Hello:
This patch was applied to bpf/bpf-next.git (master)
by Alexei Starovoitov <ast@xxxxxxxxxx>:
On Tue, 18 Mar 2025 11:27:59 -0700 you wrote:
> From: Martin KaFai Lau <martin.lau@xxxxxxxxxx>
>
> The current cgrp storage has a percpu counter, bpf_cgrp_storage_busy,
> to detect potential deadlock at a spin_lock that the local storage
> acquires during new storage creation.
>
> There are false positives. It turns out to be too noisy in
> production. For example, a bpf prog may be doing a
> bpf_cgrp_storage_get on map_a. An IRQ comes in and triggers
> another bpf_cgrp_storage_get on a different map_b. It will then
> trigger the false positive deadlock check in the percpu counter.
> On top of that, both are doing lookup only and no need to create
> new storage, so practically it does not need to acquire
> the spin_lock.
>
> [...]
Here is the summary with links:
- [bpf-next] bpf: Only fails the busy counter check in bpf_cgrp_storage_get if it creates storage
https://git.kernel.org/bpf/bpf-next/c/f4edc66e48a6
You are awesome, thank you!
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