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 714D112B7A for ; Mon, 23 Oct 2023 11:12:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="bniVkuld" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E31B7C433C8; Mon, 23 Oct 2023 11:12:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1698059525; bh=t0b0x/PH7fgaTaHpq++5o5hDNbZDbdFdTeXJR+mwI8U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bniVkuld9SjCa0P/ommeoTX+8yX6sWnwZOVbtgHW8ctAOK9pT/LXZHKAl0ZLGGihW 7i9f5wnUsF9GXKga78aFJDDuiNqddhsvmi35LzW10uowNktdBhJsp/Kd1Fj6HByKRE oSBdebsrz+B5svciRWvVz3oQB3gKy7UsmULWdV+g= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Trond Myklebust , Anna Schumaker Subject: [PATCH 6.5 179/241] pNFS: Fix a hang in nfs4_evict_inode() Date: Mon, 23 Oct 2023 12:56:05 +0200 Message-ID: <20231023104838.246889066@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231023104833.832874523@linuxfoundation.org> References: <20231023104833.832874523@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Trond Myklebust commit f63955721a8020e979b99cc417dcb6da3106aa24 upstream. We are not allowed to call pnfs_mark_matching_lsegs_return() without also holding a reference to the layout header, since doing so could lead to the reference count going to zero when we call pnfs_layout_remove_lseg(). This again can lead to a hang when we get to nfs4_evict_inode() and are unable to clear the layout pointer. pnfs_layout_return_unused_byserver() is guilty of this behaviour, and has been seen to trigger the refcount warning prior to a hang. Fixes: b6d49ecd1081 ("NFSv4: Fix a pNFS layout related use-after-free race when freeing the inode") Cc: stable@vger.kernel.org Signed-off-by: Trond Myklebust Signed-off-by: Anna Schumaker Signed-off-by: Greg Kroah-Hartman --- fs/nfs/pnfs.c | 33 +++++++++++++++++++++++---------- 1 file changed, 23 insertions(+), 10 deletions(-) --- a/fs/nfs/pnfs.c +++ b/fs/nfs/pnfs.c @@ -2634,31 +2634,44 @@ pnfs_should_return_unused_layout(struct return mode == 0; } -static int -pnfs_layout_return_unused_byserver(struct nfs_server *server, void *data) +static int pnfs_layout_return_unused_byserver(struct nfs_server *server, + void *data) { const struct pnfs_layout_range *range = data; + const struct cred *cred; struct pnfs_layout_hdr *lo; struct inode *inode; + nfs4_stateid stateid; + enum pnfs_iomode iomode; + restart: rcu_read_lock(); list_for_each_entry_rcu(lo, &server->layouts, plh_layouts) { - if (!pnfs_layout_can_be_returned(lo) || + inode = lo->plh_inode; + if (!inode || !pnfs_layout_can_be_returned(lo) || test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags)) continue; - inode = lo->plh_inode; spin_lock(&inode->i_lock); - if (!pnfs_should_return_unused_layout(lo, range)) { + if (!lo->plh_inode || + !pnfs_should_return_unused_layout(lo, range)) { spin_unlock(&inode->i_lock); continue; } + pnfs_get_layout_hdr(lo); + pnfs_set_plh_return_info(lo, range->iomode, 0); + if (pnfs_mark_matching_lsegs_return(lo, &lo->plh_return_segs, + range, 0) != 0 || + !pnfs_prepare_layoutreturn(lo, &stateid, &cred, &iomode)) { + spin_unlock(&inode->i_lock); + rcu_read_unlock(); + pnfs_put_layout_hdr(lo); + cond_resched(); + goto restart; + } spin_unlock(&inode->i_lock); - inode = pnfs_grab_inode_layout_hdr(lo); - if (!inode) - continue; rcu_read_unlock(); - pnfs_mark_layout_for_return(inode, range); - iput(inode); + pnfs_send_layoutreturn(lo, &stateid, &cred, iomode, false); + pnfs_put_layout_hdr(lo); cond_resched(); goto restart; }