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Re: [Qemu-devel] [PATCH v2 3/4] qga: win32: fix crashes when PCI info ca
From: |
Michael Roth |
Subject: |
Re: [Qemu-devel] [PATCH v2 3/4] qga: win32: fix crashes when PCI info cannot be retrived |
Date: |
Wed, 05 Sep 2018 18:21:07 -0500 |
User-agent: |
alot/0.7 |
Quoting Tomáš Golembiovský (2018-08-07 05:51:37)
> The guest-get-fsinfo command collects also information about PCI
> controller where the disk is attached. When this fails for some reasons
> it tries to return just the partial information. However in certain
> cases the pointer to the structure was not initialized and was set to
> NULL. This breaks the serializer and lead to crasehs of the guest agent.
>
> Signed-off-by: Tomáš Golembiovský <address@hidden>
> ---
> qga/commands-win32.c | 27 ++++++++++++++++++++++-----
> 1 file changed, 22 insertions(+), 5 deletions(-)
>
> diff --git a/qga/commands-win32.c b/qga/commands-win32.c
> index 36d76c22c0..995f62c2e4 100644
> --- a/qga/commands-win32.c
> +++ b/qga/commands-win32.c
> @@ -642,15 +642,32 @@ static GuestDiskAddressList *build_guest_disk_info(char
> *guid, Error **errp)
> g_debug("getting pci-controller info");
> if (DeviceIoControl(vol_h, IOCTL_SCSI_GET_ADDRESS, NULL, 0, scsi_ad,
> sizeof(SCSI_ADDRESS), &len, NULL)) {
> + Error *local_err = NULL;
> disk->unit = addr.Lun;
> disk->target = addr.TargetId;
> disk->bus = addr.PathId;
> - disk->pci_controller = get_pci_info(name, errp);
> + g_debug("unit=%lld target=%lld bus=%lld",
> + disk->unit, disk->target, disk->bus);
> + disk->pci_controller = get_pci_info(name, &local_err);
> +
> + if (local_err) {
> + slog("failed to get PCI controller info: %s",
> + error_get_pretty(local_err));
slog() is more for logging/auditing events that a guest administrator might
be interested in knowing about, like when qga is accessing files, freezing
filesystems, etc. General qga-side error reporting and debug logging should
go through the normal g_debug/g_warning/etc interfaces to be captured in
qga's log file.
We should also moved patch 1 after this so we don't expose a breakage
prior to the fix.
How often are you seeing failures with the pci info? And does the
information for the non-failures look valid to you? I tried to fix the
CONFIG_QGA_NTDDSCSI naming screw-up a while back and some values like
PCI func/bus/etc looked bogus, SPDRP_BUSNUMBER/SPDRP_ADDRESS/SPDRP_BUSNUMBER
didn't seem to be returning what the current code thinks they are. If that's
still the case it would be good to fix that before we final re-enable this
code.
> + error_free(local_err);
> + } else if (disk->pci_controller != NULL) {
> + g_debug("pci: domain=%lld bus=%lld slot=%lld function=%lld",
> + disk->pci_controller->domain,
> + disk->pci_controller->bus,
> + disk->pci_controller->slot,
> + disk->pci_controller->function);
> + }
> }
> - /* We do not set error in this case, because we still have enough
> - * information about volume. */
> - } else {
> - disk->pci_controller = NULL;
> + }
> + /* We do not set error in case pci_controller is NULL, because we still
> + * have enough information about volume. */
> + if (disk->pci_controller == NULL) {
> + g_debug("no PCI controller info");
> + disk->pci_controller = g_malloc0(sizeof(GuestPCIAddress));
> }
>
> list = g_malloc0(sizeof(*list));
> --
> 2.18.0
>
- Re: [Qemu-devel] [PATCH v2 3/4] qga: win32: fix crashes when PCI info cannot be retrived,
Michael Roth <=