From: piaojun <piaojun@huawei.com>
To: "akpm@linux-foundation.org" <akpm@linux-foundation.org>,
<ericvh@gmail.com>, <rminnich@sandia.gov>, <lucho@ionkov.net>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
<v9fs-developer@lists.sourceforge.net>,
Jiangyiwen <jiangyiwen@huawei.com>
Subject: [PATCH] net/9p/client.c: put refcount of trans_mod in error case in parse_opts()
Date: Fri, 6 Jul 2018 17:42:56 +0800 [thread overview]
Message-ID: <5B3F39A0.2030509@huawei.com> (raw)
From my test, 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.
Fixes: 9421c3e64137ec ("net/9p/client.c: fix potential refcnt problem of trans module")
Signed-off-by: Jun Piao <piaojun@huawei.com>
---
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 18c5271..5c13431 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;
}
--
next reply other threads:[~2018-07-06 9:43 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-06 9:42 piaojun [this message]
2018-07-06 9:48 ` [PATCH] net/9p/client.c: put refcount of trans_mod in error case in parse_opts() jiangyiwen
2018-07-09 14:29 ` [V9fs-developer] " Greg Kurz
2018-07-11 5:47 ` Dominique Martinet
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