From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756190AbcJSBYC (ORCPT ); Tue, 18 Oct 2016 21:24:02 -0400 Received: from LGEAMRELO13.lge.com ([156.147.23.53]:43003 "EHLO lgeamrelo13.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752089AbcJSBYB (ORCPT ); Tue, 18 Oct 2016 21:24:01 -0400 X-Original-SENDERIP: 156.147.1.127 X-Original-MAILFROM: namhyung@kernel.org X-Original-SENDERIP: 10.177.227.17 X-Original-MAILFROM: namhyung@kernel.org From: Namhyung Kim To: Kees Cook Cc: Anton Vorontsov , Colin Cross , Tony Luck , LKML , Stefan Hajnoczi Subject: [RFC/PATCH 1/2] pstore: Protect unlink with read_mutex Date: Wed, 19 Oct 2016 10:23:40 +0900 Message-Id: <20161019012341.8032-1-namhyung@kernel.org> X-Mailer: git-send-email 2.9.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When update_ms is set, pstore_get_records() will be called when there's a new entry. But unlink can be called at the same time and might contend with the open-read-close loop. Depending on the implementation of platform driver, it may be safe or not. But I think it'd be better to protect those race in the first place. Cc: Stefan Hajnoczi Signed-off-by: Namhyung Kim --- fs/pstore/inode.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c index 1781dc50762e..75728dfae0a6 100644 --- a/fs/pstore/inode.c +++ b/fs/pstore/inode.c @@ -197,11 +197,14 @@ static int pstore_unlink(struct inode *dir, struct dentry *dentry) if (err) return err; - if (p->psi->erase) + if (p->psi->erase) { + mutex_lock(&p->psi->read_mutex); p->psi->erase(p->type, p->id, p->count, d_inode(dentry)->i_ctime, p->psi); - else + mutex_unlock(&p->psi->read_mutex); + } else { return -EPERM; + } return simple_unlink(dir, dentry); } -- 2.9.3