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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=HVwwGpgK; 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 E3EAD606A334; Tue, 3 Nov 2026 06:54:35 +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=HVwwGpgK Received: by smtp.kernel.org (Postfix) with ESMTPSA id 57D471F000C1; Tue, 3 Nov 2026 06:54:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793688875; bh=pI+R0vssS3+rBEwGlEmrhAJtAWwC+K6R2fL7Q2wxluc=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=HVwwGpgKph2PTCR3kNBpzgeJl9Fiv96ILTSVlqr7otzEN5KOe+3Oq36TZyy3FWiTn B5JC9rU3ADl82tq64bDRGFlV2NLyjhAO9fPnLejhbwzeG1Z9dc6ee0GVq9fDWJMr9G uEn9b1MhNhFVniqfmxfA0bqOs/QBhcC6kPjZ8hJFtdA34IHlyTNGGcCj68Y62ICtjk Ouq+kpEpWGx9PHR9MkFKZswgqiZXimSJHDR7+eldSuTYGotHgFLXgZCx0dKYEpIAcw 6pYXyTE/pVVs21IvMkWqyQ4k+6ZNZ7Rqbrs3FA5NB7/Klj97W0Huza14rR1CDkHC3E tLDaFtIRr3wRA== Message-ID: Date: Tue, 3 Nov 2026 07:54:21 +0100 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFC 19/23] tty: sysrq: let procfs copy in writes to /proc/sysrq-trigger To: Christian Brauner , 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, Chuck Lever References: <20261102-work-procfs-drivers-v1-0-a994bd4d3b1a@kernel.org> <20261102-work-procfs-drivers-v1-19-a994bd4d3b1a@kernel.org> Content-Language: en-US From: Jiri Slaby Autocrypt: addr=jirislaby@kernel.org; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 02. 11. 26, 16:07, Christian Brauner wrote: > Implement ->proc_write_buf() so procfs copies in what is written before > it pins the entry, and handle the keys from that copy. Writes larger > than PAGE_SIZE - 1 bytes fail with -EINVAL now. They used to trigger the > first key, or all of them in bulk mode. procfs allocates the copy, which > is as small as the write, opening the file allocated as much already. > > Signed-off-by: Christian Brauner (Amutable) Reviewed-by: Jiri Slaby > --- > drivers/tty/sysrq.c | 9 +++------ > 1 file changed, 3 insertions(+), 6 deletions(-) > > diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c > index f4571d05b496..99363e1b59ed 100644 > --- a/drivers/tty/sysrq.c > +++ b/drivers/tty/sysrq.c > @@ -1200,17 +1200,14 @@ EXPORT_SYMBOL(unregister_sysrq_key); > * However, if the first character is an underscore, > * all characters are processed. > */ > -static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf, > +static ssize_t write_sysrq_trigger(struct file *file, char *buf, > size_t count, loff_t *ppos) > { > bool bulk = false; > size_t i; > > for (i = 0; i < count; i++) { > - char c; > - > - if (get_user(c, buf + i)) > - return -EFAULT; > + char c = buf[i]; > > if (c == '_') > bulk = true; > @@ -1225,7 +1222,7 @@ static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf, > } > > static const struct proc_ops sysrq_trigger_proc_ops = { > - .proc_write = write_sysrq_trigger, > + .proc_write_buf = write_sysrq_trigger, > .proc_lseek = noop_llseek, > }; > > -- js suse labs