[PATCH 0/2] Revert parts of g_steal_pointer() rewrite
A few hours ago, I've merged a patch that uses g_steal_pointer() instead of its opened coded alternative. Well, turns out that some areas are more fragile and rely on the open coded version. https://gitlab.com/MichalPrivoznik/libvirt/-/pipelines/275871589 Michal Prívozník (2): virnetsocket: Revert part of g_steal_pointer() rewrite lib: Undo some g_steal_pointer() changes src/libxl/libxl_driver.c | 9 ++++++--- src/lxc/lxc_driver.c | 12 ++++++++---- src/qemu/qemu_driver.c | 36 ++++++++++++++++++++++++------------ src/rpc/virnetsocket.c | 3 ++- 4 files changed, 40 insertions(+), 20 deletions(-) -- 2.26.2
Turns out, the way that glib implements g_steal_pointer() is not compatible with function callbacks. And that's what my recent patch did in virNetSocketEventFree(). Revert that part. Signed-off-by: Michal Privoznik <mprivozn@redhat.com> --- src/rpc/virnetsocket.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/src/rpc/virnetsocket.c b/src/rpc/virnetsocket.c index 5675c0769d..b1f47636d1 100644 --- a/src/rpc/virnetsocket.c +++ b/src/rpc/virnetsocket.c @@ -2156,9 +2156,10 @@ static void virNetSocketEventFree(void *opaque) void *eopaque; virObjectLock(sock); - ff = g_steal_pointer(&sock->ff); + ff = sock->ff; eopaque = g_steal_pointer(&sock->opaque); sock->func = NULL; + sock->ff = NULL; virObjectUnlock(sock); if (ff) -- 2.26.2
Recently, a few commits back I've switched bunch of code to g_steal_pointer() using coccinelle. Problem was that the semantic patch used was slightly off: @@ expression a, b; @@ + b = g_steal_pointer(&a); - b = a; ... when != a - a = NULL; Problem is that, "... when != a" is supposed to jump over those lines, which don't contain expression a. My idea was to replace the following pattern too: ptrX = ptrY; if (something(ptrZ) < 0) goto error; ptrY = NULL; But what I missed is that the following pattern is also matched and replaced: ptrX = ptrY; if (something(ptrX) < 0) goto error; ptrY = NULL; This is not necessarily correct - as demonstrated by our hotplug code. The real problem is ambiguous memory ownership transfer (functions which add device to domain def take ownership only on success), but to not tackle the real issue let's revert those parts. Signed-off-by: Michal Privoznik <mprivozn@redhat.com> --- src/libxl/libxl_driver.c | 9 ++++++--- src/lxc/lxc_driver.c | 12 ++++++++---- src/qemu/qemu_driver.c | 36 ++++++++++++++++++++++++------------ 3 files changed, 38 insertions(+), 19 deletions(-) diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c index 23ef55cf37..5afae01a92 100644 --- a/src/libxl/libxl_driver.c +++ b/src/libxl/libxl_driver.c @@ -3529,7 +3529,7 @@ libxlDomainAttachDeviceConfig(virDomainDefPtr vmdef, virDomainDeviceDefPtr dev) switch (dev->type) { case VIR_DOMAIN_DEVICE_DISK: - disk = g_steal_pointer(&dev->data.disk); + disk = dev->data.disk; if (virDomainDiskIndexByName(vmdef, disk->dst, true) >= 0) { virReportError(VIR_ERR_INVALID_ARG, _("target %s already exists."), disk->dst); @@ -3537,10 +3537,11 @@ libxlDomainAttachDeviceConfig(virDomainDefPtr vmdef, virDomainDeviceDefPtr dev) } virDomainDiskInsert(vmdef, disk); /* vmdef has the pointer. Generic codes for vmdef will do all jobs */ + dev->data.disk = NULL; break; case VIR_DOMAIN_DEVICE_CONTROLLER: - controller = g_steal_pointer(&dev->data.controller); + controller = dev->data.controller; if (controller->idx != -1 && virDomainControllerFind(vmdef, controller->type, controller->idx) >= 0) { @@ -3550,10 +3551,11 @@ libxlDomainAttachDeviceConfig(virDomainDefPtr vmdef, virDomainDeviceDefPtr dev) } virDomainControllerInsert(vmdef, controller); + dev->data.controller = NULL; break; case VIR_DOMAIN_DEVICE_NET: - net = g_steal_pointer(&dev->data.net); + net = dev->data.net; if (virDomainHasNet(vmdef, net)) { virReportError(VIR_ERR_INVALID_ARG, _("network device with mac %s already exists"), @@ -3562,6 +3564,7 @@ libxlDomainAttachDeviceConfig(virDomainDefPtr vmdef, virDomainDeviceDefPtr dev) } if (virDomainNetInsert(vmdef, net)) return -1; + dev->data.net = NULL; break; case VIR_DOMAIN_DEVICE_HOSTDEV: diff --git a/src/lxc/lxc_driver.c b/src/lxc/lxc_driver.c index 3fc15ff2ec..8e0ec82e0b 100644 --- a/src/lxc/lxc_driver.c +++ b/src/lxc/lxc_driver.c @@ -3041,7 +3041,7 @@ lxcDomainAttachDeviceConfig(virDomainDefPtr vmdef, switch (dev->type) { case VIR_DOMAIN_DEVICE_DISK: - disk = g_steal_pointer(&dev->data.disk); + disk = dev->data.disk; if (virDomainDiskIndexByName(vmdef, disk->dst, true) >= 0) { virReportError(VIR_ERR_INVALID_ARG, _("target %s already exists."), disk->dst); @@ -3049,18 +3049,20 @@ lxcDomainAttachDeviceConfig(virDomainDefPtr vmdef, } virDomainDiskInsert(vmdef, disk); /* vmdef has the pointer. Generic codes for vmdef will do all jobs */ + dev->data.disk = NULL; ret = 0; break; case VIR_DOMAIN_DEVICE_NET: - net = g_steal_pointer(&dev->data.net); + net = dev->data.net; if (virDomainNetInsert(vmdef, net) < 0) return -1; + dev->data.net = NULL; ret = 0; break; case VIR_DOMAIN_DEVICE_HOSTDEV: - hostdev = g_steal_pointer(&dev->data.hostdev); + hostdev = dev->data.hostdev; if (virDomainHostdevFind(vmdef, hostdev, NULL) >= 0) { virReportError(VIR_ERR_INVALID_ARG, "%s", _("device is already in the domain configuration")); @@ -3068,6 +3070,7 @@ lxcDomainAttachDeviceConfig(virDomainDefPtr vmdef, } if (virDomainHostdevInsert(vmdef, hostdev) < 0) return -1; + dev->data.hostdev = NULL; ret = 0; break; @@ -3092,7 +3095,7 @@ lxcDomainUpdateDeviceConfig(virDomainDefPtr vmdef, switch (dev->type) { case VIR_DOMAIN_DEVICE_NET: - net = g_steal_pointer(&dev->data.net); + net = dev->data.net; if ((idx = virDomainNetFindIdx(vmdef, net)) < 0) return -1; @@ -3106,6 +3109,7 @@ lxcDomainUpdateDeviceConfig(virDomainDefPtr vmdef, return -1; virDomainNetDefFree(oldDev.data.net); + dev->data.net = NULL; ret = 0; break; diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index b31be76f91..f3f8caab44 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -7238,7 +7238,7 @@ qemuDomainAttachDeviceConfig(virDomainDefPtr vmdef, switch ((virDomainDeviceType)dev->type) { case VIR_DOMAIN_DEVICE_DISK: - disk = g_steal_pointer(&dev->data.disk); + disk = dev->data.disk; if (virDomainDiskIndexByName(vmdef, disk->dst, true) >= 0) { virReportError(VIR_ERR_OPERATION_INVALID, _("target %s already exists"), disk->dst); @@ -7250,22 +7250,25 @@ qemuDomainAttachDeviceConfig(virDomainDefPtr vmdef, return -1; virDomainDiskInsert(vmdef, disk); /* vmdef has the pointer. Generic codes for vmdef will do all jobs */ + dev->data.disk = NULL; break; case VIR_DOMAIN_DEVICE_NET: - net = g_steal_pointer(&dev->data.net); + net = dev->data.net; if (virDomainNetInsert(vmdef, net)) return -1; + dev->data.net = NULL; break; case VIR_DOMAIN_DEVICE_SOUND: - sound = g_steal_pointer(&dev->data.sound); + sound = dev->data.sound; if (VIR_APPEND_ELEMENT(vmdef->sounds, vmdef->nsounds, sound) < 0) return -1; + dev->data.sound = NULL; break; case VIR_DOMAIN_DEVICE_HOSTDEV: - hostdev = g_steal_pointer(&dev->data.hostdev); + hostdev = dev->data.hostdev; if (virDomainHostdevFind(vmdef, hostdev, NULL) >= 0) { virReportError(VIR_ERR_OPERATION_INVALID, "%s", _("device is already in the domain configuration")); @@ -7273,10 +7276,11 @@ qemuDomainAttachDeviceConfig(virDomainDefPtr vmdef, } if (virDomainHostdevInsert(vmdef, hostdev)) return -1; + dev->data.hostdev = NULL; break; case VIR_DOMAIN_DEVICE_LEASE: - lease = g_steal_pointer(&dev->data.lease); + lease = dev->data.lease; if (virDomainLeaseIndex(vmdef, lease) >= 0) { virReportError(VIR_ERR_OPERATION_INVALID, _("Lease %s in lockspace %s already exists"), @@ -7286,10 +7290,11 @@ qemuDomainAttachDeviceConfig(virDomainDefPtr vmdef, virDomainLeaseInsert(vmdef, lease); /* vmdef has the pointer. Generic codes for vmdef will do all jobs */ + dev->data.lease = NULL; break; case VIR_DOMAIN_DEVICE_CONTROLLER: - controller = g_steal_pointer(&dev->data.controller); + controller = dev->data.controller; if (controller->idx != -1 && virDomainControllerFind(vmdef, controller->type, controller->idx) >= 0) { @@ -7300,6 +7305,7 @@ qemuDomainAttachDeviceConfig(virDomainDefPtr vmdef, } virDomainControllerInsert(vmdef, controller); + dev->data.controller = NULL; break; @@ -7310,7 +7316,7 @@ qemuDomainAttachDeviceConfig(virDomainDefPtr vmdef, break; case VIR_DOMAIN_DEVICE_FS: - fs = g_steal_pointer(&dev->data.fs); + fs = dev->data.fs; if (virDomainFSIndexByName(vmdef, fs->dst) >= 0) { virReportError(VIR_ERR_OPERATION_INVALID, "%s", _("Target already exists")); @@ -7319,6 +7325,7 @@ qemuDomainAttachDeviceConfig(virDomainDefPtr vmdef, if (virDomainFSInsert(vmdef, fs) < 0) return -1; + dev->data.fs = NULL; break; case VIR_DOMAIN_DEVICE_RNG: @@ -7350,14 +7357,15 @@ qemuDomainAttachDeviceConfig(virDomainDefPtr vmdef, break; case VIR_DOMAIN_DEVICE_REDIRDEV: - redirdev = g_steal_pointer(&dev->data.redirdev); + redirdev = dev->data.redirdev; if (VIR_APPEND_ELEMENT(vmdef->redirdevs, vmdef->nredirdevs, redirdev) < 0) return -1; + dev->data.redirdev = NULL; break; case VIR_DOMAIN_DEVICE_SHMEM: - shmem = g_steal_pointer(&dev->data.shmem); + shmem = dev->data.shmem; if (virDomainShmemDefFind(vmdef, shmem) >= 0) { virReportError(VIR_ERR_OPERATION_INVALID, "%s", _("device is already in the domain configuration")); @@ -7365,6 +7373,7 @@ qemuDomainAttachDeviceConfig(virDomainDefPtr vmdef, } if (virDomainShmemDefInsert(vmdef, shmem) < 0) return -1; + dev->data.shmem = NULL; break; case VIR_DOMAIN_DEVICE_WATCHDOG: @@ -7636,7 +7645,7 @@ qemuDomainUpdateDeviceConfig(virDomainDefPtr vmdef, switch ((virDomainDeviceType)dev->type) { case VIR_DOMAIN_DEVICE_DISK: - newDisk = g_steal_pointer(&dev->data.disk); + newDisk = dev->data.disk; if ((pos = virDomainDiskIndexByName(vmdef, newDisk->dst, false)) < 0) { virReportError(VIR_ERR_INVALID_ARG, _("target %s doesn't exist."), newDisk->dst); @@ -7651,10 +7660,11 @@ qemuDomainUpdateDeviceConfig(virDomainDefPtr vmdef, virDomainDiskDefFree(vmdef->disks[pos]); vmdef->disks[pos] = newDisk; + dev->data.disk = NULL; break; case VIR_DOMAIN_DEVICE_GRAPHICS: - newGraphics = g_steal_pointer(&dev->data.graphics); + newGraphics = dev->data.graphics; pos = qemuDomainFindGraphicsIndex(vmdef, newGraphics); if (pos < 0) { virReportError(VIR_ERR_INVALID_ARG, @@ -7671,10 +7681,11 @@ qemuDomainUpdateDeviceConfig(virDomainDefPtr vmdef, virDomainGraphicsDefFree(vmdef->graphics[pos]); vmdef->graphics[pos] = newGraphics; + dev->data.graphics = NULL; break; case VIR_DOMAIN_DEVICE_NET: - net = g_steal_pointer(&dev->data.net); + net = dev->data.net; if ((pos = virDomainNetFindIdx(vmdef, net)) < 0) return -1; @@ -7688,6 +7699,7 @@ qemuDomainUpdateDeviceConfig(virDomainDefPtr vmdef, return -1; virDomainNetDefFree(oldDev.data.net); + dev->data.net = NULL; break; case VIR_DOMAIN_DEVICE_FS: -- 2.26.2
On Wed, Mar 24, 2021 at 19:01:47 +0100, Michal Privoznik wrote:
A few hours ago, I've merged a patch that uses g_steal_pointer() instead of its opened coded alternative. Well, turns out that some areas are more fragile and rely on the open coded version.
https://gitlab.com/MichalPrivoznik/libvirt/-/pipelines/275871589
Michal Prívozník (2): virnetsocket: Revert part of g_steal_pointer() rewrite lib: Undo some g_steal_pointer() changes
Reviewed-by: Peter Krempa <pkrempa@redhat.com> but note that I didn't comprehensively check the patch that broke things that you've fixed all instances.
participants (2)
-
Michal Privoznik -
Peter Krempa