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b=L4z066t7qk8SNBZ3qr8F1Dv4FM+zeL5UMqbVPpZhgdQRsqgneSAYM0s8mSty+AN6F uOpJwVDXNMcIMJN/l4FNHGQgvK/QCR0cqApE4XNvTdD9heJSFssRxRma5MIWbLp5q7 KuStqfVc5Mi7/uCEtKU/XidV25HekngkokdSavKrGmFA9IR6yxAQ/fT2R/UVEXUpOV JshYWFM1jRBiauogMI9LETcKUpSEg7rlt/XCrsDvHcIcKKrKf+Lfu9grpGXEUlOUBw il1cziT3er+LG8IbGUfsHyBhUl9fEmWujhzvys7fEbuJMHuqJFLv3DIRlBTxlslyyu 1lR419jEJXKMw== 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 , stable@vger.kernel.org Subject: [PATCH v2 17/51] s390/dasd: don't look in front of the buffer on an empty write Date: Wed, 4 Nov 2026 18:47:03 +0100 Message-ID: <20261104-work-procfs-bugfixes-v2-17-bbf7d5546809@kernel.org> In-Reply-To: <20261104-work-procfs-bugfixes-v2-0-bbf7d5546809@kernel.org> References: <20261104-work-procfs-bugfixes-v2-0-bbf7d5546809@kernel.org> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; 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For an empty write that's the byte in front of the buffer it just allocated. Only look if something was written. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Christian Brauner (Amutable) --- drivers/s390/block/dasd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c index 2ffe404b890f..e97891e58957 100644 --- a/drivers/s390/block/dasd.c +++ b/drivers/s390/block/dasd.c @@ -933,7 +933,7 @@ char *dasd_get_user_string(const char __user *user_buf, size_t user_len) return ERR_PTR(-EFAULT); } /* got the string, now strip linefeed. */ - if (buffer[user_len - 1] == '\n') + if (user_len && buffer[user_len - 1] == '\n') buffer[user_len - 1] = 0; else buffer[user_len] = 0; -- 2.53.0