From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f41.google.com (mail-pj1-f41.google.com [209.85.216.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A008E2D058 for ; Mon, 8 Jul 2024 22:16:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.41 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720476972; cv=none; b=aBhwcpiHbXKU6Jz6u64RjBEUb4X7Lr6jzVNZVQoS/ipkrsYe+BYQ4d8s6a5tbT6x1G75m65jidNUzf1s+MF4FZKog1zNQrBPTl1HEecygG3w7vvD+87tgwzklwUq44Oqfx8dad06fugJVLmbUkbL4oSk9abk2IdcgzDAf4Vp9eY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720476972; c=relaxed/simple; bh=h6vq6ownG6HIDtryCrk+PoGOueJGzfS405DNiCfiatc=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=GRnsXoZHwYWSm1qDV1NBDPuPAaVmqqmzuHJ4NI45W8hRiYr/H74X0u+ywzfX3lx7B3F+Q+cUwdP6TnJkc7mThTpvz8ICWw6Uepbdxhg8syTGF1jO+2Bcxcq/cwU3VEYa60jywyGe/Fj70P0fD0SjhOAqIwTO/yWwtF6NuxP5JZM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=l2kHekMX; arc=none smtp.client-ip=209.85.216.41 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="l2kHekMX" Received: by mail-pj1-f41.google.com with SMTP id 98e67ed59e1d1-2c9a8313984so2870215a91.2 for ; Mon, 08 Jul 2024 15:16:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1720476971; x=1721081771; darn=vger.kernel.org; h=mime-version:user-agent:content-transfer-encoding:references :in-reply-to:date:cc:to:from:subject:message-id:from:to:cc:subject :date:message-id:reply-to; bh=h6vq6ownG6HIDtryCrk+PoGOueJGzfS405DNiCfiatc=; b=l2kHekMX8CG4759UA21FF5pkibV9g5Kf9OcKqxxRRR3rLW+PAL1O20B2mqNVxh6cyZ nELvpVy+GQzFwIEdE3MuXnsXjhDGeh3fXjsLSyYTJ5SFKRxkRzvcnnXPxXxX/i5W1Ge3 4Ha0Lh7OMXtbtqaYcL+v2GsRN26nSt6AfBLAU1fMJZzPChsmaGx/c0TKSNfGDspFpF9C S7xwzrILB4bGK7nAR6N2i3tfTocAlmDkvsYzZIOhQPhlOXofir3eXQuAJfTBJsX0mNql HOK6Umt2KwKdlMJOYuYit/0of3hSa5gFNgJq7hb5+LkfOC0z+emXa16AR05eIJbpcS7J TNMg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1720476971; x=1721081771; h=mime-version:user-agent:content-transfer-encoding:references :in-reply-to:date:cc:to:from:subject:message-id:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=h6vq6ownG6HIDtryCrk+PoGOueJGzfS405DNiCfiatc=; b=vXAG8kqwoVDVcSU8f9JzVTZDqmVpX+LQiZI+YoFIvFXCy6mV+1zlFD1p+V6rgPdXmR IS7imDLy9lnFb6e9bfZRCYG6VYzm2urU/ffEfTzmTMUPwzhGrojI7iVvS94h/32KBG2b tdeMsqi7mooHH22pmkppdXcJPZWWhlbJlJInNJ0NFUJS3oUXv7KSq97l8My2fI2hH4Ps arG+2IKPT60cq6mi4IE1/ODXTd0IdyGLQ6pINMsEIfRwVEAkcSmlvfCfZ2W1pLDQ4SRA /oc+tWtGH+TDB6DOlbqflrOLaDtl9+XQYrFzW8P/ZR5SPdHqogsFFefnlVHCHqmCUX97 TGDw== X-Forwarded-Encrypted: i=1; AJvYcCUqDqPyWNzv3kRStHqre2ZQo7831yHpRxFo1VCXF0mv+O0eIrqdU6u9ixVKDSAuQZxezaBQlsoIQU0kQOdk6OLRGvuN X-Gm-Message-State: AOJu0YxDurLrzllARnNWkxnV0Ruji604hN3aTATYxH4BsY+rnO4xolqt uIxmJgCFdlsP97dJsRMIT3xrWjFQskXeRTRrdyyDTQK4CbFotbNQ X-Google-Smtp-Source: AGHT+IEu8z1Lnqyq/4GSllnIRgMjgk86omlQObfsZMiYswf/hC0zq4hNVWiJ56RhOYxIRy9jYanUFQ== X-Received: by 2002:a17:90a:ca87:b0:2c9:7ae1:8f62 with SMTP id 98e67ed59e1d1-2ca35d599e0mr772985a91.46.1720476970839; Mon, 08 Jul 2024 15:16:10 -0700 (PDT) Received: from [192.168.0.31] ([38.34.87.7]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2c99aabab9dsm8657210a91.57.2024.07.08.15.16.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 08 Jul 2024 15:16:10 -0700 (PDT) Message-ID: <27f9c0ab24f06c4215f75fe12e05b26c24e43071.camel@gmail.com> Subject: Re: [PATCH v2 bpf-next 1/3] bpftool: improve skeleton backwards compat with old buggy libbpfs From: Eduard Zingerman To: Andrii Nakryiko , bpf@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net, martin.lau@kernel.org Cc: kernel-team@meta.com, Quentin Monnet , Mykyta Yatsenko Date: Mon, 08 Jul 2024 15:16:05 -0700 In-Reply-To: <20240708204540.4188946-2-andrii@kernel.org> References: <20240708204540.4188946-1-andrii@kernel.org> <20240708204540.4188946-2-andrii@kernel.org> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.44.4-0ubuntu2 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Mon, 2024-07-08 at 13:45 -0700, Andrii Nakryiko wrote: > Old versions of libbpf don't handle varying sizes of bpf_map_skeleton > struct correctly. As such, BPF skeleton generated by newest bpftool > might not be compatible with older libbpf (though only when libbpf is > used as a shared library), even though it, by design, should. >=20 > Going forward libbpf will be fixed, plus we'll release bug fixed > versions of relevant old libbpfs, but meanwhile try to mitigate from > bpftool side by conservatively assuming older and smaller definition of > bpf_map_skeleton, if possible. Meaning, if there are no struct_ops maps. >=20 > If there are struct_ops, then presumably user would like to have > auto-attaching logic and struct_ops map link placeholders, so use the > full bpf_map_skeleton definition in that case. >=20 > Acked-by: Quentin Monnet > Co-developed-by: Mykyta Yatsenko > Signed-off-by: Mykyta Yatsenko > Signed-off-by: Andrii Nakryiko > --- Acked-by: Eduard Zingerman