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Wed, 4 Nov 2026 19:53:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793822001; bh=4FMH8RRbXwyOGE4j1ACekL014/FVLGRJa3NjwiBwv4k=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=gqnu7WCank0HPKzxIIuR0c+Y7qFDIfOx4OhXQRsH+bwXeorJsZ7tfbWZNyh3GbhMt NxTOPufkaHrp11YLfNa93/yXQ6n5h0z6fpBeg6Ly2XOx7LhglEYilynsq/HFu5e5m3 ATdWLZ7uW1x0Y8xMKxBVUpJaU7+YU0ZruYzah//QhnYRcr/O7neJgjfCiw3cbGeL0f /scHMQ7wD59wgQWjLWITDYTvE8W4dpcfUNiJQWmwj5fEXCsq8JXV17jYeqe34cF0gX jLq6ATZZOpXLQz2og6LqAuxsn4M17sNhw8oW2RQKUyiL2Rz59/u2T2Au+Zeqcz04DQ gpufF/LrdsChg== 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 14/30] profiling: let procfs copy in writes to /proc/profile Date: Wed, 4 Nov 2026 20:53:06 +0100 Message-ID: <20261104-work-procfs-fs-v2-14-319e0f9a8aae@kernel.org> In-Reply-To: <20261104-work-procfs-fs-v2-0-319e0f9a8aae@kernel.org> References: <20261104-work-procfs-fs-v2-0-319e0f9a8aae@kernel.org> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , Precedence: list X-Archived-By: 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=1504; i=brauner@kernel.org; h=from:subject:message-id; bh=acPYXqQQVYOg2sB+M+GQAGt+iBO20XAT2Sfl3M0drAc=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWS97rHOf25YKDbxbO9Bg6IFQW80Jrk2dVu9Wx+89J/Uj +nLeu/rdpSyMIhxMciKKbI4tJuEyy3nqdhslKkBM4eVCWQIAxenAEykIZiRYcq1Of62b8t3Tr08 3yy0w/fMvbrULi7+T2u03cst/b77X2BkOMOyo3gzb8Wco9XFOhk9DzgWqprLqslOEzaU3DZxl4A KIwA= X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 Implement ->proc_write_buf() so procfs copies in what is written before it pins the entry, and take the multiplier from that copy. Writes larger than PAGE_SIZE - 1 bytes fail with -EINVAL now. Signed-off-by: Christian Brauner (Amutable) --- kernel/profile.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/kernel/profile.c b/kernel/profile.c index 820d5ec909d4..dc2db66a77d2 100644 --- a/kernel/profile.c +++ b/kernel/profile.c @@ -189,16 +189,14 @@ int __weak setup_profiling_timer(unsigned mult) * Writing a 'profiling multiplier' value into it also re-sets the profiling * interrupt frequency, on architectures that support this. */ -static ssize_t write_profile(struct file *file, const char __user *buf, - size_t count, loff_t *ppos) +static ssize_t write_profile(struct file *file, char *buf, size_t count, + loff_t *ppos) { #ifdef CONFIG_SMP if (count == sizeof(int)) { unsigned int multiplier; - if (copy_from_user(&multiplier, buf, sizeof(int))) - return -EFAULT; - + memcpy(&multiplier, buf, sizeof(int)); if (setup_profiling_timer(multiplier)) return -EINVAL; } @@ -209,7 +207,7 @@ static ssize_t write_profile(struct file *file, const char __user *buf, static const struct proc_ops profile_proc_ops = { .proc_read = read_profile, - .proc_write = write_profile, + .proc_write_buf = write_profile, .proc_lseek = default_llseek, }; -- 2.53.0