From 4b788ca419ec37e4cdb421fef9edc208a491ce30 Mon Sep 17 00:00:00 2001 From: Mohit Aggarwal Date: Thu, 25 May 2017 20:21:12 +0530 Subject: [PATCH] diag: Synchronize command registration table access Currently, command registration table is being read in debugfs without any protection which may lead to access of stale entries. The patch takes care of the issue by adding proper protection. CRs-Fixed: 2032672 Bug: 63868628 Change-Id: I6ae058c16873f9ed52ae6516a1a70fd6d2d0da80 Signed-off-by: Mohit Aggarwal --- drivers/char/diag/diag_debugfs.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/char/diag/diag_debugfs.c b/drivers/char/diag/diag_debugfs.c index f5e4eba1e96bc..b66c8cb8257c2 100644 --- a/drivers/char/diag/diag_debugfs.c +++ b/drivers/char/diag/diag_debugfs.c @@ -1,4 +1,4 @@ -/* Copyright (c) 2011-2016, The Linux Foundation. All rights reserved. +/* Copyright (c) 2011-2017, The Linux Foundation. All rights reserved. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 and @@ -268,8 +268,10 @@ static ssize_t diag_dbgfs_read_table(struct file *file, char __user *ubuf, struct list_head *temp; struct diag_cmd_reg_t *item = NULL; + mutex_lock(&driver->cmd_reg_mutex); if (diag_dbgfs_table_index == driver->cmd_reg_count) { diag_dbgfs_table_index = 0; + mutex_unlock(&driver->cmd_reg_mutex); return 0; } @@ -278,6 +280,7 @@ static ssize_t diag_dbgfs_read_table(struct file *file, char __user *ubuf, buf = kzalloc(sizeof(char) * buf_size, GFP_KERNEL); if (ZERO_OR_NULL_PTR(buf)) { pr_err("diag: %s, Error allocating memory\n", __func__); + mutex_unlock(&driver->cmd_reg_mutex); return -ENOMEM; } buf_size = ksize(buf); @@ -322,6 +325,7 @@ static ssize_t diag_dbgfs_read_table(struct file *file, char __user *ubuf, break; } diag_dbgfs_table_index = i; + mutex_unlock(&driver->cmd_reg_mutex); *ppos = 0; ret = simple_read_from_buffer(ubuf, count, ppos, buf, bytes_in_buffer);