All of lore.kernel.org
 help / color / mirror / Atom feed
From: "J. R. Okajima" <hooanon05g@gmail.com>
To: neilb@suse.de, trond.myklebust@hammerspace.com
Cc: linux-nfs@vger.kernel.org
Subject: NFS, two d_delete() calls in nfs_unlink()
Date: Wed, 17 Aug 2022 18:29:24 +0900	[thread overview]
Message-ID: <7634.1660728564@jrobl> (raw)

Hello NeilBrown and Trond Myklebust,

By the commin in v6.0-rc1,
	3c59366c207e 2022-08-08 NFS: don't unhash dentry during unlink/rename
nfs_unlink() stopped calling __d_drop().
And it MAY cause two d_delete() calls. If it happens, the second call
leads to NULL pointer access because d_inode is already cleared.

Here is the detail.

nfs_unlink()
+ nfs_safe_remove()
  + NFS_PROTO(dir)->remove() <-- returns ENOENT
  + nfs_dentry_handle_enoent()
    + if (simple_positive()) d_delete() <-- 1st call and d_inode is cleared
+ nfs_dentry_remove_handle_error()
  + if (ENOENT) d_delete() <-- second call and NULL d_inode is accessed

How about adding a condition for d_delete() call in
nfs_dentry_remove_handle_error(), such like simple_positive()?


J. R. Okajima

             reply	other threads:[~2022-08-17  9:29 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-17  9:29 J. R. Okajima [this message]
2022-08-18  2:55 ` NFS, two d_delete() calls in nfs_unlink() NeilBrown
2022-08-18  3:31   ` hooanon05g
2022-08-18 18:38     ` Olga Kornievskaia
2022-08-18 23:05     ` NeilBrown
2022-08-18 23:23       ` Trond Myklebust

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=7634.1660728564@jrobl \
    --to=hooanon05g@gmail.com \
    --cc=linux-nfs@vger.kernel.org \
    --cc=neilb@suse.de \
    --cc=trond.myklebust@hammerspace.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.