From c290fba8c4ce6530cd941ea14db5a4ac2f77183f Mon Sep 17 00:00:00 2001 From: piaojun Date: Fri, 13 Jul 2018 16:59:06 -0700 Subject: [PATCH] net/9p/client.c: put refcount of trans_mod in error case in parse_opts() In my testing, the second mount will fail after umounting successfully. The reason is that we put refcount of trans_mod in the correct case rather than the error case in parse_opts() at last. That will cause the refcount decrease to -1, and when we try to get trans_mod again in try_module_get(), we could only increase refcount to 0 which will cause failure as follows: parse_opts v9fs_get_trans_by_name try_module_get : return NULL to caller which cause error So we should put refcount of trans_mod in error case. Link: http://lkml.kernel.org/r/5B3F39A0.2030509@huawei.com Fixes: 9421c3e64137ec ("net/9p/client.c: fix potential refcnt problem of trans module") Signed-off-by: Jun Piao Reviewed-by: Yiwen Jiang Reviewed-by: Greg Kurz Reviewed-by: Dominique Martinet Tested-by: Dominique Martinet Cc: Eric Van Hensbergen Cc: Ron Minnich Cc: Latchesar Ionkov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- net/9p/client.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/9p/client.c b/net/9p/client.c index 18c5271910dc..5c1343195292 100644 --- a/net/9p/client.c +++ b/net/9p/client.c @@ -225,7 +225,8 @@ static int parse_opts(char *opts, struct p9_client *clnt) } free_and_return: - v9fs_put_trans(clnt->trans_mod); + if (ret) + v9fs_put_trans(clnt->trans_mod); kfree(tmp_options); return ret; }