Merge branch 'bpf: fix a bpf_timer initialization issue'

Yonghong Song says: ==================== The patch [1] exposed a bpf_timer initialization bug in function check_and_init_map_value(). With bug fix here, the patch [1] can be applied with all selftests passed. Please see individual patches for fix details. [1] https://lore.kernel.org/bpf/[email protected]/ Changelog: v3 -> v4: . move header file in patch #1 to avoid bpf-next merge conflict v2 -> v3: . switch patch #1 and patch #2 for better bisecting v1 -> v2: . add Fixes tag for patch #1 . rebase against bpf tree ==================== Signed-off-by: Alexei Starovoitov <[email protected]>
kernel-patches · Feb 11, 2022 · 3df9d80 · 3df9d80
2 parents acc3c47 + 5eaed6e
commit 3df9d80
Show file tree

Hide file tree

Showing 2 changed files with 4 additions and 4 deletions.
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
@@ -209,11 +209,9 @@ static inline bool map_value_has_timer(const struct bpf_map *map)
 static inline void check_and_init_map_value(struct bpf_map *map, void *dst)
 {
 	if (unlikely(map_value_has_spin_lock(map)))
-		*(struct bpf_spin_lock *)(dst + map->spin_lock_off) =
-			(struct bpf_spin_lock){};
+		memset(dst + map->spin_lock_off, 0, sizeof(struct bpf_spin_lock));
 	if (unlikely(map_value_has_timer(map)))
-		*(struct bpf_timer *)(dst + map->timer_off) =
-			(struct bpf_timer){};
+		memset(dst + map->timer_off, 0, sizeof(struct bpf_timer));
 }
 
 /* copy everything but bpf_spin_lock and bpf_timer. There could be one of each. */

diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
@@ -2,6 +2,7 @@
 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
  */
 #include <linux/bpf.h>
+#include <linux/btf.h>
 #include <linux/bpf-cgroup.h>
 #include <linux/rcupdate.h>
 #include <linux/random.h>
@@ -1075,6 +1076,7 @@ static enum hrtimer_restart bpf_timer_cb(struct hrtimer *hrtimer)
 	void *key;
 	u32 idx;
 
+	BTF_TYPE_EMIT(struct bpf_timer);
 	callback_fn = rcu_dereference_check(t->callback_fn, rcu_read_lock_bh_held());
 	if (!callback_fn)
 		goto out;