From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758532AbXGIQ0p (ORCPT ); Mon, 9 Jul 2007 12:26:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757522AbXGIQXb (ORCPT ); Mon, 9 Jul 2007 12:23:31 -0400 Received: from mx1.redhat.com ([66.187.233.31]:41913 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757438AbXGIQX3 (ORCPT ); Mon, 9 Jul 2007 12:23:29 -0400 From: swhiteho@redhat.com To: linux-kernel@vger.kernel.org Cc: cluster-devel@redhat.com, Josef Bacik , Steven Whitehouse Subject: [PATCH] [DLM] keep dlm from panicing when traversing rsb list in debugfs Date: Mon, 9 Jul 2007 17:02:16 +0100 Message-Id: <11839970101065-git-send-email-swhiteho@redhat.com> X-Mailer: git-send-email 1.5.1.2 In-Reply-To: <1183997008395-git-send-email-swhiteho@redhat.com> References: <11839969822277-git-send-email-swhiteho@redhat.com> <1183996989263-git-send-email-swhiteho@redhat.com> <11839969911617-git-send-email-swhiteho@redhat.com> <1183996996300-git-send-email-swhiteho@redhat.com> <11839969982134-git-send-email-swhiteho@redhat.com> <11839970003764-git-send-email-swhiteho@redhat.com> <11839970032102-git-send-email-swhiteho@redhat.com> <11839970052865-git-send-email-swhiteho@redhat.com> <11839970061096-git-send-email-swhiteho@redhat.com> <1183997008395-git-send-email-swhiteho@redhat.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org From: Josef Bacik This problem was originally reported against GFS6.1, but the same issue exists in upstream DLM. This patch keeps the rsb iterator assigning under the rsbtbl list lock. Each time we process an rsb we grab a reference to it to make sure it is not freed out from underneath us, and then put it when we get the next rsb in the list or move onto another list. Signed-off-by: Josef Bacik Signed-off-by: Steven Whitehouse diff --git a/fs/dlm/debug_fs.c b/fs/dlm/debug_fs.c index 61ba670..9e27a16 100644 --- a/fs/dlm/debug_fs.c +++ b/fs/dlm/debug_fs.c @@ -17,6 +17,7 @@ #include #include "dlm_internal.h" +#include "lock.h" #define DLM_DEBUG_BUF_LEN 4096 static char debug_buf[DLM_DEBUG_BUF_LEN]; @@ -166,6 +167,9 @@ static int rsb_iter_next(struct rsb_iter *ri) read_lock(&ls->ls_rsbtbl[i].lock); if (!list_empty(&ls->ls_rsbtbl[i].list)) { ri->next = ls->ls_rsbtbl[i].list.next; + ri->rsb = list_entry(ri->next, struct dlm_rsb, + res_hashchain); + dlm_hold_rsb(ri->rsb); read_unlock(&ls->ls_rsbtbl[i].lock); break; } @@ -176,6 +180,7 @@ static int rsb_iter_next(struct rsb_iter *ri) if (ri->entry >= ls->ls_rsbtbl_size) return 1; } else { + struct dlm_rsb *old = ri->rsb; i = ri->entry; read_lock(&ls->ls_rsbtbl[i].lock); ri->next = ri->next->next; @@ -184,11 +189,13 @@ static int rsb_iter_next(struct rsb_iter *ri) ri->next = NULL; ri->entry++; read_unlock(&ls->ls_rsbtbl[i].lock); + dlm_put_rsb(old); goto top; } + ri->rsb = list_entry(ri->next, struct dlm_rsb, res_hashchain); read_unlock(&ls->ls_rsbtbl[i].lock); + dlm_put_rsb(old); } - ri->rsb = list_entry(ri->next, struct dlm_rsb, res_hashchain); return 0; } -- 1.5.1.2