From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1B5C4376BD3; Tue, 6 Jan 2026 17:59:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767722395; cv=none; b=O+wzrSOnlNuFn59L+c4T0rqjlLp1RG7Nl5MVxn81BujMj6YLBKjCUUymRGVYILv2nExSj7nwr3yppEZId0Mv2qpg4ragESy/mdYSNLC9Y7UawW5PkGfGx7uCVLLgzmvMNza5PGp3odw8AygPAqBAHtDOXytGw906x/j+Rxoa3jI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767722395; c=relaxed/simple; bh=724lZXmaHDp0+o68yJu+33hnDFFg7smiD1rxxX0rCyA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=l+NH+oi4ZLv+mgwONFLUX/8vSx+dtYXCNW9uv6pPOtjdhOYTQnjtghrBEM6Yg8YZhJrnG8utziNUvF38L4hHgUeNTSSa4GO6LSC1XNsZO3eXnns1p3jwv5IfuJOQMVBnqoupvyR8e1GqUer7fgaPivBUSOOcnYJouXcy5hRH1gk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Au1BlfSI; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Au1BlfSI" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7EB03C19423; Tue, 6 Jan 2026 17:59:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1767722395; bh=724lZXmaHDp0+o68yJu+33hnDFFg7smiD1rxxX0rCyA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Au1BlfSI3nGPYukQ46Uf92dFXpo+H4aSchSYyy633Baz/nwdjyBzLqwOv5fweh3CP Q3rrLtApTAafKgEml2NXM5jx+zDPStAuNsDtcyMwC5QkhWyXqsm4FBvY8YvN0dHHRv /yv2tjscmP9aYdszkR1Vzi2s31CkxXGkBCkdk0gY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jeff Layton , Chuck Lever Subject: [PATCH 6.18 251/312] nfsd: fix nfsd_file reference leak in nfsd4_add_rdaccess_to_wrdeleg() Date: Tue, 6 Jan 2026 18:05:25 +0100 Message-ID: <20260106170556.929269283@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260106170547.832845344@linuxfoundation.org> References: <20260106170547.832845344@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chuck Lever commit 8072e34e1387d03102b788677d491e2bcceef6f5 upstream. nfsd4_add_rdaccess_to_wrdeleg() unconditionally overwrites fp->fi_fds[O_RDONLY] with a newly acquired nfsd_file. However, if the client already has a SHARE_ACCESS_READ open from a previous OPEN operation, this action overwrites the existing pointer without releasing its reference, orphaning the previous reference. Additionally, the function originally stored the same nfsd_file pointer in both fp->fi_fds[O_RDONLY] and fp->fi_rdeleg_file with only a single reference. When put_deleg_file() runs, it clears fi_rdeleg_file and calls nfs4_file_put_access() to release the file. However, nfs4_file_put_access() only releases fi_fds[O_RDONLY] when the fi_access[O_RDONLY] counter drops to zero. If another READ open exists on the file, the counter remains elevated and the nfsd_file reference from the delegation is never released. This potentially causes open conflicts on that file. Then, on server shutdown, these leaks cause __nfsd_file_cache_purge() to encounter files with an elevated reference count that cannot be cleaned up, ultimately triggering a BUG() in kmem_cache_destroy() because there are still nfsd_file objects allocated in that cache. Fixes: e7a8ebc305f2 ("NFSD: Offer write delegation for OPEN with OPEN4_SHARE_ACCESS_WRITE") Cc: stable@vger.kernel.org Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman --- fs/nfsd/nfs4state.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -1218,8 +1218,10 @@ static void put_deleg_file(struct nfs4_f if (nf) nfsd_file_put(nf); - if (rnf) + if (rnf) { + nfsd_file_put(rnf); nfs4_file_put_access(fp, NFS4_SHARE_ACCESS_READ); + } } static void nfsd4_finalize_deleg_timestamps(struct nfs4_delegation *dp, struct file *f) @@ -6253,10 +6255,14 @@ nfsd4_add_rdaccess_to_wrdeleg(struct svc fp = stp->st_stid.sc_file; spin_lock(&fp->fi_lock); __nfs4_file_get_access(fp, NFS4_SHARE_ACCESS_READ); - fp = stp->st_stid.sc_file; - fp->fi_fds[O_RDONLY] = nf; - fp->fi_rdeleg_file = nf; + if (!fp->fi_fds[O_RDONLY]) { + fp->fi_fds[O_RDONLY] = nf; + nf = NULL; + } + fp->fi_rdeleg_file = nfsd_file_get(fp->fi_fds[O_RDONLY]); spin_unlock(&fp->fi_lock); + if (nf) + nfsd_file_put(nf); } return true; }