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Mon, 2 Nov 2026 15:23:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793633052; bh=0DA6RuBvRtTkFqswtNQb2uYlEiZpU59l9tIHU1Ga2j8=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=Wzv23e35LlF722Cfqg73FBGVnhxt+H5uTjMVTnB7asIIrTAol+UsSWODD3A9JMAWW CHeJx+/sOCjLZSq1s4VoynRxvWm7XhKnNjGUb4tFL3st5AhwGX1X8EXNyiNSob8zfe hPoA0Jwnc94AejcwzAl8mS34lOo0kwPJnFcg+lOSVQtUdf4OqaeMQYnXbxeWnmbXEb AX7yo9n+oT0VV5xUQw7x3ALW+dHnEd/WKJEInzk6ceYQfrGKcinK0xZJkLZt2jHfOm CKZoFbsH8Uf/vBc0GUbzhEZ6RBBP6OGx93Jv1yb/leud/4X919tLDeUZ9h/mDfqa8c 5djzkG/VTzWXw== From: Christian Brauner Date: Mon, 02 Nov 2026 16:07:23 +0100 Subject: [PATCH RFC 13/27] locking/lockdep: let procfs copy in writes to /proc/lock_stat 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" Content-Transfer-Encoding: 7bit Message-Id: <20261102-work-procfs-fs-v1-13-d09a996317b3@kernel.org> References: <20261102-work-procfs-fs-v1-0-d09a996317b3@kernel.org> In-Reply-To: <20261102-work-procfs-fs-v1-0-d09a996317b3@kernel.org> 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 X-Mailer: b4 0.17-dev X-Developer-Signature: v=1; a=openpgp-sha256; l=1505; i=brauner@kernel.org; h=from:subject:message-id; bh=8vcSfGoyDeqLJaquRqiN2D+SQsNeRK8HAS3H3FbecE8=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWS9WG6k0HtsppuIOtP74Igd108lcc3fGSuzcnJdKhtD4 so7t2c0dZSyMIhxMciKKbI4tJuEyy3nqdhslKkBM4eVCWQIAxenAExkkQEjQ+ONtmlOpu7yPdtO f6mefC2DpTVNKs/EavHuEoFe/ryYWEaGI5/jjbfc+3ttHUtbJafnBWsGE6vUrY4/vk118NKbYRj KAAA= X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 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 look at the first character of that copy. Writes larger than PAGE_SIZE - 1 bytes fail with -EINVAL now. Signed-off-by: Christian Brauner (Amutable) --- kernel/locking/lockdep_proc.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) diff --git a/kernel/locking/lockdep_proc.c b/kernel/locking/lockdep_proc.c index 9b034b5b94bd..2a66ea09c2aa 100644 --- a/kernel/locking/lockdep_proc.c +++ b/kernel/locking/lockdep_proc.c @@ -669,18 +669,14 @@ static int lock_stat_open(struct inode *inode, struct file *file) return 0; } -static ssize_t lock_stat_write(struct file *file, const char __user *buf, - size_t count, loff_t *ppos) +static ssize_t lock_stat_write(struct file *file, char *buf, size_t count, + loff_t *ppos) { struct lock_class *class; unsigned long idx; - char c; if (count) { - if (get_user(c, buf)) - return -EFAULT; - - if (c != '0') + if (buf[0] != '0') return count; iterate_lock_classes(idx, class) { @@ -703,7 +699,7 @@ static int lock_stat_release(struct inode *inode, struct file *file) static const struct proc_ops lock_stat_proc_ops = { .proc_seq_ops = &lockstat_ops, .proc_open = lock_stat_open, - .proc_write = lock_stat_write, + .proc_write_buf = lock_stat_write, .proc_release = lock_stat_release, }; #endif /* CONFIG_LOCK_STAT */ -- 2.53.0