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Wed, 4 Nov 2026 19:50:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793821820; bh=gDybWaXH0yVqSHGh6cSao1kY+huQ+XTPXQ1Vld4D+UM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ViWv5liEfHdMHPO8R1wapbcJqOA3zpGPpbB02hMT5/E0508nWx30DxqIPL6KtEmgU u+pmFn3FsOd19p4MgLsNq//oFD4EhVxfbRb3hFQDajUha4PG308MHKfbBxuQRI2T+1 gpfAFci1AHyTvujOOroEbIobGBHWkRbja9thyu+sIlV6GnLkbKj+7KO+0ZAH32xVH8 iBv7uhmdL2bAAOXVUHaVgSNDhqWBsAdgXyxjuxMQt4FvbC+ZMkyYx1jsvDEISH0f4o af3/XVxyIwOpd+kA2KJQBzwNtAgTJZ+nIEKqRvJiOre/ZrMnKSk9pNUZKOAQUsYWh4 hiwj+uPWiEFJg== 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 02/30] jfs: let procfs copy in writes to the loglevel file Date: Wed, 4 Nov 2026 20:50:06 +0100 Message-ID: <20261104-work-procfs-fs-v2-2-319e0f9a8aae@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-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=1370; i=brauner@kernel.org; h=from:subject:message-id; bh=izEZyN2ciF2azWBwOiarD7rxdH5SrLb74RUgxhmuQ3M=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWS97tGJzso6nn/w61mbive7Xqy3zX3zdMnSHJ2eBVw3m Q2DcmIjOkpZGMS4GGTFFFkc2k3C5ZbzVGw2ytSAmcPKBDKEgYtTACZyciEjw/nFJ7zrmRr3TTvN 7yT61kBSiuve9sV8G24zvhXijXX584zhr/RSZtXdspF7F/LOFVzmc/vt+qo5X9YsanqxkXF3yLP QUzwA X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Content-Transfer-Encoding: 8bit X-BeenThere: linux-um@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-um" X-Spam-Status: No, score=-18.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,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 level from that copy. Writes larger than PAGE_SIZE - 1 bytes fail with -EINVAL now and so do empty writes, which looked at a byte that wasn't written before. Signed-off-by: Christian Brauner (Amutable) --- fs/jfs/jfs_debug.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/fs/jfs/jfs_debug.c b/fs/jfs/jfs_debug.c index 5eb35b0d420f..e1c0211a6a32 100644 --- a/fs/jfs/jfs_debug.c +++ b/fs/jfs/jfs_debug.c @@ -23,13 +23,10 @@ static int jfs_loglevel_proc_show(struct seq_file *m, void *v) return 0; } -static ssize_t jfs_loglevel_proc_write(struct file *file, - const char __user *buffer, size_t count, loff_t *ppos) +static ssize_t jfs_loglevel_proc_write(struct file *file, char *buffer, + size_t count, loff_t *ppos) { - char c; - - if (get_user(c, buffer)) - return -EFAULT; + char c = buffer[0]; /* yes, I know this is an ASCIIism. --hch */ if (c < '0' || c > '9') @@ -40,7 +37,7 @@ static ssize_t jfs_loglevel_proc_write(struct file *file, static const struct proc_ops jfs_loglevel_proc_ops = { .proc_show = jfs_loglevel_proc_show, - .proc_write = jfs_loglevel_proc_write, + .proc_write_buf = jfs_loglevel_proc_write, }; #endif -- 2.53.0