Re: [Qemu-devel] "BUG: soft lockup detected on CPU#0!"

["Atif Hashmi" <atifhashmi@gmail.com>]

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Hi Shashi,

I think it is sufficient to add your intercept code in ops_mem.h. I am not
sure about the writes from the I/O though.

Regards,
Atif

On 5/17/07, Shashidhar Mysore <shashimc@gmail.com> wrote:
>
> Hi Atif,
>
> Thanks for the quick reply. Yes, you are right, I want to consider all
> updates to memory. Can you tell me if it is sufficient enough to instrument
> just those in ops_mem.h?  I want to make sure I am not missing any form of
> write to the memory (even it is from IO devices, which I think is taken care
> of).
>
> Thanks,
> -Shashi.
>
> On 5/17/07, Atif Hashmi <atifhashmi@gmail.com> wrote:
> >
> > Hi,
> >
> > Answering "1. Am I instrumenting all stores if I instrument the OPROTOs
> > in ops_mem.h? "
> >
> > Do you consider all updates to memory as stores? e.g. add %ebx, (%eax),
> > will also write to the memory and
> > void OPPROTO glue(glue(op_stl, MEMSUFFIX), _T0_A0)(void) or one of its
> > variant will be called.
> >
> > If you are interested in all the memory updates, then your approach is
> > correct. If you are only interested in store instructions then your approach
> > is not correct.
> >
> > Atif
> >
> > On 5/17/07, Shashidhar Mysore <shashimc@gmail.com> wrote:
> > >
> > > Hi,
> > >
> > > I want to instrument all store instructions, and for this I wrote a
> > > helper function (in helper.c) which prints out some information every
> > > time a store is executed. I call this helper function from within every
> > > store OPROTO in ops_mem.h
> > >
> > > for example:
> > > void OPPROTO glue(glue(op_stl, MEMSUFFIX), _T0_A0)(void)
> > > {
> > >     glue(stl, MEMSUFFIX)(A0, T0);
> > >     helper_print_info(A0); // MY HELPER FUNCTION
> > >     FORCE_RET();
> > > }
> > >
> > >
> > > This works just fine for me for some time, but after a while when the
> > > frequency of calls to helper_print_info increases, QEMU just hangs throwing
> > > out some information on the QEMU console. I have typed in the error message
> > > in parts below - (If you need more information, please let me know - I
> > > included  a subset just because I do not yet know how to copy-paste text
> > > from QEMU console to the host machine console)
> > >
> > > *******************************************
> > > BUG: soft lockup detected on CPU#0!
> > >
> > > Pid: 0, comm: swapper
> > > EIP: 0060:[<c027adfb>] CPU: 0
> > > EIP is at serio_interrupt+0x7f/0x18f
> > > EFLAGS: 00000286
> > > ...
> > > [c02c1b2d>] cdrom_pc_intr+0x90/0x21a
> > > ...
> > > [<c0105b1d>] do_IRQ+0x4a/0x82
> > > =======================
> > > ...
> > > [<c04242fe>] unknown_bootoption+0x0/0x1cd
> > > ****************************************
> > >
> > > QEMU hangs after throwing out the above error. However, if I switch to
> > > the Monitor and disable  my helper function, QEMU resumes back and works
> > > fine.
> > > Can somebody tell me -
> > > 1. Am I instrumenting all stores if I instrument the OPROTOs in
> > > ops_mem.h?
> > > 2. From my above example, am I instrumenting the stores with my helper
> > > function in the right way?
> > > 3. Can you please tell me why "BUG: soft lockup detected..." error
> > > shows up freezing QEMU?
> > >
> > > Looking forward to your help.
> > > Thanks in advance.
> > > -Shashi.
> > >
> >
> >
>

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