Acked-by: Brian Vazquez <brianvv@xxxxxxxxxx>
On Thu, Feb 17, 2022 at 10:19 AM Eric Dumazet <eric.dumazet@xxxxxxxxx> wrote:
>
> 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
>
