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smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=EaJvHiAM; 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)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 64DCF6070F24; Wed, 4 Nov 2026 19:39:19 +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=EaJvHiAM Received: by smtp.kernel.org (Postfix) with ESMTPSA id C8DC61F000C1; Wed, 4 Nov 2026 19:39:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793821158; bh=08oqN1TE6XF/zda2aaIy/jJ7rzXSJoF5jY3Jq8EQn3I=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=EaJvHiAMOM44mJ4AYyNn4VsI9tCdPZkXSAVa50U3NrOibefU8zFHhtlwKggezxc6f wnraA02g8NJXIrS3SZrOw/ckLDW5FYvi7jxpCw0K00BYbn5RYhILqubA1RmFr09QV/ k8Ctg/JVPDQToSJB15j4p4jKQY0itLX/D67pNlmoINjEoJlweC93iKdvLzgAObEB/x Em9ifBMZxzKnjasz1lK0O58rkh4J6xzSeJOqNNv+26qOtx9ntPbRT5XujsHFDMwoNN HTnCPQ1IABzvSMZrUrPP3tBDAg5ZtkrqubTQztGluNNIqQgLtUfcYWfLXYTWYVi5vn yQ86hX5tNJ3+g== From: Christian Brauner To: linux-fsdevel@vger.kernel.org Cc: Linus Torvalds , Jann Horn , Josef Bacik , Chris Mason , Jeff Layton , NeilBrown , Eric Dumazet , Thomas Gleixner , Al Viro , Jonathan Corbet , Christoph Hellwig , Greg Kroah-Hartman , Joel Granados , Kees Cook , Jan Kara , Jan Kara , linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-acpi@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-s390@vger.kernel.org, linux-scsi@vger.kernel.org, linux-um@lists.infradead.org, linux-wireless@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, netdev@vger.kernel.org, ntfs3@lists.linux.dev, platform-driver-x86@vger.kernel.org, coreteam@netfilter.org, kexec@lists.infradead.org, linux-pci@vger.kernel.org, linux-sound@vger.kernel.org, netfilter-devel@vger.kernel.org, dri-devel@lists.freedesktop.org, ibm-acpi-devel@lists.sourceforge.net, jfs-discussion@lists.sourceforge.net, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-cifs@vger.kernel.org, linux-fbdev@vger.kernel.org, linux-hwmon@vger.kernel.org, linux-mm@kvack.org, linux-sh@vger.kernel.org, linux-usb@vger.kernel.org, samba-technical@lists.samba.org, sparclinux@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-doc@vger.kernel.org, linux-serial@vger.kernel.org, linux-atm-general@lists.sourceforge.net, Takashi Iwai , linux-input@vger.kernel.org, linux-raid@vger.kernel.org, linux-ext4@vger.kernel.org, linux-modules@vger.kernel.org, linux-debuggers@vger.kernel.org, "Christian Brauner (Amutable)" , Chuck Lever Subject: [PATCH RESEND v2 14/23] x86/mtrr: let procfs copy in writes to /proc/mtrr Date: Wed, 4 Nov 2026 20:39:04 +0100 Message-ID: <20261104-work-procfs-arch-v2-14-2aeb952c9597@kernel.org> In-Reply-To: <20261104-work-procfs-arch-v2-0-2aeb952c9597@kernel.org> References: <20261104-work-procfs-arch-v2-0-2aeb952c9597@kernel.org> X-Mailing-List: netdev@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" X-Mailer: b4 0.17-dev X-Developer-Signature: v=1; a=openpgp-sha256; l=1645; i=brauner@kernel.org; h=from:subject:message-id; bh=soK7T1bbUsg7MQd+qkvxTDp2+B/10GD8og0zR7/9Z5c=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWS97vgbYnk5w1TAv+cR/19mB87Hxr1yYY5rHB54MaZe7 z00yU+vo5SFQYyLQVZMkcWh3SRcbjlPxWajTA2YOaxMIEMYuDgFYCKfFzEyTOHm/S1/MZHxwIv8 7dtPVu6S3Lllwdu7ZYHrrz/Q+cjbY83IsGb+7VvZO/dOnXhuMvvjlQVn3RZfi/jDsjPicIm1t/+ HZBYA X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Content-Transfer-Encoding: 8bit Implement ->proc_write_buf() so procfs copies in what is written before it pins the entry, and parse the command from that copy. Writes larger than PAGE_SIZE - 1 bytes fail with -EINVAL now. Signed-off-by: Christian Brauner (Amutable) --- arch/x86/kernel/cpu/mtrr/if.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/arch/x86/kernel/cpu/mtrr/if.c b/arch/x86/kernel/cpu/mtrr/if.c index 9510e01d5103..038e2dc38797 100644 --- a/arch/x86/kernel/cpu/mtrr/if.c +++ b/arch/x86/kernel/cpu/mtrr/if.c @@ -91,7 +91,7 @@ mtrr_file_del(unsigned long base, unsigned long size, * "base=%Lx size=%Lx type=%s" or "disable=%d" */ static ssize_t -mtrr_write(struct file *file, const char __user *buf, size_t len, loff_t * ppos) +mtrr_write(struct file *file, char *buf, size_t len, loff_t * ppos) { int i, err; unsigned long reg; @@ -103,9 +103,8 @@ mtrr_write(struct file *file, const char __user *buf, size_t len, loff_t * ppos) memset(line, 0, LINE_SIZE); len = min_t(size_t, len, LINE_SIZE - 1); - length = strncpy_from_user(line, buf, len); - if (length < 0) - return length; + length = strnlen(buf, len); + memcpy(line, buf, length); ptr = line + length - 1; if (length && *ptr == '\n') @@ -397,7 +396,7 @@ static int mtrr_open(struct inode *inode, struct file *file) static const struct proc_ops mtrr_proc_ops = { .proc_show = mtrr_seq_show, .proc_open = mtrr_open, - .proc_write = mtrr_write, + .proc_write_buf = mtrr_write, .proc_ioctl = mtrr_ioctl, #ifdef CONFIG_COMPAT .proc_compat_ioctl = mtrr_ioctl, -- 2.53.0