Commit 75134f16 authored by Eric Dumazet's avatar Eric Dumazet Committed by Alexei Starovoitov

bpf: Add schedule points in batch ops

syzbot reported various soft lockups caused by bpf batch operations.

 INFO: task kworker/1:1:27 blocked for more than 140 seconds.
 INFO: task hung in rcu_barrier

Nothing prevents batch ops to process huge amount of data,
we need to add schedule points in them.

Note that maybe_wait_bpf_programs(map) calls from
generic_map_delete_batch() can be factorized by moving
the call after the loop.

This will be done later in -next tree once we get this fix merged,
unless there is strong opinion doing this optimization sooner.

Fixes: aa2e93b8 ("bpf: Add generic support for update and delete batch ops")
Fixes: cb4d03ab ("bpf: Add generic support for lookup batch op")
Reported-by: default avatarsyzbot <syzkaller@googlegroups.com>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Reviewed-by: default avatarStanislav Fomichev <sdf@google.com>
Acked-by: default avatarBrian Vazquez <brianvv@google.com>
Link: https://lore.kernel.org/bpf/20220217181902.808742-1-eric.dumazet@gmail.com
parent 45ce4b4f
...@@ -1355,6 +1355,7 @@ int generic_map_delete_batch(struct bpf_map *map, ...@@ -1355,6 +1355,7 @@ int generic_map_delete_batch(struct bpf_map *map,
maybe_wait_bpf_programs(map); maybe_wait_bpf_programs(map);
if (err) if (err)
break; break;
cond_resched();
} }
if (copy_to_user(&uattr->batch.count, &cp, sizeof(cp))) if (copy_to_user(&uattr->batch.count, &cp, sizeof(cp)))
err = -EFAULT; err = -EFAULT;
...@@ -1412,6 +1413,7 @@ int generic_map_update_batch(struct bpf_map *map, ...@@ -1412,6 +1413,7 @@ int generic_map_update_batch(struct bpf_map *map,
if (err) if (err)
break; break;
cond_resched();
} }
if (copy_to_user(&uattr->batch.count, &cp, sizeof(cp))) if (copy_to_user(&uattr->batch.count, &cp, sizeof(cp)))
...@@ -1509,6 +1511,7 @@ int generic_map_lookup_batch(struct bpf_map *map, ...@@ -1509,6 +1511,7 @@ int generic_map_lookup_batch(struct bpf_map *map,
swap(prev_key, key); swap(prev_key, key);
retry = MAP_LOOKUP_RETRIES; retry = MAP_LOOKUP_RETRIES;
cp++; cp++;
cond_resched();
} }
if (err == -EFAULT) if (err == -EFAULT)
......
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