From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Martin Schwidefsky Subject: [PATCH 4.4 09/36] s390: TASK_SIZE for kernel threads Date: Mon, 13 Mar 2017 16:39:09 +0800 Message-Id: <20170313083353.039996693@linuxfoundation.org> In-Reply-To: <20170313083352.550085638@linuxfoundation.org> References: <20170313083352.550085638@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Martin Schwidefsky commit fb94a687d96c570d46332a4a890f1dcb7310e643 upstream. Return a sensible value if TASK_SIZE if called from a kernel thread. This gets us around an issue with copy_mount_options that does a magic size calculation "TASK_SIZE - (unsigned long)data" while in a kernel thread and data pointing to kernel space. Signed-off-by: Martin Schwidefsky Signed-off-by: Greg Kroah-Hartman --- arch/s390/include/asm/processor.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/arch/s390/include/asm/processor.h +++ b/arch/s390/include/asm/processor.h @@ -74,7 +74,8 @@ extern void execve_tail(void); * User space process size: 2GB for 31 bit, 4TB or 8PT for 64 bit. */ -#define TASK_SIZE_OF(tsk) ((tsk)->mm->context.asce_limit) +#define TASK_SIZE_OF(tsk) ((tsk)->mm ? \ + (tsk)->mm->context.asce_limit : TASK_MAX_SIZE) #define TASK_UNMAPPED_BASE (test_thread_flag(TIF_31BIT) ? \ (1UL << 30) : (1UL << 41)) #define TASK_SIZE TASK_SIZE_OF(current)