4.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yunlei He <heyunlei@xxxxxxxxxx> commit 7855eba4d6102f811b6dd142d6c749f53b591fa3 upstream. This patch fix a problem of using memory after free in function __try_merge_extent_node. Fixes: 0f825ee6e873 ("f2fs: add new interfaces for extent tree") Signed-off-by: Yunlei He <heyunlei@xxxxxxxxxx> Reviewed-by: Chao Yu <yuchao0@xxxxxxxxxx> Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/f2fs/extent_cache.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/fs/f2fs/extent_cache.c +++ b/fs/f2fs/extent_cache.c @@ -352,11 +352,12 @@ static struct extent_node *__try_merge_e } if (next_ex && __is_front_mergeable(ei, &next_ex->ei)) { - if (en) - __release_extent_node(sbi, et, prev_ex); next_ex->ei.fofs = ei->fofs; next_ex->ei.blk = ei->blk; next_ex->ei.len += ei->len; + if (en) + __release_extent_node(sbi, et, prev_ex); + en = next_ex; }