* [PATCH bpf] bpf: add schedule points in batch ops
@ 2022-02-17 18:19 Eric Dumazet
2022-02-17 18:36 ` sdf
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Eric Dumazet @ 2022-02-17 18:19 UTC (permalink / raw)
To: Alexei Starovoitov, Daniel Borkmann
Cc: David S . Miller, netdev, Eric Dumazet, Eric Dumazet, bpf,
Brian Vazquez, Stanislav Fomichev, syzbot
From: Eric Dumazet <edumazet@google.com>
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@google.com>
Cc: Brian Vazquez <brianvv@google.com>
Cc: Stanislav Fomichev <sdf@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
---
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
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH bpf] bpf: add schedule points in batch ops
2022-02-17 18:19 [PATCH bpf] bpf: add schedule points in batch ops Eric Dumazet
@ 2022-02-17 18:36 ` sdf
2022-02-17 18:37 ` Brian Vazquez
2022-02-17 19:00 ` patchwork-bot+netdevbpf
2 siblings, 0 replies; 4+ messages in thread
From: sdf @ 2022-02-17 18:36 UTC (permalink / raw)
To: Eric Dumazet
Cc: Alexei Starovoitov, Daniel Borkmann, David S . Miller, netdev,
Eric Dumazet, bpf, Brian Vazquez, syzbot
On 02/17, Eric Dumazet wrote:
> From: Eric Dumazet <edumazet@google.com>
> 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@google.com>
> Cc: Brian Vazquez <brianvv@google.com>
> Cc: Stanislav Fomichev <sdf@google.com>
Looks good, thank you!
Reviewed-by: Stanislav Fomichev <sdf@google.com>
> Reported-by: syzbot <syzkaller@googlegroups.com>
> ---
> 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
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH bpf] bpf: add schedule points in batch ops
2022-02-17 18:19 [PATCH bpf] bpf: add schedule points in batch ops Eric Dumazet
2022-02-17 18:36 ` sdf
@ 2022-02-17 18:37 ` Brian Vazquez
2022-02-17 19:00 ` patchwork-bot+netdevbpf
2 siblings, 0 replies; 4+ messages in thread
From: Brian Vazquez @ 2022-02-17 18:37 UTC (permalink / raw)
To: Eric Dumazet
Cc: Alexei Starovoitov, Daniel Borkmann, David S . Miller, netdev,
Eric Dumazet, bpf, Stanislav Fomichev, syzbot
Acked-by: Brian Vazquez <brianvv@google.com>
On Thu, Feb 17, 2022 at 10:19 AM Eric Dumazet <eric.dumazet@gmail.com> wrote:
>
> From: Eric Dumazet <edumazet@google.com>
>
> 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@google.com>
> Cc: Brian Vazquez <brianvv@google.com>
> Cc: Stanislav Fomichev <sdf@google.com>
> Reported-by: syzbot <syzkaller@googlegroups.com>
> ---
> 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
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH bpf] bpf: add schedule points in batch ops
2022-02-17 18:19 [PATCH bpf] bpf: add schedule points in batch ops Eric Dumazet
2022-02-17 18:36 ` sdf
2022-02-17 18:37 ` Brian Vazquez
@ 2022-02-17 19:00 ` patchwork-bot+netdevbpf
2 siblings, 0 replies; 4+ messages in thread
From: patchwork-bot+netdevbpf @ 2022-02-17 19:00 UTC (permalink / raw)
To: Eric Dumazet
Cc: ast, daniel, davem, netdev, edumazet, bpf, brianvv, sdf, syzkaller
Hello:
This patch was applied to bpf/bpf.git (master)
by Alexei Starovoitov <ast@kernel.org>:
On Thu, 17 Feb 2022 10:19:02 -0800 you wrote:
> From: Eric Dumazet <edumazet@google.com>
>
> 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
>
> [...]
Here is the summary with links:
- [bpf] bpf: add schedule points in batch ops
https://git.kernel.org/bpf/bpf/c/75134f16e7dd
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 4+ messages in thread
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2022-02-17 18:19 [PATCH bpf] bpf: add schedule points in batch ops Eric Dumazet
2022-02-17 18:36 ` sdf
2022-02-17 18:37 ` Brian Vazquez
2022-02-17 19:00 ` patchwork-bot+netdevbpf
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