From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-176.mta1.migadu.com (out-176.mta1.migadu.com [95.215.58.176]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4B65F306B06; Wed, 26 Nov 2025 16:24:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.176 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764174272; cv=none; b=eIUi9IeWfSIJhUjbTR5Wv2eeL0yM7cWWAJRMG32V6xL9lK8IaPqFRcaOZ+pvsNtLO+flfyUJ6PwlVK4BKC/SovrNY8GX18gKFdjXJ5eSD07vvtViJZtiBNHxg3DwRQOAi1bIxyWSVdIUPKtKFwg9QK42fPvPf9SBlKaO7obKaUI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764174272; c=relaxed/simple; bh=jVuT3OlGm7eNi3eYEGZFHHFSDumDXBBchOQE3Jg8Y/k=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=u7XdvU76xfKEV2iJzcf7ovrGV7G5EBtmVtpI9zO/zbUHXX88h+wkt4BAI90fYgcUmFWUPjmjylcPRhiocvxWcUj6y9KSCCIxqRW0qRdY4IQV1JqZX+mPV8NNU7R2zmR0/ObfH6ZALTB7/siM+azEXt8BUUwpnlKFR+et3auzxvk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=o6EBdzbB; arc=none smtp.client-ip=95.215.58.176 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="o6EBdzbB" Message-ID: <13a871d1-5bd8-44a1-8737-eb26342d30b4@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1764174268; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ekRT332AhugTObU/O7d0SgsnySfkt/B3bfRW4qi1c38=; b=o6EBdzbBfRSNbqrzyNQy0/jwq3rhnUJY9BWQHLJn0k5zdTTvjgAf2+V1BfVRd9qHfpD1eu HUOSsk4Vk3QsZwRXXY7iimxiFnLtr5jxD6NVJCQMPtUO1qh42ZZMvELk9N7h889j5R0uCu YenxpVKMF7xP80JV942cal4X7de7Jk0= Date: Thu, 27 Nov 2025 00:24:10 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH bpf-next v12 3/7] bpf: Add BPF_F_CPU and BPF_F_ALL_CPUS flags support for percpu_hash and lru_percpu_hash maps To: bot+bpf-ci@kernel.org, bpf@vger.kernel.org Cc: ast@kernel.org, andrii@kernel.org, daniel@iogearbox.net, jolsa@kernel.org, yonghong.song@linux.dev, song@kernel.org, eddyz87@gmail.com, dxu@dxuuu.xyz, deso@posteo.net, martin.lau@linux.dev, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, shuah@kernel.org, kerneljasonxing@gmail.com, chen.dylane@linux.dev, willemb@google.com, paul.chaignon@gmail.com, a.s.protopopov@gmail.com, memxor@gmail.com, yatsenko@meta.com, tklauser@distanz.ch, kernel-patches-bot@fb.com, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, martin.lau@kernel.org, clm@meta.com, ihor.solodrai@linux.dev References: <20251126145039.15715-4-leon.hwang@linux.dev> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Leon Hwang In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT On 2025/11/26 23:11, bot+bpf-ci@kernel.org wrote: >> diff --git a/include/linux/bpf.h b/include/linux/bpf.h >> index 01a99e3a3..f79d2ae27 100644 >> --- a/include/linux/bpf.h >> +++ b/include/linux/bpf.h > > [ ... ] > >> diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c >> index c8a9b27f8..441ff5bc5 100644 >> --- a/kernel/bpf/hashtab.c >> +++ b/kernel/bpf/hashtab.c > > [ ... ] > >> @@ -1249,6 +1258,15 @@ static long htab_lru_map_update_elem(struct bpf_map *map, void *key, void *value >> return ret; >> } >> >> +static int htab_map_check_update_flags(bool onallcpus, u64 map_flags) >> +{ >> + if (unlikely(!onallcpus && map_flags > BPF_EXIST)) >> + return -EINVAL; >> + if (unlikely(onallcpus && ((map_flags & BPF_F_LOCK) || (u32)map_flags > BPF_F_ALL_CPUS))) >> + return -EINVAL; >> + return 0; >> +} >> + > > Can htab_map_check_update_flags() correctly validate the new flags? > > When onallcpus=false (the common case for normal map_update_elem > operations via htab_percpu_map_update_elem()-> > htab_map_update_elem_in_place()), the check at the first if statement > compares the full 64-bit map_flags value against BPF_EXIST (2). > > When BPF_F_CPU (8) is set, or when the CPU number is embedded in the > upper 32 bits (e.g., 0x0000000100000008 for CPU 1), map_flags will be > greater than BPF_EXIST, causing this function to return -EINVAL. > > This appears inconsistent with the equivalent check in > bpf_percpu_array_update() (commit 51f40f83b), which uses: > > if (unlikely((map_flags & BPF_F_LOCK) || (u32)map_flags > BPF_F_ALL_CPUS)) > > The percpu_array check casts to u32 to examine only the lower 32 bits, > allowing the CPU number in the upper 32 bits. The hash table check for > onallcpus=false doesn't perform this cast, so it will reject valid flag > combinations that include BPF_F_CPU. > > Would this prevent the BPF_F_CPU functionality from working for normal > percpu_hash update operations? > For UAPI percpu_hash updates, this is fine because onallcpus is always true. For BPF program–initiated percpu_hash updates, the behavior also remains unchanged since onallcpus is false, and the 'map_flags > BPF_EXIST' check behaves exactly as it did before. Thanks, Leon >> @@ -1262,9 +1280,9 @@ static long htab_map_update_elem_in_place(struct bpf_map *map, void *key, >> u32 key_size, hash; >> int ret; >> >> - if (unlikely(map_flags > BPF_EXIST)) >> - /* unknown flags */ >> - return -EINVAL; >> + ret = htab_map_check_update_flags(onallcpus, map_flags); >> + if (unlikely(ret)) >> + return ret; >> >> WARN_ON_ONCE(!bpf_rcu_lock_held()); >> > > [ ... ] > >> @@ -1324,9 +1342,9 @@ static long __htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key, >> u32 key_size, hash; >> int ret; >> >> - if (unlikely(map_flags > BPF_EXIST)) >> - /* unknown flags */ >> - return -EINVAL; >> + ret = htab_map_check_update_flags(onallcpus, map_flags); >> + if (unlikely(ret)) >> + return ret; > > [ ... ] > > > --- > AI reviewed your patch. Please fix the bug or email reply why it's not a bug. > See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md > > CI run summary: https://github.com/kernel-patches/bpf/actions/runs/19708012130