From patchwork Thu Oct 17 15:24:19 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Antoine Tenart X-Patchwork-Id: 13840226 X-Patchwork-Delegate: kuba@kernel.org 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 C9D421DEFD2 for ; Thu, 17 Oct 2024 15:24:34 +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=1729178674; cv=none; b=PdQNGym+Oi1kbW1ha8yjN6BlbxyzjgKF6UHpeUbrxXZEvUxnEYtrvx3CCe1rmdBCocZiBSiPgKM/d/OokTwrMgg//ApYgR4GG+Gqq9QJQhLmn0rhbJ8099NHXJEiXfiSfFVh5clsYOjq3+GltMDZAIKeT7odrgFC7ru83Vbtfv8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729178674; c=relaxed/simple; bh=Bb+72Sy2zMBwPYXqRH2QU/V370T/6jS4805nMXZEIAw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=eL88kJ8fFVm/j9zSzqOFtYPHb/y3FdKvQ6Z0kfftoykNUlboge56PEekhmsAiXiFQ43UbpVs+fWbrDxbi617ZXlXpcbc9KEObX6C4Dkztt3VfDG44n4fjLh9v/XMyc13EQIAVLChACYYxKiFCjnCjTdDnjd0jWGM7WndHrkhD8w= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=J8d/GOt/; 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="J8d/GOt/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 056ABC4CEC3; Thu, 17 Oct 2024 15:24:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1729178674; bh=Bb+72Sy2zMBwPYXqRH2QU/V370T/6jS4805nMXZEIAw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=J8d/GOt/R+2jirYIgCOBd2ZyvTM8QMC587spTQGMR1kI1rfsS4JkHiZ2ZJgnowQIt ewAaG7wFkjfjGm7GzApZ9bNYTnHrXOQgzUtxZ2ijDKFYUsGuKFDdu9Lk0ASHE01v3U J2cySFGzavavGvIylffcPXo+50nuRdjfOoO/fJV/TpXv2dq0+j3y+WuHk7e55liqK7 Syc+34oJfw1iQl3Re9OrOI8vUBy9/JW1qXHfNQM0Yy07al6J15jy0/E9kx+A9zbYS7 EbrhlR/SjGo4muRAvWDslkfFa86N+T2y9qzWNcIdtJA3eB9UdeRg35z5FYi89QZOMQ QHLGfSQDXPAwQ== From: Antoine Tenart To: davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com, edumazet@google.com Cc: Antoine Tenart , netdev@vger.kernel.org Subject: [PATCH net-next 3/3] net: sysctl: allow dump_cpumask to handle higher numbers of CPUs Date: Thu, 17 Oct 2024 17:24:19 +0200 Message-ID: <20241017152422.487406-4-atenart@kernel.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241017152422.487406-1-atenart@kernel.org> References: <20241017152422.487406-1-atenart@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org This fixes the output of rps_default_mask and flow_limit_cpu_bitmap when the CPU count is > 448, as it was truncated. The underlying values are actually stored correctly when writing to these sysctl but displaying them uses a fixed length temporary buffer in dump_cpumask. This buffer can be too small if the CPU count is > 448. Fix this by dynamically allocating the buffer in dump_cpumask, using a guesstimate of what we need. Signed-off-by: Antoine Tenart Reviewed-by: Simon Horman Reviewed-by: Simon Horman --- net/core/sysctl_net_core.c | 32 +++++++++++++++++++++++--------- 1 file changed, 23 insertions(+), 9 deletions(-) diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c index 8dc07f7b1772..cb8d32e5c14e 100644 --- a/net/core/sysctl_net_core.c +++ b/net/core/sysctl_net_core.c @@ -51,22 +51,32 @@ int sysctl_devconf_inherit_init_net __read_mostly; EXPORT_SYMBOL(sysctl_devconf_inherit_init_net); #if IS_ENABLED(CONFIG_NET_FLOW_LIMIT) || IS_ENABLED(CONFIG_RPS) -static void dump_cpumask(void *buffer, size_t *lenp, loff_t *ppos, - struct cpumask *mask) +static int dump_cpumask(void *buffer, size_t *lenp, loff_t *ppos, + struct cpumask *mask) { - char kbuf[128]; + char *kbuf; int len; if (*ppos || !*lenp) { *lenp = 0; - return; + return 0; + } + + /* CPUs are displayed as a hex bitmap + a comma between each groups of 8 + * nibbles (except the last one which has a newline instead). + * Guesstimate the buffer size at the group granularity level. + */ + len = min(DIV_ROUND_UP(nr_cpumask_bits, 32) * (8 + 1), *lenp); + kbuf = kmalloc(len, GFP_KERNEL); + if (!kbuf) { + *lenp = 0; + return -ENOMEM; } - len = min(sizeof(kbuf), *lenp); len = scnprintf(kbuf, len, "%*pb", cpumask_pr_args(mask)); if (!len) { *lenp = 0; - return; + goto free_buf; } /* scnprintf writes a trailing null char not counted in the returned @@ -76,6 +86,10 @@ static void dump_cpumask(void *buffer, size_t *lenp, loff_t *ppos, memcpy(buffer, kbuf, len); *lenp = len; *ppos += len; + +free_buf: + kfree(kbuf); + return 0; } #endif @@ -119,8 +133,8 @@ static int rps_default_mask_sysctl(const struct ctl_table *table, int write, if (err) goto done; } else { - dump_cpumask(buffer, lenp, ppos, - net->core.rps_default_mask ? : cpu_none_mask); + err = dump_cpumask(buffer, lenp, ppos, + net->core.rps_default_mask ? : cpu_none_mask); } done: @@ -249,7 +263,7 @@ static int flow_limit_cpu_sysctl(const struct ctl_table *table, int write, } rcu_read_unlock(); - dump_cpumask(buffer, lenp, ppos, mask); + ret = dump_cpumask(buffer, lenp, ppos, mask); } done: