lkml.org 
[lkml]   [2016]   [Nov]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] btrfs: fix uninitialized variable access after ASSERT
Date
In btrfs, ASSERT() has no effect if CONFIG_BTRFS_ASSERT is disabled,
and gcc notices that this can lead to using an uninitialized variable:

fs/btrfs/inode.c: In function 'run_delalloc_range':
fs/btrfs/inode.c:1190:18: error: 'cur_end' may be used uninitialized in this function [-Werror=maybe-uninitialized]

I assume the condition that the ASSERT checks for is actually
correct and we won't get there in practice, but it's easy to
modify the function to make it simpler and avoid the condition
that the warning is for.

Fixes: e5249f75cfd0 ("btrfs: Introduce COMPRESS reserve type to fix false enospc for compression")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
fs/btrfs/inode.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index e6f35d923d67..b1d2b38d29aa 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1175,18 +1175,14 @@ static int cow_file_range_async(struct inode *inode, struct page *locked_page,
clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
1, 0, NULL, GFP_NOFS);
while (start < end) {
+ ASSERT(reserve_type == BTRFS_RESERVE_COMPRESS);
async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
BUG_ON(!async_cow); /* -ENOMEM */
async_cow->inode = igrab(inode);
async_cow->root = root;
async_cow->locked_page = locked_page;
async_cow->start = start;
-
- if (reserve_type == BTRFS_RESERVE_COMPRESS)
- cur_end = min(end, start + SZ_512K - 1);
- else
- ASSERT(0);
-
+ cur_end = min(end, start + SZ_512K - 1);
async_cow->end = cur_end;
INIT_LIST_HEAD(&async_cow->extents);

--
2.9.0
\
 
 \ /
  Last update: 2016-11-28 22:07    [W:0.023 / U:0.144 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site