[libvirt] [PATCH] qemu: Double mutex unlock in qemuDomainModifyDeviceFlags

[Jiri Denemark]

On Thu, Jan 17, 2013 at 18:25:28 +0100, Viktor Mihajlovski wrote:
> The driver mutex was unlocked in qemuDomainModifyDeviceFlags before
> entering qemuDomainObjBeginJobWithDriver where it will be unlocked once
> more leaving it in an undefined state. The result was that two
> threads were simultaneously looking up the domain hash table during
> multiple parallel device attach/detach operations.
> Luckily this triggered a virHashIterationError.
> 
> Signed-off-by: Viktor Mihajlovski <mihajlov at linux.vnet.ibm.com>
> ---
>  src/qemu/qemu_driver.c |    1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index 8c39864..c28c223 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -6443,7 +6443,6 @@ qemuDomainModifyDeviceFlags(virDomainPtr dom, const char *xml,
>  
>      qemuDriverLock(driver);
>      vm = virDomainFindByUUID(&driver->domains, dom->uuid);
> -    qemuDriverUnlock(driver);
>      if (!vm) {
>          char uuidstr[VIR_UUID_STRING_BUFLEN];
>          virUUIDFormat(dom->uuid, uuidstr);

ACK. The function relies on driver being locked and unlocks it in
cleanup phase.

Jirka