From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794050082; b=UCQ7xNv+m/+paj4SPchCwvvyjFj+S7XzAsgAPEwQCoCWVMvcho0kyvssrHbfpAEt8mWj RPtvTTdffIkbQHQhhgMMp2BwYuOg5c/JRQt01k4LAmvxPokshjIRpsQ3e0xyrFVZp51Xf aEgEpZThnOHUDVsesrRicyDaINhI61dtSeGwMd9TfgWdM7spfTWd0YWRWovvADUj4TGTb gv1s1a30Pzjq9JxiQ4l4EpTM19WjU8ApqfgGFW7BqS3pOXGpd9CL8MqxWEqLZi7zifxtu ziRvrrG7j0IzExNK2Nr+09LMLDuuLY3oFFuGyBQIdxX61P8Vtf8kQhdgh0rSKZFv0DA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794050082; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=cNg010bqc43g/Ob8VN67mL/PiJKEZV8mHdcrP1RjRQE=; b=jXH1+AN+DraJzgblBYQdXlC1womYUm11vXOrAIcESdskZy0ZfzOEs9GWjM7VakfXdv/+ HK0px5ZQghdM/0llotCVK6+Owyhsy0J6QVeBpRDXX5mn6ltJ6bxbRPkJGwT/FjftdWH5P IOM9mrzEBECwSjDdloc5XOr114iVyPDTQLn987eSVbSL7hKIWkdaj+cdIwXM5mV33TEk8 F7pIlfcYajszol6mIRnvQ4B12badEf73g1H67EqYd84vk4QZZIg6dUuH0dxeY+GRQe6If q0ljk5e+i37XG3BZ8rwzFV0uV1T9VuHLRfko+HLu4+pgjqWVK3QzMyLOJNu0lQCVr0w== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=b9oEruBD; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 44406606A32C for ; Sat, 7 Nov 2026 11:14:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=b9oEruBD Received: by smtp.kernel.org (Postfix) with ESMTPSA id 89CBF1F0089F; Sat, 7 Nov 2026 11:14:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794050082; bh=cNg010bqc43g/Ob8VN67mL/PiJKEZV8mHdcrP1RjRQE=; h=From:To:Cc:Subject:Date; b=b9oEruBDrz3KrnPPfTj8ftRWBfT+lzCI5YFG9tO+GR7Q4a/T8pdrR4w5rVYLJUJzC fIQW+p2dV7qljekWi5r8xWNKvem0xVR8+MId+oNUweMNBZkrOW65IIaK9uWFdEt0Ln ICvXMX9ds5FEeLl/aePmrVNVdDds9sU7mW0qAj3qwEZLTgrahlsc2q5291InUdK6E6 NI1HsG2n6NleX1XMHiz7RajrfOcRF/E17ApUjMN0F2O+QK+d1Wr+E0gg8g94/eBRtK ADp1RwFWmha8OYxLhvy6+RypqjVuwJrvXwNXIBfptjKQVAeE2W7rAC0nLIW8YWx41E aKNz33AlWqv3w== From: Sasha Levin To: amir73il@gmail.com, 4ncienth@gmail.com, jack@suse.cz, brauner@kernel.org Cc: stable@vger.kernel.org Subject: FAILED: patch "[PATCH] fs: make sure to call fsnotify_inoderemove() only once when inode is dead" failed to apply to 5.10-stable tree Date: Sat, 7 Nov 2026 06:14:40 -0500 Message-ID: <20261107061440-failed-5.10-669bb5af15d4@kernel.org> X-Mailer: git-send-email 2.53.0 X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x 669bb5af15d41a21359d00a441490f87a88eb52a # git commit -s git send-email --to '' --in-reply-to '20261107061440-failed-5.10-669bb5af15d4@kernel.org' --subject-prefix 'PATCH 5.10.y' 'HEAD^..' Thanks, Sasha ------------------ original commit in Linus's tree ------------------ >From 669bb5af15d41a21359d00a441490f87a88eb52a Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Wed, 2 Sep 2026 18:49:25 +0200 Subject: [PATCH] fs: make sure to call fsnotify_inoderemove() only once when inode is dead Daehyeon reported a race wherein fsnotify_removeinode() can be called when inode still has a live alias. This can lead to several undesired outcomes such as crashes in fsnotify code or avoidance of inode mark notifications. Check that inode is really "dead", meaning no nlink and no more aliases before calling fsnotify_inoderemove() for final cleanup of inode marks. Also do not allow open_by_handle() to add new aliases to a "dead" inode. Ideally, we'd call fsnotify_inoderemove() once last inode reference is dropped to make things simpler. Alas fsnotify inode marks currently hold inode references and thus this doesn't work. Once we teach fsnotify to avoid holding inode references, these games with dead inodes can go as well. Reported-and-tested-by: Daehyeon Ko <4ncienth@gmail.com> Closes: https://lore.kernel.org/linux-fsdevel/20260827045007.3831259-1-4ncienth@gmail.com/ CC: stable@vger.kernel.org Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara Link: https://patch.msgid.link/20260902164924.1333135-2-jack@suse.cz Signed-off-by: Christian Brauner (Amutable) --- fs/dcache.c | 27 ++++++++++++++++++++++++--- 1 file changed, 24 insertions(+), 3 deletions(-) diff --git a/fs/dcache.c b/fs/dcache.c index 1b1a81f10da67..8f17db2724b38 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -450,6 +450,17 @@ static void dentry_free(struct dentry *dentry) call_rcu(&dentry->d_rcu, __d_free); } +/* + * If inode is unlinked and doesn't have any aliases (i.e., all fds pointing to + * it are closed), it is pretty much dead. Except that file handle lookup could + * still revive it which causes issues to fsnotify. So once inode reaches this + * state we make sure to block creating any new aliases. + */ +static bool inode_notify_dead(struct inode *inode) +{ + return !inode->i_nlink && hlist_empty(&inode->i_dentry); +} + /* * Release the dentry's inode, using the filesystem * d_iput() operation if defined. @@ -459,6 +470,7 @@ static void dentry_unlink_inode(struct dentry * dentry) __releases(dentry->d_inode->i_lock) { struct inode *inode = dentry->d_inode; + bool notify_dead; raw_write_seqcount_begin(&dentry->d_seq); __d_clear_type_and_inode(dentry); @@ -469,9 +481,10 @@ static void dentry_unlink_inode(struct dentry * dentry) */ dentry->waiters = NULL; raw_write_seqcount_end(&dentry->d_seq); + notify_dead = inode_notify_dead(inode); spin_unlock(&dentry->d_lock); spin_unlock(&inode->i_lock); - if (!inode->i_nlink) + if (notify_dead) fsnotify_inoderemove(inode); if (dentry->d_op && dentry->d_op->d_iput) dentry->d_op->d_iput(dentry, inode); @@ -2237,7 +2250,12 @@ static struct dentry *__d_obtain_alias(struct inode *inode, bool disconnected) sb = inode->i_sb; - res = d_find_any_alias(inode); /* existing alias? */ + spin_lock(&inode->i_lock); + if (!inode_notify_dead(inode)) + res = __d_find_any_alias(inode); /* existing alias? */ + else + res = ERR_PTR(-ESTALE); + spin_unlock(&inode->i_lock); if (res) goto out; @@ -2249,7 +2267,10 @@ static struct dentry *__d_obtain_alias(struct inode *inode, bool disconnected) security_d_instantiate(new, inode); spin_lock(&inode->i_lock); - res = __d_find_any_alias(inode); /* recheck under lock */ + if (!inode_notify_dead(inode)) + res = __d_find_any_alias(inode); /* recheck under lock */ + else + res = ERR_PTR(-ESTALE); if (likely(!res)) { /* still no alias, attach a disconnected dentry */ unsigned add_flags = d_flags_for_inode(inode); -- 2.53.0