Re: [Qemu-devel] [PATCH] Fix crash with illegal "-net nic, model=xxx" option

[Michael S. Tsirkin]

On Thu, Apr 09, 2015 at 03:48:57PM +0100, Peter Maydell wrote:
> On 9 April 2015 at 14:37, Michael S. Tsirkin <address@hidden> wrote:
> > On Thu, Apr 09, 2015 at 03:32:45PM +0200, Thomas Huth wrote:
> >> Current QEMU crashes when specifying an illegal model with the
> >> "-net nic,model=xxx" option, e.g.:
> >>
> >>  $ qemu-system-x86_64 -net nic,model=n/a
> >>  qemu-system-x86_64: Unsupported NIC model: n/a
> >>
> >>  Program received signal SIGSEGV, Segmentation fault.
> >>
> >> The gdb backtrace looks like this:
> >>
> >> 0x0000555555965fe0 in error_get_pretty (err=0x0) at util/error.c:152
> >> 152       return err->msg;
> >> (gdb) bt
> >>  0  0x0000555555965fe0 in error_get_pretty (err=0x0) at util/error.c:152
> >>  1  0x0000555555965ffd in error_report_err (err=0x0) at util/error.c:157
> >>  2  0x0000555555809c90 in pci_nic_init_nofail (nd=0x555555e49860 
> >> <nd_table>, rootbus=0x5555564409b0,
> >>     default_model=0x55555598c37b "e1000", default_devaddr=0x0) at 
> >> hw/pci/pci.c:1663
> >>  3  0x0000555555691e42 in pc_nic_init (isa_bus=0x555556f71900, 
> >> pci_bus=0x5555564409b0)
> >>     at hw/i386/pc.c:1506
> >>  4  0x000055555569396b in pc_init1 (machine=0x5555562abbf0, pci_enabled=1, 
> >> kvmclock_enabled=1)
> >>     at hw/i386/pc_piix.c:248
> >>  5  0x0000555555693d27 in pc_init_pci (machine=0x5555562abbf0) at 
> >> hw/i386/pc_piix.c:310
> >>  6  0x000055555572ddf5 in main (argc=3, argv=0x7fffffffe018, 
> >> envp=0x7fffffffe038) at vl.c:4226
> >>
> >> The problem is that pci_nic_init_nofail() does not check whether the err
> >> parameter from pci_nic_init has been set up and thus passes a NULL pointer
> >> to error_report_err(). Fix it by correctly checking the err parameter.
> >>
> >> Signed-off-by: Thomas Huth <address@hidden>
> >
> > Thanks!
> > Given that this is a legacy -net option, I'm inclined
> > to fix it post-2.3, and Cc stable.
> > Unfortunately I won't be able to do a pull request before rc3.
> 
> Since this is a pretty safe and simple change I'm happy to apply
> it direct to master if you like. Do you want to provide a reviewed-by
> tag?
> 
> thanks
> -- PMM

I reviewed the patch, and sent a tag.
I'm fine with you making the decision on whether it's
appropriate for 2.3.

-- 
MST