Hi Thomas,
thanks for the response.
> On Wed, 19 Dec 2012, Koehrer Mathias (ETAS/ESS2) wrote:
> > > >
> > > > I have detected the following issue:
> > > > I use an x86 PC using kernel 3.2.34-rt51 and I want to run VirtualBox 4.2.4
> using
> > > this PC as host.
> > >
> > > > However, the PC freezes completely when loading the vbox driver "vboxdrv".
> > > > Using the very same kernel without the RT_PREEMPT patch shows no issues.
> > > >
> > > > Using an older version of VirtualBox (V4.1.22) works fine as well.
> > > >
> > > > I know that this might be slightly off-topic. However there might be some
> > > RT_PREEMPT users that have detected the same issue and know a solution for
> this.
> > >
> > > (...)
> > > Try enabling lock debugging. Likely there is an incompatibility in the
> > > vbox driver or even a bug, and that may reveal more details.
> >
> > In addition, I did a long debug session (using a parallel port LED adapter any
> many PC resets...) to identify the issue.
> > Lock debugging did not work as really everything was frozen or the PC.
> > However, I finally identified the critical lines of code.
> > The relevant source file is the attached file "spinlock-r0drv-linux.c" of the
> VirtualBox OSE V4.2.4.
> > The freeze happens in line 158 (spin_unlock_irqrestore()).
> >
> > ----------- BEGIN CODE FRAGMENT --------------------
> > RTDECL(void) RTSpinlockRelease(RTSPINLOCK Spinlock)
> > {
> > PRTSPINLOCKINTERNAL pThis = (PRTSPINLOCKINTERNAL)Spinlock;
> > RT_ASSERT_PREEMPT_CPUID_SPIN_RELEASE_VARS();
> > AssertMsg(pThis && pThis->u32Magic == RTSPINLOCK_MAGIC,
> > ("pThis=%p u32Magic=%08x\n", pThis, pThis ? (int)pThis->u32Magic :
> 0));
> > RT_ASSERT_PREEMPT_CPUID_SPIN_RELEASE(pThis);
> >
> > if (pThis->fFlags & RTSPINLOCK_FLAGS_INTERRUPT_SAFE)
> > {
> > unsigned long fIntSaved = pThis->fIntSaved;
> > pThis->fIntSaved = 0;
> > spin_unlock_irqrestore(&pThis->Spinlock, fIntSaved); // <--- Here is the
> freeze!
> > }
> > else
> > spin_unlock(&pThis->Spinlock);
> >
> > RT_ASSERT_PREEMPT_CPUID();
> > }
> > RT_EXPORT_SYMBOL(RTSpinlockRelease);
> > ----------- END CODE FRAGMENT --------------------
>
> Was it really necessary to expose us to the camel case inflicted
> horror of the VirtualBox spinlock abstraction layer just a few days
> before Christmas?
Sorry for that!
> You said:
> > Lock debugging did not work as really everything was frozen or the PC.
>
> That's an indicator that something is really wrong. Can you just run
> the same crap on a non-rt kernel with CONFIG_PROVE_LOCKING enabled ?
I did. It shows actually an error.
Here is the relevant dmesg output:
--------------- BEGIN dmesg output -----------------
vboxdrv: Found 4 processor cores.
vboxdrv: fAsync=0 offMin=0x50c offMax=0x5940
=================================
[ INFO: inconsistent lock state ]
3.2.34-2 #1
---------------------------------
inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage.
swapper/1/0 [HC1[1]:SC0[0]:HE0:SE1] takes:
(&(&pThis->Spinlock)->rlock){?.+...}, at: [<f883c7a9>] VBoxHost_RTSpinlockAcquire+0x15/0x24 [vboxdrv]
{HARDIRQ-ON-W} state was registered at:
[<c104b99a>] __lock_acquire+0x509/0x1337
[<c104cb3a>] lock_acquire+0x42/0x59
[<c13204d5>] _raw_spin_lock+0x25/0x34
[<f883c7b3>] VBoxHost_RTSpinlockAcquire+0x1f/0x24 [vboxdrv]
[<f883986f>] VBoxHost_RTMpNotificationRegister+0x36/0x11a [vboxdrv]
[<f88324f8>] supdrvInitDevExt+0x4f4/0x65c [vboxdrv]
[<f8868053>] VBoxDrvLinuxInit+0x53/0xcd [vboxdrv]
[<c100106b>] do_one_initcall+0x6b/0x10c
[<c1054299>] sys_init_module+0x122f/0x13fa
[<c1321990>] sysenter_do_call+0x12/0x36
irq event stamp: 278096
hardirqs last enabled at (278093): [<c1007c3a>] mwait_idle+0x57/0x7c
hardirqs last disabled at (278094): [<c1320f34>] call_function_interrupt+0x28/0x34
softirqs last enabled at (278096): [<c102e3db>] _local_bh_enable+0xd/0xf
softirqs last disabled at (278095): [<c102e7a8>] irq_enter+0x29/0x4e
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&(&pThis->Spinlock)->rlock);
<Interrupt>
lock(&(&pThis->Spinlock)->rlock);
*** DEADLOCK ***
no locks held by swapper/1/0.
stack backtrace:
Pid: 0, comm: swapper/1 Tainted: G O 3.2.34-2 #1
Call Trace:
[<c131c0bb>] print_usage_bug.part.27+0x1f0/0x1fa
[<c104b313>] mark_lock+0x334/0x4b2
[<c104a95b>] ? check_usage_backwards+0xce/0xce
[<c104b92d>] __lock_acquire+0x49c/0x1337
[<c104cb3a>] lock_acquire+0x42/0x59
[<f883c7a9>] ? VBoxHost_RTSpinlockAcquire+0x15/0x24 [vboxdrv]
[<c1320583>] _raw_spin_lock_irqsave+0x2e/0x3e
[<f883c7a9>] ? VBoxHost_RTSpinlockAcquire+0x15/0x24 [vboxdrv]
[<f883c7a9>] VBoxHost_RTSpinlockAcquire+0x15/0x24 [vboxdrv]
[<f8831d69>] ? supdrvGipMpEventOnline+0x14d/0x14d [vboxdrv]
[<f8831c77>] supdrvGipMpEventOnline+0x5b/0x14d [vboxdrv]
[<f8831d69>] ? supdrvGipMpEventOnline+0x14d/0x14d [vboxdrv]
[<f8831d77>] supdrvGipInitOnCpu+0xe/0x10 [vboxdrv]
[<f883b688>] rtmpLinuxWrapper+0x22/0x2d [vboxdrv]
[<f883b666>] ? VBoxHost_RTMpCpuId+0xa/0xa [vboxdrv]
[<c1051253>] generic_smp_call_function_interrupt+0x6b/0x112
[<c1014595>] smp_call_function_interrupt+0x20/0x2e
[<c1320f3b>] call_function_interrupt+0x2f/0x34
[<c104007b>] ? __run_hrtimer.isra.28+0x33/0x9e
[<c1007c42>] ? mwait_idle+0x5f/0x7c
[<c10014c2>] cpu_idle+0x4d/0x76
[<c14ff2e8>] start_secondary+0x1ab/0x1b2
vboxdrv: TSC mode is 'synchronous', kernel timer mode is 'normal'.
vboxdrv: Successfully loaded version 4.2.4 (interface 0x001a0004).
vboxpci: pci-stub module not available, cannot detach PCI devices
vboxpci: IOMMU not found (not compiled)
--------------- END dmesg output -----------------
I attached the kernel configuration used for this test.
Thanks for the support.
Regards and merry Christmas.
Mathias
Attachment:
config.gz
Description: config.gz
