Commit 4aeb6967 authored by Steven Rostedt's avatar Steven Rostedt Committed by Steven Rostedt

tracing: Replace typecasted void pointer in set_ftrace_filter code

The set_ftrace_filter uses seq_file and reads from two lists. The
pointer returned by t_next() can either be of type struct dyn_ftrace
or struct ftrace_func_probe. If there is a bug (there was one)
the wrong pointer may be used and the reference can cause an oops.

This patch makes t_next() and friends only return the iterator structure
which now has a pointer of type struct dyn_ftrace and struct
ftrace_func_probe. The t_show() can now test if the pointer is NULL or
not and if the pointer exists, it is guaranteed to be of the correct type.

Now if there's a bug, only wrong data will be shown but not an oops.

Cc: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 2bccfffd
......@@ -1368,25 +1368,29 @@ enum {
#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
struct ftrace_iterator {
loff_t func_pos;
struct ftrace_page *pg;
int hidx;
int idx;
unsigned flags;
struct trace_parser parser;
loff_t func_pos;
struct ftrace_page *pg;
struct dyn_ftrace *func;
struct ftrace_func_probe *probe;
struct trace_parser parser;
int hidx;
int idx;
unsigned flags;
};
static void *
t_hash_next(struct seq_file *m, void *v, loff_t *pos)
t_hash_next(struct seq_file *m, loff_t *pos)
{
struct ftrace_iterator *iter = m->private;
struct hlist_node *hnd = v;
struct hlist_node *hnd = NULL;
struct hlist_head *hhd;
WARN_ON(!(iter->flags & FTRACE_ITER_HASH));
(*pos)++;
if (iter->probe)
hnd = &iter->probe->node;
retry:
if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
return NULL;
......@@ -1409,7 +1413,12 @@ t_hash_next(struct seq_file *m, void *v, loff_t *pos)
}
}
return hnd;
if (WARN_ON_ONCE(!hnd))
return NULL;
iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
return iter;
}
static void *t_hash_start(struct seq_file *m, loff_t *pos)
......@@ -1428,19 +1437,24 @@ static void *t_hash_start(struct seq_file *m, loff_t *pos)
iter->hidx = 0;
for (l = 0; l <= (*pos - iter->func_pos); ) {
p = t_hash_next(m, p, &l);
p = t_hash_next(m, &l);
if (!p)
break;
}
return p;
if (!p)
return NULL;
return iter;
}
static int t_hash_show(struct seq_file *m, void *v)
static int
t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
{
struct ftrace_func_probe *rec;
struct hlist_node *hnd = v;
rec = hlist_entry(hnd, struct ftrace_func_probe, node);
rec = iter->probe;
if (WARN_ON_ONCE(!rec))
return -EIO;
if (rec->ops->print)
return rec->ops->print(m, rec->ip, rec->ops, rec->data);
......@@ -1461,7 +1475,7 @@ t_next(struct seq_file *m, void *v, loff_t *pos)
struct dyn_ftrace *rec = NULL;
if (iter->flags & FTRACE_ITER_HASH)
return t_hash_next(m, v, pos);
return t_hash_next(m, pos);
(*pos)++;
......@@ -1495,7 +1509,12 @@ t_next(struct seq_file *m, void *v, loff_t *pos)
}
}
return rec;
if (!rec)
return NULL;
iter->func = rec;
return iter;
}
static void *t_start(struct seq_file *m, loff_t *pos)
......@@ -1530,10 +1549,14 @@ static void *t_start(struct seq_file *m, loff_t *pos)
break;
}
if (!p && iter->flags & FTRACE_ITER_FILTER)
return t_hash_start(m, pos);
if (!p) {
if (iter->flags & FTRACE_ITER_FILTER)
return t_hash_start(m, pos);
return p;
return NULL;
}
return iter;
}
static void t_stop(struct seq_file *m, void *p)
......@@ -1544,16 +1567,18 @@ static void t_stop(struct seq_file *m, void *p)
static int t_show(struct seq_file *m, void *v)
{
struct ftrace_iterator *iter = m->private;
struct dyn_ftrace *rec = v;
struct dyn_ftrace *rec;
if (iter->flags & FTRACE_ITER_HASH)
return t_hash_show(m, v);
return t_hash_show(m, iter);
if (iter->flags & FTRACE_ITER_PRINTALL) {
seq_printf(m, "#### all functions enabled ####\n");
return 0;
}
rec = iter->func;
if (!rec)
return 0;
......
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