If someone stores both a timer and a workqueue in a hash map, on free, we would walk it twice. Add a check in htab_free_malloced_timers_or_wq and free the timers and workqueues if they are present.
Fixes: 246331e3f1ea ("bpf: allow struct bpf_wq to be embedded in arraymaps and hashmaps") Signed-off-by: Benjamin Tissoires bentiss@kernel.org --- kernel/bpf/hashtab.c | 16 +++++----------- 1 file changed, 5 insertions(+), 11 deletions(-)
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c index 0179183c543a..20162ae741e9 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -1515,7 +1515,7 @@ static void delete_all_elements(struct bpf_htab *htab) migrate_enable(); }
-static void htab_free_malloced_timers_or_wq(struct bpf_htab *htab, bool is_timer) +static void htab_free_malloced_timers_or_wq(struct bpf_htab *htab) { int i;
@@ -1527,10 +1527,10 @@ static void htab_free_malloced_timers_or_wq(struct bpf_htab *htab, bool is_timer
hlist_nulls_for_each_entry(l, n, head, hash_node) { /* We only free timer on uref dropping to zero */ - if (is_timer) + if (btf_record_has_field(htab->map.record, BPF_TIMER)) bpf_obj_free_timer(htab->map.record, l->key + round_up(htab->map.key_size, 8)); - else + if (btf_record_has_field(htab->map.record, BPF_WORKQUEUE)) bpf_obj_free_workqueue(htab->map.record, l->key + round_up(htab->map.key_size, 8)); } @@ -1544,18 +1544,12 @@ static void htab_map_free_timers_and_wq(struct bpf_map *map) struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
/* We only free timer and workqueue on uref dropping to zero */ - if (btf_record_has_field(htab->map.record, BPF_TIMER)) { + if (btf_record_has_field(htab->map.record, BPF_TIMER | BPF_WORKQUEUE)) { if (!htab_is_prealloc(htab)) - htab_free_malloced_timers_or_wq(htab, true); + htab_free_malloced_timers_or_wq(htab); else htab_free_prealloced_timers(htab); } - if (btf_record_has_field(htab->map.record, BPF_WORKQUEUE)) { - if (!htab_is_prealloc(htab)) - htab_free_malloced_timers_or_wq(htab, false); - else - htab_free_prealloced_wq(htab); - } }
/* Called when map->refcnt goes to zero, either from workqueue or from syscall */