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Subject: Re: [PATCH 07/28] ceph: avoid false positive maybe-uninitialized
 warning
From: "Yan, Zheng" <zyan@redhat.com>
In-Reply-To: <20161017220903.1746743-1-arnd@arndb.de>
Date: Tue, 18 Oct 2016 10:07:45 +0800
Cc: Sage Weil <sage@redhat.com>, Ilya Dryomov <idryomov@gmail.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        open list <linux-kernel@vger.kernel.org>,
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        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Nikolay Borisov <n.borisov.lkml@gmail.com>,
        ceph-devel <ceph-devel@vger.kernel.org>
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 <20161017220903.1746743-1-arnd@arndb.de>
To: Arnd Bergmann <arnd@arndb.de>
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> On 18 Oct 2016, at 06:08, Arnd Bergmann <arnd@arndb.de> wrote:
> 
> A recent rework removed the initialization of the local 'root'
> variable that is returned from ceph_real_mount:
> 
> fs/ceph/super.c: In function 'ceph_mount':
> fs/ceph/super.c:1016:38: error: 'root' may be used uninitialized in this function [-Werror=maybe-uninitialized]
> 
> It's not obvious to me what the correct fix is, so this just
> returns the saved root as we did before.
> 
> Fixes: ce2728aaa82b ("ceph: avoid accessing / when mounting a subpath")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> Cc: "Yan, Zheng" <zyan@redhat.com>
> ---
> fs/ceph/super.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/ceph/super.c b/fs/ceph/super.c
> index a29ffce..79a4be8 100644
> --- a/fs/ceph/super.c
> +++ b/fs/ceph/super.c
> @@ -821,7 +821,8 @@ static struct dentry *ceph_real_mount(struct ceph_fs_client *fsc)
> 	dout("mount start %p\n", fsc);
> 	mutex_lock(&fsc->client->mount_mutex);
> 
> -	if (!fsc->sb->s_root) {
> +	root = dget(fsc->sb->s_root);
> +	if (!root) {
> 		const char *path;
> 		err = __ceph_open_session(fsc->client, started);
> 		if (err < 0)
> — 

This bug has already been fixed.

Regards
Yan, Zheng

> 2.9.0
>