_name(entry->attr.bp_addr, fn_name) >= 0)
seq_printf(m, " %-36s", fn_name);
else
seq_printf(m, " %-36s", "<NA>");
seq_printf(m, " %15llu\n",
(unsigned long long)atomic64_read(&entry->counter));
}
if (lookup_symbol_name(entry->attr.bp_addr, fn_name) >= 0)
seq_printf(m, " %-36s", fn_name);
else
seq_printf(m, " %-36s", "<NA>");
seq_printf(m, " %15llu\n",
(unsigned long long)atomic64_read(&entry->counter));
rcu_read_unlock();
return 0;
}
static void *ksym_tracer_stat_start(struct tracer_stat *trace)
static int ksym_profile_open(struct inode *node, struct file *file)
{
return ksym_filter_head.first;
return single_open(file, ksym_profile_show, NULL);
}
static void *
ksym_tracer_stat_next(void *v, int idx)
{
struct hlist_node *stat = v;
return stat->next;
}
static struct tracer_stat ksym_tracer_stats = {
.name = "ksym_tracer",
.stat_start = ksym_tracer_stat_start,
.stat_next = ksym_tracer_stat_next,
.stat_headers = ksym_tracer_stat_headers,
.stat_show = ksym_tracer_stat_show
static const struct file_operations ksym_profile_fops = {
.open = ksym_profile_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
__init static int ksym_tracer_stat_init(void)
{
int ret;
ret = register_stat_tracer(&ksym_tracer_stats);
if (ret) {
printk(KERN_WARNING "Warning: could not register "
"ksym tracer stats\n");
return 1;
}
return 0;
}
fs_initcall(ksym_tracer_stat_init);
#endif /* CONFIG_PROFILE_KSYM_TRACER */
__init static int init_ksym_trace(void)
{
struct dentry *d_tracer;
d_tracer = tracing_init_dentry();
trace_create_file("ksym_trace_filter", 0644, d_tracer,
NULL, &ksym_tracing_fops);
#ifdef CONFIG_PROFILE_KSYM_TRACER
trace_create_file("ksym_profile", 0444, d_tracer,
NULL, &ksym_profile_fops);
#endif
return register_tracer(&ksym_tracer);
}
device_initcall(init_ksym_trace);