Few patches that should have been there from day 1.
Anyway, they are coming now.
Signed-off-by: Benjamin Tissoires <[email protected]>
---
Changes in v2:
- fix wq in hashtabs not being freed (and static call not being used)
- Link to v1: https://lore.kernel.org/r/[email protected]
---
Benjamin Tissoires (3):
bpf: do not walk twice the map on free
bpf: do not walk twice the hash map on free
selftests/bpf: drop an unused local variable
kernel/bpf/arraymap.c | 15 ++++-----
kernel/bpf/hashtab.c | 49 ++++++++---------------------
tools/testing/selftests/bpf/prog_tests/wq.c | 2 --
3 files changed, 21 insertions(+), 45 deletions(-)
---
base-commit: 1bba3b3d373dbafae891e7cb06b8c82c8d62aba1
change-id: 20240425-bpf-next-2114350587e3
Best regards,
--
Benjamin Tissoires <[email protected]>
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 <[email protected]>
---
changes in v2:
- fix wq being not freed (and static call not used)
---
kernel/bpf/hashtab.c | 49 +++++++++++++------------------------------------
1 file changed, 13 insertions(+), 36 deletions(-)
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index 0179183c543a..5eefadfc8ea9 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -221,32 +221,11 @@ static bool htab_has_extra_elems(struct bpf_htab *htab)
return !htab_is_percpu(htab) && !htab_is_lru(htab);
}
-static void htab_free_prealloced_timers(struct bpf_htab *htab)
+static void htab_free_prealloced_timers_and_wq(struct bpf_htab *htab)
{
u32 num_entries = htab->map.max_entries;
int i;
- if (!btf_record_has_field(htab->map.record, BPF_TIMER))
- return;
- if (htab_has_extra_elems(htab))
- num_entries += num_possible_cpus();
-
- for (i = 0; i < num_entries; i++) {
- struct htab_elem *elem;
-
- elem = get_htab_elem(htab, i);
- bpf_obj_free_timer(htab->map.record, elem->key + round_up(htab->map.key_size, 8));
- cond_resched();
- }
-}
-
-static void htab_free_prealloced_wq(struct bpf_htab *htab)
-{
- u32 num_entries = htab->map.max_entries;
- int i;
-
- if (!btf_record_has_field(htab->map.record, BPF_WORKQUEUE))
- return;
if (htab_has_extra_elems(htab))
num_entries += num_possible_cpus();
@@ -254,8 +233,12 @@ static void htab_free_prealloced_wq(struct bpf_htab *htab)
struct htab_elem *elem;
elem = get_htab_elem(htab, i);
- bpf_obj_free_workqueue(htab->map.record,
- elem->key + round_up(htab->map.key_size, 8));
+ if (btf_record_has_field(htab->map.record, BPF_TIMER))
+ bpf_obj_free_timer(htab->map.record,
+ elem->key + round_up(htab->map.key_size, 8));
+ else
+ bpf_obj_free_workqueue(htab->map.record,
+ elem->key + round_up(htab->map.key_size, 8));
cond_resched();
}
}
@@ -1515,7 +1498,7 @@ 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_and_wq(struct bpf_htab *htab)
{
int i;
@@ -1527,10 +1510,10 @@ 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));
}
@@ -1544,17 +1527,11 @@ 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 (!htab_is_prealloc(htab))
- htab_free_malloced_timers_or_wq(htab, true);
- else
- htab_free_prealloced_timers(htab);
- }
- if (btf_record_has_field(htab->map.record, BPF_WORKQUEUE)) {
+ if (btf_record_has_field(htab->map.record, BPF_TIMER | BPF_WORKQUEUE)) {
if (!htab_is_prealloc(htab))
- htab_free_malloced_timers_or_wq(htab, false);
+ htab_free_malloced_timers_and_wq(htab);
else
- htab_free_prealloced_wq(htab);
+ htab_free_prealloced_timers_and_wq(htab);
}
}
--
2.44.0
Some copy/paste leftover, this is never used
Fixes: e3d9eac99afd ("selftests/bpf: wq: add bpf_wq_init() checks")
Signed-off-by: Benjamin Tissoires <[email protected]>
---
no changes in v2
---
tools/testing/selftests/bpf/prog_tests/wq.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/wq.c b/tools/testing/selftests/bpf/prog_tests/wq.c
index c4bacd3160e1..99e438fe12ac 100644
--- a/tools/testing/selftests/bpf/prog_tests/wq.c
+++ b/tools/testing/selftests/bpf/prog_tests/wq.c
@@ -36,7 +36,5 @@ void serial_test_wq(void)
void serial_test_failures_wq(void)
{
- LIBBPF_OPTS(bpf_test_run_opts, topts);
-
RUN_TESTS(wq_failures);
}
--
2.44.0
On Apr 30 2024, Benjamin Tissoires wrote:
> 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 <[email protected]>
>
> ---
>
> changes in v2:
> - fix wq being not freed (and static call not used)
> ---
> kernel/bpf/hashtab.c | 49 +++++++++++++------------------------------------
> 1 file changed, 13 insertions(+), 36 deletions(-)
>
> diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
> index 0179183c543a..5eefadfc8ea9 100644
> --- a/kernel/bpf/hashtab.c
> +++ b/kernel/bpf/hashtab.c
> @@ -221,32 +221,11 @@ static bool htab_has_extra_elems(struct bpf_htab *htab)
> return !htab_is_percpu(htab) && !htab_is_lru(htab);
> }
>
> -static void htab_free_prealloced_timers(struct bpf_htab *htab)
> +static void htab_free_prealloced_timers_and_wq(struct bpf_htab *htab)
> {
> u32 num_entries = htab->map.max_entries;
> int i;
>
> - if (!btf_record_has_field(htab->map.record, BPF_TIMER))
> - return;
> - if (htab_has_extra_elems(htab))
> - num_entries += num_possible_cpus();
> -
> - for (i = 0; i < num_entries; i++) {
> - struct htab_elem *elem;
> -
> - elem = get_htab_elem(htab, i);
> - bpf_obj_free_timer(htab->map.record, elem->key + round_up(htab->map.key_size, 8));
> - cond_resched();
> - }
> -}
> -
> -static void htab_free_prealloced_wq(struct bpf_htab *htab)
> -{
> - u32 num_entries = htab->map.max_entries;
> - int i;
> -
> - if (!btf_record_has_field(htab->map.record, BPF_WORKQUEUE))
> - return;
> if (htab_has_extra_elems(htab))
> num_entries += num_possible_cpus();
>
> @@ -254,8 +233,12 @@ static void htab_free_prealloced_wq(struct bpf_htab *htab)
> struct htab_elem *elem;
>
> elem = get_htab_elem(htab, i);
> - bpf_obj_free_workqueue(htab->map.record,
> - elem->key + round_up(htab->map.key_size, 8));
> + if (btf_record_has_field(htab->map.record, BPF_TIMER))
> + bpf_obj_free_timer(htab->map.record,
> + elem->key + round_up(htab->map.key_size, 8));
> + else
Sorry, this else above is wrong, it should be a check on BPF_WORKQUEUE
instead.
v3 is n its way (with the proper bpf-next suffix this time).
Cheers,
Benjamin
> + bpf_obj_free_workqueue(htab->map.record,
> + elem->key + round_up(htab->map.key_size, 8));
> cond_resched();
> }
> }
> @@ -1515,7 +1498,7 @@ 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_and_wq(struct bpf_htab *htab)
> {
> int i;
>
> @@ -1527,10 +1510,10 @@ 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));
> }
> @@ -1544,17 +1527,11 @@ 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 (!htab_is_prealloc(htab))
> - htab_free_malloced_timers_or_wq(htab, true);
> - else
> - htab_free_prealloced_timers(htab);
> - }
> - if (btf_record_has_field(htab->map.record, BPF_WORKQUEUE)) {
> + if (btf_record_has_field(htab->map.record, BPF_TIMER | BPF_WORKQUEUE)) {
> if (!htab_is_prealloc(htab))
> - htab_free_malloced_timers_or_wq(htab, false);
> + htab_free_malloced_timers_and_wq(htab);
> else
> - htab_free_prealloced_wq(htab);
> + htab_free_prealloced_timers_and_wq(htab);
> }
> }
>
>
> --
> 2.44.0
>