From: patchwork-bot+netdevbpf@kernel.org
To: Vlad Poenaru <vlad.wing@gmail.com>
Cc: bpf@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net,
andrii@kernel.org, john.fastabend@gmail.com,
martin.lau@linux.dev, eddyz87@gmail.com, memxor@gmail.com,
song@kernel.org, yonghong.song@linux.dev, jolsa@kernel.org,
toke@redhat.com, emil@etsalapatis.com,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH bpf v2 0/2] bpf, lpm_trie: Allow sleepable BPF programs to use LPM tries
Date: Tue, 09 Jun 2026 19:50:13 +0000 [thread overview]
Message-ID: <178103461364.2620314.3413571029788507354.git-patchwork-notify@kernel.org> (raw)
In-Reply-To: <20260609135558.193287-1-vlad.wing@gmail.com>
Hello:
This series was applied to bpf/bpf-next.git (master)
by Alexei Starovoitov <ast@kernel.org>:
On Tue, 9 Jun 2026 06:55:56 -0700 you wrote:
> trie_lookup_elem() annotates its rcu_dereference_check() walks with only
> rcu_read_lock_bh_held(), so a sleepable BPF program that touches an LPM
> trie (e.g. a sleepable LSM hook calling bpf_map_lookup_elem()) trips a
> "suspicious RCU usage" lockdep splat on debug kernels: it holds only
> rcu_read_lock_trace(), which that annotation does not accept.
>
> Patch 1 relaxes the rcu_dereference annotations in the trie walks so they
> no longer trip lockdep from the Tasks Trace context, including the
> trie_update_elem()/trie_delete_elem() writer walks (protected by
> trie->lock). Patch 2 adds BPF_MAP_TYPE_LPM_TRIE to the verifier's
> sleepable map whitelist so sleepable programs can reference an LPM trie
> directly, not just as the inner map of a map-of-maps. LPM trie nodes are
> reclaimed via bpf_mem_cache_free_rcu(), which chains a regular RCU grace
> period into a Tasks Trace grace period before freeing -- the same
> discipline BPF_MAP_TYPE_HASH relies on for sleepable access.
>
> [...]
Here is the summary with links:
- [bpf,v2,1/2] bpf, lpm_trie: Allow access from sleepable BPF programs
https://git.kernel.org/bpf/bpf-next/c/2f884d371faf
- [bpf,v2,2/2] bpf, lpm_trie: Allow sleepable programs to use LPM trie maps directly
https://git.kernel.org/bpf/bpf-next/c/a3d76e27bbbf
You are awesome, thank you!
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prev parent reply other threads:[~2026-06-09 19:50 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-29 17:42 [PATCH bpf] bpf, lpm_trie: Allow lookups from sleepable BPF programs Vlad Poenaru
2026-05-29 19:19 ` Emil Tsalapatis
2026-06-09 13:55 ` [PATCH bpf v2 0/2] bpf, lpm_trie: Allow sleepable BPF programs to use LPM tries Vlad Poenaru
2026-06-09 13:55 ` [PATCH bpf v2 1/2] bpf, lpm_trie: Allow access from sleepable BPF programs Vlad Poenaru
2026-06-09 16:36 ` Emil Tsalapatis
2026-06-09 13:55 ` [PATCH bpf v2 2/2] bpf, lpm_trie: Allow sleepable programs to use LPM trie maps directly Vlad Poenaru
2026-06-09 16:19 ` Emil Tsalapatis
2026-06-10 1:53 ` Hou Tao
2026-06-10 2:34 ` Alexei Starovoitov
2026-06-09 19:50 ` patchwork-bot+netdevbpf [this message]
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