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Code Issues Releases Wiki Activity

tracing/cfi: Fix cmp_entries_* functions signature mismatch

Browse source 
If CONFIG_CFI_CLANG=y, attempting to read an event histogram will cause
the kernel to panic due to failed CFI check.

    1. echo 'hist:keys=common_pid' >> events/sched/sched_switch/trigger
    2. cat events/sched/sched_switch/hist
    3. kernel panics on attempting to read hist

This happens because the sort() function expects a generic
int (*)(const void *, const void *) pointer for the compare function.
To prevent this CFI failure, change tracing map cmp_entries_* function
signatures to match this.

Also, fix the build error reported by the kernel test robot [1].

[1] https://lore.kernel.org/r/202110141140.zzi4dRh4-lkp@intel.com/

Link: https://lkml.kernel.org/r/20211014045217.3265162-1-kaleshsingh@google.com

Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Kalesh Singh 2021-10-13 21:52:17 -07:00 committed by Steven Rostedt (VMware)
parent 34cdd18b8d
commit 7ce1bb83a1
1 changed files with 23 additions and 17 deletions
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40
kernel/trace/tracing_map.c
View file

@ -834,29 +834,35 @@ int tracing_map_init(struct tracing_map *map)
return err;
}
static int cmp_entries_dup(const struct tracing_map_sort_entry **a,
const struct tracing_map_sort_entry **b)
static int cmp_entries_dup(const void *A, const void *B)
{
const struct tracing_map_sort_entry *a, *b;
int ret = 0;
if (memcmp((*a)->key, (*b)->key, (*a)->elt->map->key_size))
a = *(const struct tracing_map_sort_entry **)A;
b = *(const struct tracing_map_sort_entry **)B;
if (memcmp(a->key, b->key, a->elt->map->key_size))
ret = 1;
return ret;
}
static int cmp_entries_sum(const struct tracing_map_sort_entry **a,
const struct tracing_map_sort_entry **b)
static int cmp_entries_sum(const void *A, const void *B)
{
const struct tracing_map_elt *elt_a, *elt_b;
const struct tracing_map_sort_entry *a, *b;
struct tracing_map_sort_key *sort_key;
struct tracing_map_field *field;
tracing_map_cmp_fn_t cmp_fn;
void *val_a, *val_b;
int ret = 0;
elt_a = (*a)->elt;
elt_b = (*b)->elt;
a = *(const struct tracing_map_sort_entry **)A;
b = *(const struct tracing_map_sort_entry **)B;
elt_a = a->elt;
elt_b = b->elt;
sort_key = &elt_a->map->sort_key;
@ -873,18 +879,21 @@ static int cmp_entries_sum(const struct tracing_map_sort_entry **a,
return ret;
}
static int cmp_entries_key(const struct tracing_map_sort_entry **a,
const struct tracing_map_sort_entry **b)
static int cmp_entries_key(const void *A, const void *B)
{
const struct tracing_map_elt *elt_a, *elt_b;
const struct tracing_map_sort_entry *a, *b;
struct tracing_map_sort_key *sort_key;
struct tracing_map_field *field;
tracing_map_cmp_fn_t cmp_fn;
void *val_a, *val_b;
int ret = 0;
elt_a = (*a)->elt;
elt_b = (*b)->elt;
a = *(const struct tracing_map_sort_entry **)A;
b = *(const struct tracing_map_sort_entry **)B;
elt_a = a->elt;
elt_b = b->elt;
sort_key = &elt_a->map->sort_key;
@ -989,10 +998,8 @@ static void sort_secondary(struct tracing_map *map,
struct tracing_map_sort_key *primary_key,
struct tracing_map_sort_key *secondary_key)
{
int (*primary_fn)(const struct tracing_map_sort_entry **,
const struct tracing_map_sort_entry **);
int (*secondary_fn)(const struct tracing_map_sort_entry **,
const struct tracing_map_sort_entry **);
int (*primary_fn)(const void *, const void *);
int (*secondary_fn)(const void *, const void *);
unsigned i, start = 0, n_sub = 1;
if (is_key(map, primary_key->field_idx))
@ -1061,8 +1068,7 @@ int tracing_map_sort_entries(struct tracing_map *map,
unsigned int n_sort_keys,
struct tracing_map_sort_entry ***sort_entries)
{
int (*cmp_entries_fn)(const struct tracing_map_sort_entry **,
const struct tracing_map_sort_entry **);
int (*cmp_entries_fn)(const void *, const void *);
struct tracing_map_sort_entry *sort_entry, **entries;
int i, n_entries, ret;