From: Kalesh Singh kaleshsingh@google.com
[ Upstream commit 7ce1bb83a14019f8c396d57ec704d19478747716 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/trace/tracing_map.c | 40 ++++++++++++++++++++++---------------- 1 file changed, 23 insertions(+), 17 deletions(-)
diff --git a/kernel/trace/tracing_map.c b/kernel/trace/tracing_map.c index 4b50fc0cb12c7..d63e51dde0d24 100644 --- a/kernel/trace/tracing_map.c +++ b/kernel/trace/tracing_map.c @@ -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;