From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57702) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dI4mf-0007CK-1E for qemu-devel@nongnu.org; Mon, 05 Jun 2017 23:03:54 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dI4me-0008Fv-63 for qemu-devel@nongnu.org; Mon, 05 Jun 2017 23:03:53 -0400 Date: Tue, 6 Jun 2017 11:03:34 +0800 From: Peter Xu Message-ID: <20170606030334.GA23580@pxdev.xzpeter.org> References: <20170605104851.61818-1-haoqf@linux.vnet.ibm.com> <20170605104851.61818-2-haoqf@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20170605104851.61818-2-haoqf@linux.vnet.ibm.com> Subject: Re: [Qemu-devel] [PATCH v1 1/1] qemu/migration: fix the double free problem on from_src_file List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: QingFeng Hao Cc: qemu-devel@nongnu.org, qemu-block@nongnu.org, borntraeger@de.ibm.com, cornelia.huck@de.ibm.com, liujbjl@linux.vnet.ibm.com, kwolf@redhat.com, famz@redhat.com On Mon, Jun 05, 2017 at 12:48:51PM +0200, QingFeng Hao wrote: > In load_vmstate, mis->from_src_file is freed twice, the first free is by > qemu_fclose, the second is by migration_incoming_state_destroy and > it causes Illegal instruction exception. The fix is just to remove the > first free. > > This problem is found by qemu-iotests case 068 since commit > "660819b migration: shut src return path unconditionally". The error is: > 068 1s ... - output mismatch (see 068.out.bad) > --- tests/qemu-iotests/068.out 2017-05-06 01:00:26.417270437 +0200 > +++ 068.out.bad 2017-06-03 13:59:55.360274640 +0200 > @@ -6,6 +6,8 @@ > QEMU X.Y.Z monitor - type 'help' for more information > (qemu) savevm 0 > (qemu) quit > +./common.config: line 107: 242472 Illegal instruction (core dumped) ( if [ -n "${QEMU_NEED_PID}" ]; then > + echo $BASHPID > "${QEMU_TEST_DIR}/qemu-${_QEMU_HANDLE}.pid"; > +fi; exec "$QEMU_PROG" $QEMU_OPTIONS "$@" ) > QEMU X.Y.Z monitor - type 'help' for more information > -(qemu) quit > -*** done > +(qemu) *** done > > Signed-off-by: QingFeng Hao > --- > migration/savevm.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/migration/savevm.c b/migration/savevm.c > index 9c320f59d0..853e14e34e 100644 > --- a/migration/savevm.c > +++ b/migration/savevm.c > @@ -2290,7 +2290,6 @@ int load_snapshot(const char *name, Error **errp) > > aio_context_acquire(aio_context); > ret = qemu_loadvm_state(f); > - qemu_fclose(f); > aio_context_release(aio_context); > > migration_incoming_state_destroy(); Thanks QingFeng for the fix! Reviewed-by: Peter Xu Though here instead of removing the fclose(), not sure whether this is nicer: diff --git a/migration/savevm.c b/migration/savevm.c index 9c320f5..1feb519 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -2233,7 +2233,6 @@ int load_snapshot(const char *name, Error **errp) QEMUFile *f; int ret; AioContext *aio_context; - MigrationIncomingState *mis = migration_incoming_get_current(); if (!bdrv_all_can_snapshot(&bs)) { error_setg(errp, @@ -2286,7 +2285,6 @@ int load_snapshot(const char *name, Error **errp) } qemu_system_reset(SHUTDOWN_CAUSE_NONE); - mis->from_src_file = f; aio_context_acquire(aio_context); ret = qemu_loadvm_state(f); Since I see we setup from_src_file but we don't really use it. If we remove that line, we can also remove the migration_incoming_get_current() call altogether. Either way work for me. So my r-b stands always. :-) -- Peter Xu