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Commit 558df6c8 authored by Li Zefan's avatar Li Zefan Committed by Ingo Molnar
Browse files

ksym_tracer: Fix memory leak 



- When remove a filter, we leak entry->ksym_hbp->info.name.

- With CONFIG_FTRAC_SELFTEST enabled, we leak ->info.name:
    # echo ksym_tracer > current_tracer
    # echo 'ksym_selftest_dummy:rw-' > ksym_trace_filter
    # echo nop > current_tracer

Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
Acked-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Cc: "K.Prasad" <prasad@linux.vnet.ibm.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <4A52E328.8010200@cn.fujitsu.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 0d109c8f

kernel/trace/trace_ksym.c

+27 −34
Original line number Diff line number Diff line
@@ -179,7 +179,7 @@ static int parse_ksym_trace_str(char *input_string, char **ksymname, 
int process_new_ksym_entry(char *ksymname, int op, unsigned long addr)

{

	struct trace_ksym *entry;

	int ret;

	int ret = -ENOMEM;



	if (ksym_filter_entry_count >= KSYM_TRACER_MAX) {

		printk(KERN_ERR "ksym_tracer: Maximum limit:(%d) reached. No"
@@ -193,12 +193,13 @@ int process_new_ksym_entry(char *ksymname, int op, unsigned long addr) 
		return -ENOMEM;



	entry->ksym_hbp = kzalloc(sizeof(struct hw_breakpoint), GFP_KERNEL);

	if (!entry->ksym_hbp) {

		kfree(entry);

		return -ENOMEM;

	}

	if (!entry->ksym_hbp)

		goto err;



	entry->ksym_hbp->info.name = kstrdup(ksymname, GFP_KERNEL);

	if (!entry->ksym_hbp->info.name)

		goto err;



	entry->ksym_hbp->info.name = ksymname;

	entry->ksym_hbp->info.type = op;

	entry->ksym_addr = entry->ksym_hbp->info.address = addr;

#ifdef CONFIG_X86
@@ -210,14 +211,18 @@ int process_new_ksym_entry(char *ksymname, int op, unsigned long addr) 
	if (ret < 0) {

		printk(KERN_INFO "ksym_tracer request failed. Try again"

					" later!!\n");

		kfree(entry->ksym_hbp);

		kfree(entry);

		return -EAGAIN;

		ret = -EAGAIN;

		goto err;

	}

	hlist_add_head_rcu(&(entry->ksym_hlist), &ksym_filter_head);

	ksym_filter_entry_count++;



	return 0;

err:

	if (entry->ksym_hbp)

		kfree(entry->ksym_hbp->info.name);

	kfree(entry->ksym_hbp);

	kfree(entry);

	return ret;

}



static ssize_t ksym_trace_filter_read(struct file *filp, char __user *ubuf,
@@ -289,7 +294,7 @@ static ssize_t ksym_trace_filter_write(struct file *file, 
			if (entry->ksym_hbp->info.type != op)

				changed = 1;

			else

				goto err_ret;

				goto out;

			break;

		}

	}
@@ -298,34 +303,29 @@ static ssize_t ksym_trace_filter_write(struct file *file, 
		entry->ksym_hbp->info.type = op;

		if (op > 0) {

			ret = register_kernel_hw_breakpoint(entry->ksym_hbp);

			if (ret == 0) {

				ret = count;

				goto unlock_ret_path;

			if (ret == 0)

				goto out;

		}

		} else

			ret = count;

		ksym_filter_entry_count--;

		hlist_del_rcu(&(entry->ksym_hlist));

		synchronize_rcu();

		kfree(entry->ksym_hbp->info.name);

		kfree(entry->ksym_hbp);

		kfree(entry);

		goto err_ret;

		goto out;

	} else {

		/* Check for malformed request: (4) */

		if (op == 0)

			goto err_ret;

			goto out;

		ret = process_new_ksym_entry(ksymname, op, ksym_addr);

		if (ret)

			goto err_ret;

	}

	ret = count;

	goto unlock_ret_path;

out:

	mutex_unlock(&ksym_tracer_mutex);



err_ret:

	kfree(input_string);



unlock_ret_path:

	mutex_unlock(&ksym_tracer_mutex);

	if (!ret)

		ret = count;

	return ret;

}
@@ -349,13 +349,6 @@ static void ksym_trace_reset(struct trace_array *tr) 
		ksym_filter_entry_count--;

		hlist_del_rcu(&(entry->ksym_hlist));

		synchronize_rcu();

		/* Free the 'input_string' only if reset

		 * after startup self-test

		 */

#ifdef CONFIG_FTRACE_SELFTEST

		if (strncmp(entry->ksym_hbp->info.name, KSYM_SELFTEST_ENTRY,

					strlen(KSYM_SELFTEST_ENTRY)) != 0)

#endif /* CONFIG_FTRACE_SELFTEST*/

		kfree(entry->ksym_hbp->info.name);

		kfree(entry->ksym_hbp);

		kfree(entry);