From: Eric Dumazet edumazet@google.com
stable inclusion from stable-v5.10.103 commit 7ef94bfb08fb9e73defafbd5ddef6b5a0e2ee12b bugzilla: https://gitee.com/openeuler/kernel/issues/I56NE7
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit 75134f16e7dd0007aa474b281935c5f42e79f2c8 upstream.
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") Reported-by: syzbot syzkaller@googlegroups.com Signed-off-by: Eric Dumazet edumazet@google.com Signed-off-by: Alexei Starovoitov ast@kernel.org Reviewed-by: Stanislav Fomichev sdf@google.com Acked-by: Brian Vazquez brianvv@google.com Link: https://lore.kernel.org/bpf/20220217181902.808742-1-eric.dumazet@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yu Liao liaoyu15@huawei.com Reviewed-by: Wei Li liwei391@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- kernel/bpf/syscall.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 209e6567cdab..419dbc3d060e 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1308,6 +1308,7 @@ 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; @@ -1365,6 +1366,7 @@ int generic_map_update_batch(struct bpf_map *map,
if (err) break; + cond_resched(); }
if (copy_to_user(&uattr->batch.count, &cp, sizeof(cp))) @@ -1462,6 +1464,7 @@ int generic_map_lookup_batch(struct bpf_map *map, swap(prev_key, key); retry = MAP_LOOKUP_RETRIES; cp++; + cond_resched(); }
if (err == -EFAULT)