From: Coly Li <colyli@suse.de> mainline inclusion from mainline-5.6-rc1 commit ae3cd299919af6eb670d5af0bc9d7ba14086bd8e category: feature bugzilla: 43003 CVE: NA --------------------------- The patch "bcache: rework error unwinding in register_bcache" introduces a use-after-free regression in register_bcache(). Here are current code, 2510 out_free_path: 2511 kfree(path); 2512 out_module_put: 2513 module_put(THIS_MODULE); 2514 out: 2515 pr_info("error %s: %s", path, err); 2516 return ret; If some error happens and the above code path is executed, at line 2511 path is released, but referenced at line 2515. Then KASAN reports a use- after-free error message. This patch changes line 2515 in the following way to fix the problem, 2515 pr_info("error %s: %s", path?path:"", err); Signed-off-by: Coly Li <colyli@suse.de> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk> Acked-by: Hanjun Guo <guohanjun@huawei.com> Reviewed-by: Yufen Yu <yuyufen@huawei.com> Signed-off-by: zhangyi (F) <yi.zhang@huawei.com> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- drivers/md/bcache/super.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c index a5bbaf0c047a..d0c19f9dcbdc 100644 --- a/drivers/md/bcache/super.c +++ b/drivers/md/bcache/super.c @@ -2470,10 +2470,11 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr, kfree(sb); out_free_path: kfree(path); + path = NULL; out_module_put: module_put(THIS_MODULE); out: - pr_info("error %s: %s", path, err); + pr_info("error %s: %s", path?path:"", err); return ret; } -- 2.25.1