On Sat, Mar 30, 2019 at 06:43:11AM +0100, Greg Kroah-Hartman wrote:
On Fri, Mar 29, 2019 at 09:28:26PM -0400, Sasha Levin wrote:From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> [ Upstream commit 36991ca68db9dd43bac7f3519f080ee3939263ef ] If debugfs were to return a non-NULL error for a debugfs call, using that pointer later in debugfs_create_files() would crash. Fix that by properly checking the pointer before referencing it. Reported-by: Michal Hocko <mhocko@xxxxxxxxxx> Reported-and-tested-by: syzbot+b382ba6a802a3d242790@xxxxxxxxxxxxxxxxxxxxxxxxx Reported-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- block/blk-mq-debugfs.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c index cb1e6cf7ac48..9dc3a0896462 100644 --- a/block/blk-mq-debugfs.c +++ b/block/blk-mq-debugfs.c @@ -806,6 +806,9 @@ static const struct blk_mq_debugfs_attr blk_mq_debugfs_ctx_attrs[] = { static bool debugfs_create_files(struct dentry *parent, void *data, const struct blk_mq_debugfs_attr *attr) { + if (IS_ERR_OR_NULL(parent)) + return false; + d_inode(parent)->i_private = data; for (; attr->name; attr++) { -- 2.19.1This was a 5.0-only thing, no need for it to be backported anywhere. Please drop it from all of your trees.
Dropped, thanks. -- Thanks, Sasha
