From mboxrd@z Thu Jan 1 00:00:00 1970 From: Juan Quintela Subject: Re: [PATCH 05/18] vl.c: add deleted flag for deleting the handler. Date: Wed, 23 Feb 2011 23:04:44 +0100 Message-ID: References: <1298468927-19193-1-git-send-email-tamura.yoshiaki@lab.ntt.co.jp> <1298468927-19193-6-git-send-email-tamura.yoshiaki@lab.ntt.co.jp> Reply-To: quintela@redhat.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm@vger.kernel.org, qemu-devel@nongnu.org, kwolf@redhat.com, aliguori@us.ibm.com, mtosatti@redhat.com, ananth@in.ibm.com, mst@redhat.com, dlaor@redhat.com, vatsa@linux.vnet.ibm.com, blauwirbel@gmail.com, ohmura.kei@lab.ntt.co.jp, avi@redhat.com, pbonzini@redhat.com, psuriset@linux.vnet.ibm.com, stefanha@linux.vnet.ibm.com To: Yoshiaki Tamura Return-path: Received: from mx1.redhat.com ([209.132.183.28]:1025 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753546Ab1BWWJZ (ORCPT ); Wed, 23 Feb 2011 17:09:25 -0500 In-Reply-To: <1298468927-19193-6-git-send-email-tamura.yoshiaki@lab.ntt.co.jp> (Yoshiaki Tamura's message of "Wed, 23 Feb 2011 22:48:34 +0900") Sender: kvm-owner@vger.kernel.org List-ID: Yoshiaki Tamura wrote: > Make deleting handlers robust against deletion of any elements in a > handler by using a deleted flag like in file descriptors. > > Signed-off-by: Yoshiaki Tamura > --- > vl.c | 13 +++++++++---- > 1 files changed, 9 insertions(+), 4 deletions(-) > > diff --git a/vl.c b/vl.c > index b436952..4e263c3 100644 > --- a/vl.c > +++ b/vl.c > @@ -1158,6 +1158,7 @@ static void nographic_update(void *opaque) > struct vm_change_state_entry { > VMChangeStateHandler *cb; > void *opaque; > + int deleted; > QLIST_ENTRY (vm_change_state_entry) entries; > }; > > @@ -1178,8 +1179,7 @@ VMChangeStateEntry *qemu_add_vm_change_state_handler(VMChangeStateHandler *cb, > > void qemu_del_vm_change_state_handler(VMChangeStateEntry *e) > { > - QLIST_REMOVE (e, entries); > - qemu_free (e); > + e->deleted = 1; > } > > void vm_state_notify(int running, int reason) > @@ -1188,8 +1188,13 @@ void vm_state_notify(int running, int reason) > > trace_vm_state_notify(running, reason); > > - for (e = vm_change_state_head.lh_first; e; e = e->entries.le_next) { > - e->cb(e->opaque, running, reason); this needs to become: > + QLIST_FOREACH(e, &vm_change_state_head, entries) { > + if (e->deleted) { > + QLIST_REMOVE(e, entries); > + qemu_free(e); > + } else { > + e->cb(e->opaque, running, reason); > + } VMChangeState_entry *next; QLIST_FOREACH_SAFE(e, &vm_change_state_head, entries, next) { ..... Otherwise you are accessing "e" after qemu_free and being put out of the list. Later, Juan. From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=38262 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PsNOo-0002SP-8H for qemu-devel@nongnu.org; Wed, 23 Feb 2011 17:41:35 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PsMsO-0000Bz-A9 for qemu-devel@nongnu.org; Wed, 23 Feb 2011 17:08:05 -0500 Received: from mx1.redhat.com ([209.132.183.28]:59259) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PsMsN-0000Bp-SG for qemu-devel@nongnu.org; Wed, 23 Feb 2011 17:08:04 -0500 From: Juan Quintela In-Reply-To: <1298468927-19193-6-git-send-email-tamura.yoshiaki@lab.ntt.co.jp> (Yoshiaki Tamura's message of "Wed, 23 Feb 2011 22:48:34 +0900") References: <1298468927-19193-1-git-send-email-tamura.yoshiaki@lab.ntt.co.jp> <1298468927-19193-6-git-send-email-tamura.yoshiaki@lab.ntt.co.jp> Date: Wed, 23 Feb 2011 23:04:44 +0100 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Subject: [Qemu-devel] Re: [PATCH 05/18] vl.c: add deleted flag for deleting the handler. Reply-To: quintela@redhat.com List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Yoshiaki Tamura Cc: kwolf@redhat.com, aliguori@us.ibm.com, dlaor@redhat.com, ananth@in.ibm.com, kvm@vger.kernel.org, mst@redhat.com, mtosatti@redhat.com, qemu-devel@nongnu.org, vatsa@linux.vnet.ibm.com, blauwirbel@gmail.com, ohmura.kei@lab.ntt.co.jp, avi@redhat.com, pbonzini@redhat.com, psuriset@linux.vnet.ibm.com, stefanha@linux.vnet.ibm.com Yoshiaki Tamura wrote: > Make deleting handlers robust against deletion of any elements in a > handler by using a deleted flag like in file descriptors. > > Signed-off-by: Yoshiaki Tamura > --- > vl.c | 13 +++++++++---- > 1 files changed, 9 insertions(+), 4 deletions(-) > > diff --git a/vl.c b/vl.c > index b436952..4e263c3 100644 > --- a/vl.c > +++ b/vl.c > @@ -1158,6 +1158,7 @@ static void nographic_update(void *opaque) > struct vm_change_state_entry { > VMChangeStateHandler *cb; > void *opaque; > + int deleted; > QLIST_ENTRY (vm_change_state_entry) entries; > }; > > @@ -1178,8 +1179,7 @@ VMChangeStateEntry *qemu_add_vm_change_state_handler(VMChangeStateHandler *cb, > > void qemu_del_vm_change_state_handler(VMChangeStateEntry *e) > { > - QLIST_REMOVE (e, entries); > - qemu_free (e); > + e->deleted = 1; > } > > void vm_state_notify(int running, int reason) > @@ -1188,8 +1188,13 @@ void vm_state_notify(int running, int reason) > > trace_vm_state_notify(running, reason); > > - for (e = vm_change_state_head.lh_first; e; e = e->entries.le_next) { > - e->cb(e->opaque, running, reason); this needs to become: > + QLIST_FOREACH(e, &vm_change_state_head, entries) { > + if (e->deleted) { > + QLIST_REMOVE(e, entries); > + qemu_free(e); > + } else { > + e->cb(e->opaque, running, reason); > + } VMChangeState_entry *next; QLIST_FOREACH_SAFE(e, &vm_change_state_head, entries, next) { ..... Otherwise you are accessing "e" after qemu_free and being put out of the list. Later, Juan.