From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792928316; b=CH6r+qP02wB3GWONXvyzvVwWHfbwHxzadH/8xV4nzkr2J9Q8GAnVUF0fgGW6d4SWIjPz vobOeFWWiXgixpjbHMct2u3TM6C2SOvAWjB7a73A62TJvaMmVsa8uDqnkX7llGd2pp2H1 9OpppkMJb2+Gp3mD16MJ4bKRl0FGB3STNVg/gE8GIRwkXKlY/J7vkSbGam8ewaOfG6x3J L1R2S6diWm4zVnHkFrhayshfzq4u5VNuu2DC+DkuMPVV2mGSyfNeIXopSFTkKgey7UGal C0UDG3oWCH4IxlJHh9enOzMv6BW3fnEvgMQUJEuqORfV1uywZ5/ragjTzl+lJ5HWAOA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792928316; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=5gffO8dUYNaYaBcr6gccrSu8nehMwJhPRtf8K+sOayk=; b=4V3zGdYywYfpbw2fqCRZf8N0F1Xc/FjcCFVHzrOera0LiWR5sAPvqwxwh9RJxL/9rIDu idVRUpgWU2BWf5JXHmo49PpRlTok2nm8thJdGNOLoZmu7fF/iVR1wNSLRa9jodqLfFEvH 6EaiuWYD49VR6NURgJlfQnP6n2n2FzRVEi9tbdKrgZoVErelMC50ubpnleNM8BNdJz0O3 b49USsGCB51gMGLg84nl3nFgxmv9e7foPNyqABQsDGkBY3VcbCWUiH8ZEfCAKbFfp7eU0 MCWj9KZeLIjiiQTAQpqsEiQ5ugw0/Rd32oSoZt4iN0EH0qaSvrDr+zhVOOIR5IGdBnA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=fopzLHoh; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E45B8606A31A for ; Sun, 25 Oct 2026 11:38:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=fopzLHoh Received: by smtp.kernel.org (Postfix) with ESMTPSA id 596641F01825; Sun, 25 Oct 2026 11:38:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792928315; bh=5gffO8dUYNaYaBcr6gccrSu8nehMwJhPRtf8K+sOayk=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=fopzLHoheOQ1SHB0CYsGsSnf3DSLDTu2BQWj9btooybOYr2MWk322hFbxMolzAcvx 4vn2PptmwsMnQn5zN9EtZANk5BD9ip/vhQLDhB8Is6AjHX/J3z0Oald6y5E3Q/IMLg jNNkOn6KDtYnbV7ZDpYuR24PWey5ocVTyfz+j10rZpgQsex4Tt2z+s5pqrDREM+LVS Ntf0/cKiGuB3DKnBkc1bWIyQ4v5TNvFuKje/GrjW3Gnz8V79wWMoVbIhE2blnTIkHn n1CDFM74rkx59J9h3f8VwyNLkzmPBUNDoj2W8p7uj+tg1zepEHVXrgZdMP21d6ht7i DxhIENmONggqg== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH RFC bpf-next 1/2] bpf: Keep recursion-checked trampoline programs non-preemptible on !PREEMPT_RT Reply-To: sashiko-reviews@lists.linux.dev To: "Mike Bazov" Cc: bpf@vger.kernel.org In-Reply-To: <20261025-b4-bpf-trampoline-preempt-v1-1-198dcdc0c6ac@sentinelone.com> References: <20261025-b4-bpf-trampoline-preempt-v1-0-198dcdc0c6ac@sentinelone.com> <20261025-b4-bpf-trampoline-preempt-v1-1-198dcdc0c6ac@sentinelone.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Sun, 25 Oct 2026 11:38:34 +0000 X-Mailing-List: bpf@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list Thank you for your contribution! Sashiko AI review found 1 potential issue(= s) to consider: - [Low] bpf: multi-line comment style violation in __bpf_prog_enter_recur() -- commit 264a83620cb7c053d29054a8d674730e0e75ac83 Author: Mike Bazov bpf: Keep recursion-checked trampoline programs non-preemptible on !PREEMPT= _RT This commit disables preemption in __bpf_prog_enter_recur() and __bpf_prog_exit_recur() when CONFIG_PREEMPT_RT is disabled so that per-CPU recursion tracking and per-CPU private stacks are not shared across preempted tasks on the same CPU. > diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c > index bf4cb3dd444d6..632c104112b2e 100644 > --- a/kernel/bpf/trampoline.c > +++ b/kernel/bpf/trampoline.c > @@ -1339,7 +1339,15 @@ static __always_inline u64 notrace bpf_prog_start_= time(void) > static u64 notrace __bpf_prog_enter_recur(struct bpf_prog *prog, struct = bpf_tramp_run_ctx *run_ctx) > __acquires(RCU) > { > - rcu_read_lock_dont_migrate(); > + if (IS_ENABLED(CONFIG_PREEMPT_RT)) { > + rcu_read_lock_dont_migrate(); > + } else { > + /* prog->active and the private stack are per-CPU: don't let > + * another task run on this CPU while we hold them. > + */ [Severity: Low] This isn't a bug, but in __bpf_prog_enter_recur() in kernel/bpf/trampoline.c, could this multi-line comment place the opening /* on its own line to follow the BPF subsystem comment style? /* * prog->active and the private stack are per-CPU: don't let * another task run on this CPU while we hold them. */ --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261025-b4-bpf-tra= mpoline-preempt-v1-0-198dcdc0c6ac@sentinelone.com?part=3D1