[tip:perf/core] ksym_tracer: Fix memory leak

tip-bot for Li Zefan
2009-11-21T13:35:50Z

Commit-ID: 558df6c8f74ac4a0b9026ef85b0028280f364d96
Gitweb: http://git.kernel.org/tip/558df6c8f74ac4a0b9026ef85b0028280f364d96
Author: Li Zefan <lizf@cn.fujitsu.com>
AuthorDate: Tue, 7 Jul 2009 13:54:48 +0800
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 10 Jul 2009 11:59:43 +0200

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: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Frederic 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: Ingo Molnar <mingo@elte.hu>
---
kernel/trace/trace_ksym.c | 61 ++++++++++++++++++++-------------------------
1 files changed, 27 insertions(+), 34 deletions(-)

diff --git a/kernel/trace/trace_ksym.c b/kernel/trace/trace_ksym.c
index 891e3b8..7d349d3 100644
--- a/kernel/trace/trace_ksym.c
+++ b/kernel/trace/trace_ksym.c
@@ -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;
- }
- } else
- ret = count;
+ if (ret == 0)
+ goto out;
+ }
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;
}

@@ -349,14 +349,7 @@ 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->info.name);
kfree(entry->ksym_hbp);
kfree(entry);
}