From: Al Viro <viro@zeniv.linux.org.uk>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: linux-fsdevel@vger.kernel.org,
"J. Bruce Fields" <bfields@redhat.com>,
syzbot <syzbot+2c95195d5d433f6ed6cb@syzkaller.appspotmail.com>
Subject: Re: [PATCH] nfsd: fix dentry leak upon mkdir failure.
Date: Mon, 12 Aug 2019 04:03:54 +0100 [thread overview]
Message-ID: <20190812030354.GR1131@ZenIV.linux.org.uk> (raw)
In-Reply-To: <1565576171-6586-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp>
On Mon, Aug 12, 2019 at 11:16:11AM +0900, Tetsuo Handa wrote:
> syzbot is reporting that nfsd_mkdir() forgot to remove dentry created by
> d_alloc_name() when __nfsd_mkdir() failed (due to memory allocation fault
> injection) [1].
That's not the only problem I see there.
ret = __nfsd_mkdir(d_inode(parent), dentry, S_IFDIR | 0600);
if (ret)
goto out_err;
if (ncl) {
d_inode(dentry)->i_private = ncl;
kref_get(&ncl->cl_ref);
}
and we are doing that to inode *after* it has become visible via dcache -
__nfsd_mkdir() has already done d_add() (and pinged f-snotify, at that).
Looks fishy...
next prev parent reply other threads:[~2019-08-12 3:03 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-12 2:07 BUG: Dentry still in use [unmount of nfsd nfsd] syzbot
2019-08-12 2:16 ` [PATCH] nfsd: fix dentry leak upon mkdir failure Tetsuo Handa
2019-08-12 3:03 ` Al Viro [this message]
2019-08-15 20:23 ` J. Bruce Fields
2019-08-15 19:59 ` J. Bruce Fields
2019-08-15 20:53 ` Tetsuo Handa
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