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Diffstat (limited to 'kernel/trace/ftrace.c')
-rw-r--r--kernel/trace/ftrace.c77
1 files changed, 49 insertions, 28 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index a12aff849c04..f9821a3374e9 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1622,6 +1622,11 @@ static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
return keep_regs;
}
+static struct ftrace_ops *
+ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
+static struct ftrace_ops *
+ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
+
static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
int filter_hash,
bool inc)
@@ -1750,15 +1755,17 @@ static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
}
/*
- * If the rec had TRAMP enabled, then it needs to
- * be cleared. As TRAMP can only be enabled iff
- * there is only a single ops attached to it.
- * In otherwords, always disable it on decrementing.
- * In the future, we may set it if rec count is
- * decremented to one, and the ops that is left
- * has a trampoline.
+ * The TRAMP needs to be set only if rec count
+ * is decremented to one, and the ops that is
+ * left has a trampoline. As TRAMP can only be
+ * enabled if there is only a single ops attached
+ * to it.
*/
- rec->flags &= ~FTRACE_FL_TRAMP;
+ if (ftrace_rec_count(rec) == 1 &&
+ ftrace_find_tramp_ops_any(rec))
+ rec->flags |= FTRACE_FL_TRAMP;
+ else
+ rec->flags &= ~FTRACE_FL_TRAMP;
/*
* flags will be cleared in ftrace_check_record()
@@ -1768,7 +1775,7 @@ static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
count++;
/* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
- update |= ftrace_test_record(rec, 1) != FTRACE_UPDATE_IGNORE;
+ update |= ftrace_test_record(rec, true) != FTRACE_UPDATE_IGNORE;
/* Shortcut, if we handled all records, we are done. */
if (!all && count == hash->count)
@@ -1951,11 +1958,6 @@ static void print_ip_ins(const char *fmt, const unsigned char *p)
printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
}
-static struct ftrace_ops *
-ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
-static struct ftrace_ops *
-ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
-
enum ftrace_bug_type ftrace_bug_type;
const void *ftrace_expected;
@@ -2047,7 +2049,7 @@ void ftrace_bug(int failed, struct dyn_ftrace *rec)
}
}
-static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
+static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
{
unsigned long flag = 0UL;
@@ -2146,28 +2148,28 @@ static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
/**
* ftrace_update_record, set a record that now is tracing or not
* @rec: the record to update
- * @enable: set to 1 if the record is tracing, zero to force disable
+ * @enable: set to true if the record is tracing, false to force disable
*
* The records that represent all functions that can be traced need
* to be updated when tracing has been enabled.
*/
-int ftrace_update_record(struct dyn_ftrace *rec, int enable)
+int ftrace_update_record(struct dyn_ftrace *rec, bool enable)
{
- return ftrace_check_record(rec, enable, 1);
+ return ftrace_check_record(rec, enable, true);
}
/**
* ftrace_test_record, check if the record has been enabled or not
* @rec: the record to test
- * @enable: set to 1 to check if enabled, 0 if it is disabled
+ * @enable: set to true to check if enabled, false if it is disabled
*
* The arch code may need to test if a record is already set to
* tracing to determine how to modify the function code that it
* represents.
*/
-int ftrace_test_record(struct dyn_ftrace *rec, int enable)
+int ftrace_test_record(struct dyn_ftrace *rec, bool enable)
{
- return ftrace_check_record(rec, enable, 0);
+ return ftrace_check_record(rec, enable, false);
}
static struct ftrace_ops *
@@ -2356,7 +2358,7 @@ unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
}
static int
-__ftrace_replace_code(struct dyn_ftrace *rec, int enable)
+__ftrace_replace_code(struct dyn_ftrace *rec, bool enable)
{
unsigned long ftrace_old_addr;
unsigned long ftrace_addr;
@@ -2395,7 +2397,7 @@ void __weak ftrace_replace_code(int mod_flags)
{
struct dyn_ftrace *rec;
struct ftrace_page *pg;
- int enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
+ bool enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL;
int failed;
@@ -2935,14 +2937,13 @@ static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
p = &pg->records[i];
p->flags = rec_flags;
-#ifndef CC_USING_NOP_MCOUNT
/*
* Do the initial record conversion from mcount jump
* to the NOP instructions.
*/
- if (!ftrace_code_disable(mod, p))
+ if (!__is_defined(CC_USING_NOP_MCOUNT) &&
+ !ftrace_code_disable(mod, p))
break;
-#endif
update_cnt++;
}
@@ -3094,6 +3095,14 @@ t_probe_next(struct seq_file *m, loff_t *pos)
hnd = &iter->probe_entry->hlist;
hash = iter->probe->ops.func_hash->filter_hash;
+
+ /*
+ * A probe being registered may temporarily have an empty hash
+ * and it's at the end of the func_probes list.
+ */
+ if (!hash || hash == EMPTY_HASH)
+ return NULL;
+
size = 1 << hash->size_bits;
retry:
@@ -4221,10 +4230,13 @@ void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
struct ftrace_func_entry *entry;
struct ftrace_func_map *map;
struct hlist_head *hhd;
- int size = 1 << mapper->hash.size_bits;
- int i;
+ int size, i;
+
+ if (!mapper)
+ return;
if (free_func && mapper->hash.count) {
+ size = 1 << mapper->hash.size_bits;
for (i = 0; i < size; i++) {
hhd = &mapper->hash.buckets[i];
hlist_for_each_entry(entry, hhd, hlist) {
@@ -4316,12 +4328,21 @@ register_ftrace_function_probe(char *glob, struct trace_array *tr,
mutex_unlock(&ftrace_lock);
+ /*
+ * Note, there's a small window here that the func_hash->filter_hash
+ * may be NULL or empty. Need to be carefule when reading the loop.
+ */
mutex_lock(&probe->ops.func_hash->regex_lock);
orig_hash = &probe->ops.func_hash->filter_hash;
old_hash = *orig_hash;
hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
+ if (!hash) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
ret = ftrace_match_records(hash, glob, strlen(glob));
/* Nothing found? */
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