From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 EB3DB398FBA for ; Fri, 5 Dec 2025 01:18:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764897512; cv=none; b=XkY54XhrD3zPe4nYQxtx1aqDT+nSCCNrT5nQMhJCtcOsa8/z7uqL0f/lPmLD3xpgNYm/Rvpd3Df8wXdK+7iGMhz7nru1b9pDzX+RBn/JNg1cDRy1daV2zUmzujpVi/cbuZPtagVn/AZWNhhU6mH4yHDVFLYUh45LsUR4u9sfTLg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764897512; c=relaxed/simple; bh=gvSG0jtaY7/heFm/Gslk7vydXL6gPfvO6FWJa0v/rGs=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=BN7cSCK02Q/2fFf6PEZRmuuc8rHS1+hT8mr9W5Xe2QAg1hzN7pSAQMT+80iT3EWE1HSFLpdcqchqjqHTwPIEoLuPFARnBtJWXtsjyKtf7XaFFY5Lmhlmp97fXyUEA+JjyVaRoexnk5/Kj1EHmyXHeGncLdMXdf71bTvgomKEweo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=R8B4iJch; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="R8B4iJch" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B91FEC4CEFB; Fri, 5 Dec 2025 01:18:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1764897511; bh=gvSG0jtaY7/heFm/Gslk7vydXL6gPfvO6FWJa0v/rGs=; h=From:To:Cc:Subject:Date:From; b=R8B4iJchtdM9LB9bMtZ0wI0yjT3z8kLfdE/xEXXtJgqNKF8t9GiOfKWQpYLjN3TTy RTfmKdYaUTWB5Gi6okRasqiRrMo4r1LN5O+lmaqR00y5gvHK/6KTMlbnaAsrgYIcRH 7/gLLN6kaH+Je0FdfCJ6tuyIusAdUo1a0C/FMP7ftome/06bzEyvTt/xZPbEhmKnFH wSu7FlpjWt8TXakDfI1UZ2ILaVLozhahWzyUCTq2j3JUpZT6LGj5Gu9i5B/GKhrOnO vS8Eq823AtpUxbQzPCwwmtbrTApcT3/b3jr+rVhhgRkmY+JbtAjsW5eRP6to1J8uZ6 jFJouSTSJMSQg== From: Jakub Kicinski To: bpf@vger.kernel.org Cc: Jakub Kicinski , qmo@kernel.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, jolsa@kernel.org Subject: [PATCH bpf] tools: bpftool: fix truncated netlink dumps Date: Thu, 4 Dec 2025 17:18:23 -0800 Message-ID: <20251205011823.751868-1-kuba@kernel.org> X-Mailer: git-send-email 2.52.0 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Netlink requires that the recv buffer used during dumps is at least min(PAGE_SIZE, 8k) (see the man page). Otherwise the messages will get truncated. Make sure bpftool follows this requirement, avoid missing information on systems with large pages. Fixes: 7084566a236f ("tools/bpftool: Remove libbpf_internal.h usage in bpftool") Signed-off-by: Jakub Kicinski --- CC: qmo@kernel.org CC: ast@kernel.org CC: daniel@iogearbox.net CC: andrii@kernel.org CC: martin.lau@linux.dev CC: eddyz87@gmail.com CC: song@kernel.org CC: yonghong.song@linux.dev CC: john.fastabend@gmail.com CC: kpsingh@kernel.org CC: sdf@fomichev.me CC: haoluo@google.com CC: jolsa@kernel.org CC: bpf@vger.kernel.org --- tools/bpf/bpftool/net.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/tools/bpf/bpftool/net.c b/tools/bpf/bpftool/net.c index cfc6f944f7c3..7f248fc01332 100644 --- a/tools/bpf/bpftool/net.c +++ b/tools/bpf/bpftool/net.c @@ -156,7 +156,7 @@ static int netlink_recv(int sock, __u32 nl_pid, __u32 seq, bool multipart = true; struct nlmsgerr *err; struct nlmsghdr *nh; - char buf[4096]; + char buf[8192]; int len, ret; while (multipart) { @@ -201,6 +201,10 @@ static int netlink_recv(int sock, __u32 nl_pid, __u32 seq, return ret; } } + + if (len) + fprintf(stderr, "Invalid message or trailing data in Netlink response: %d\n", + len); } ret = 0; done: -- 2.52.0