From: Eric Dumazet <edumazet@xxxxxxxxxx>
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: aa2e93b8e58e ("bpf: Add generic support for update and delete batch ops")
Fixes: cb4d03ab499d ("bpf: Add generic support for lookup batch op")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Brian Vazquez <brianvv@xxxxxxxxxx>
Cc: Stanislav Fomichev <sdf@xxxxxxxxxx>
Reported-by: syzbot <syzkaller@xxxxxxxxxxxxxxxx>
---
kernel/bpf/syscall.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index fa4505f9b6119bcb219ab9733847a98da65d1b21..ca70fe6fba387937dfb54f10826f19ac55a8a8e7 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1355,6 +1355,7 @@ int generic_map_delete_batch(struct bpf_map *map,
maybe_wait_bpf_programs(map);
if (err)
break;
+ cond_resched();
}
if (copy_to_user(&uattr->batch.count, &cp, sizeof(cp)))
err = -EFAULT;
@@ -1412,6 +1413,7 @@ int generic_map_update_batch(struct bpf_map *map,
if (err)
break;
+ cond_resched();
}
if (copy_to_user(&uattr->batch.count, &cp, sizeof(cp)))
@@ -1509,6 +1511,7 @@ int generic_map_lookup_batch(struct bpf_map *map,
swap(prev_key, key);
retry = MAP_LOOKUP_RETRIES;
cp++;
+ cond_resched();
}
if (err == -EFAULT)
--
2.35.1.265.g69c8d7142f-goog
