Re: [Qemu-ppc] [Qemu-devel] [PULL 00/30] ppc-for-2.12 queue 20180306

[Greg Kurz]

On Tue, 6 Mar 2018 18:47:47 +0100
Thomas Huth <address@hidden> wrote:

> On 06.03.2018 18:28, Mark Cave-Ayland wrote:
> > On 06/03/18 16:48, Thomas Huth wrote:
> >   
> >> Something in the recent commits introduced a new way to cause unexpected
> >> aborts of QEMU:
> >>
> >> $ ppc64-softmmu/qemu-system-ppc64 -monitor stdio
> >> QEMU 2.11.50 monitor - type 'help' for more information
> >> (qemu) device_add macio-newworld
> >> Unexpected error in qemu_chr_fe_init() at
> >> /home/thuth/devel/qemu/chardev/char-fe.c:222:
> >> Device 'serial0' is in use
> >> Aborted (core dumped)
> >>
> >> Of course it does not make sense to add a macio-newworld device on the
> >> pseries machine, but QEMU should not abort in this case - it should just
> >> print an error message and continue afterwards. Any ideas how to fix
> >> this?  
> > 
> > So the backtrace from git master looks like this:
> > 
> > Thread 1 "qemu-system-ppc" received signal SIGABRT, Aborted.
> > __GI_raise (address@hidden) at ../sysdeps/unix/sysv/linux/raise.c:51
> > 
> > 
> > 51      ../sysdeps/unix/sysv/linux/raise.c: No such file or directory.
> > 
> > 
> > (gdb) bt
> > 
> > 
> > #0  __GI_raise (address@hidden) at ../sysdeps/unix/sysv/linux/raise.c:51
> > 
> > #1  0x00007fffdbd6e3fa in __GI_abort () at abort.c:89
> > 
> > 
> > #2  0x0000555555de6d86 in error_handle_fatal (errp=0x555556bdfb90
> > <error_abort>, err=0x555556ef5a00) at util/error.c:38
> > 
> > #3  0x0000555555de6eb6 in error_setv (errp=0x555556bdfb90 <error_abort>,
> > src=0x555556031ad0 "chardev/char-fe.c", line=222, func=0x555556031c50
> > <__func__.18713> "qemu_chr_fe_init", err_class=ERROR_CLASS_GENERIC_ERROR,
> >     fmt=0x555556031b50 "Device '%s' is in use", ap=0x7fffffffd010,
> > suffix=0x0) at util/error.c:71
> > 
> > #4  0x0000555555de7097 in error_setg_internal (errp=0x555556bdfb90
> > <error_abort>, src=0x555556031ad0 "chardev/char-fe.c", line=222,
> > func=0x555556031c50 <__func__.18713> "qemu_chr_fe_init",
> >     fmt=0x555556031b50 "Device '%s' is in use") at util/error.c:95
> > 
> > 
> > #5  0x0000555555d673fc in qemu_chr_fe_init (b=0x555557aef590,
> > s=0x555556de2290, errp=0x555556bdfb90 <error_abort>) at
> > chardev/char-fe.c:222
> > #6  0x0000555555af5467 in set_chr (obj=0x555557aeef80, v=0x555557960c20,
> > name=0x555555f65fc5 "chrA", opaque=0x555556658410 <escc_properties+432>,
> > errp=0x555556bdfb90 <error_abort>) at hw/core/qdev-properties-system.c:216
> > #7  0x0000555555cb326a in object_property_set (obj=0x555557aeef80,
> > v=0x555557960c20, name=0x555555f65fc5 "chrA", errp=0x555556bdfb90
> > <error_abort>) at qom/object.c:1109
> > #8  0x0000555555cb6232 in object_property_set_qobject
> > (obj=0x555557aeef80, value=0x555557960bf0, name=0x555555f65fc5 "chrA",
> > errp=0x555556bdfb90 <error_abort>) at qom/qom-qobject.c:27
> > #9  0x0000555555cb32af in object_property_set_str (obj=0x555557aeef80,
> > value=0x555556de23c0 "serial0", name=0x555555f65fc5 "chrA",
> > errp=0x555556bdfb90 <error_abort>) at qom/object.c:1117
> > #10 0x0000555555af5d94 in qdev_prop_set_chr (dev=0x555557aeef80,
> > name=0x555555f65fc5 "chrA", value=0x555556de2290) at
> > hw/core/qdev-properties-system.c:427
> > #11 0x0000555555b350a8 in macio_instance_init (obj=0x555557aec3c0) at
> > hw/misc/macio/macio.c:347
> > 
> > 
> > It seems that the error is being raised when setting the property rather
> > than during realize so I'm not sure what I can do to handle this. Any
> > thoughts?  
> 
> Does the device need to be hot-pluggable or even user_creatable at all?

FWIW, the crash also happens when the device is passed on the command line:

$ ppc64-softmmu/qemu-system-ppc64 -device macio-newworld
Unexpected error in qemu_chr_fe_init() at 
/home/greg/Work/qemu/qemu-spapr/chardev/char-fe.c:222:
qemu-system-ppc64: -device macio-newworld: Device 'serial0' is in use
Aborted (core dumped)

> It seems like it is also using serial_hds[] directly, so that is a good
> indication that it is *not* user creatable. So maybe the easiest fix is
> to simply set
> 
>       dc->user_creatable = false;
> 
> in macio_class_init() ?
> 
>  Thomas
> 
>