This patch allows bpf iterator programs to use sleepable helpers by
changing `bpf_iter_run_prog` to use the appropriate synchronization.
With sleepable bpf iterator programs, we can no longer use
`rcu_read_lock()` and must use `rcu_read_lock_trace()` instead
to protect the bpf program.
Signed-off-by: Kenny Yu <kennyyu@fb.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220124185403.468466-2-kennyyu@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
#include <linux/anon_inodes.h>
#include <linux/filter.h>
#include <linux/bpf.h>
+#include <linux/rcupdate_trace.h>
struct bpf_iter_target_info {
struct list_head list;
{
int ret;
- rcu_read_lock();
- migrate_disable();
- ret = bpf_prog_run(prog, ctx);
- migrate_enable();
- rcu_read_unlock();
+ if (prog->aux->sleepable) {
+ rcu_read_lock_trace();
+ migrate_disable();
+ might_fault();
+ ret = bpf_prog_run(prog, ctx);
+ migrate_enable();
+ rcu_read_unlock_trace();
+ } else {
+ rcu_read_lock();
+ migrate_disable();
+ ret = bpf_prog_run(prog, ctx);
+ migrate_enable();
+ rcu_read_unlock();
+ }
/* bpf program can only return 0 or 1:
* 0 : okay