Re: [PATCH 1/2] misc: Replace zero-length arrays with flexible array member (automatic)

[Philippe Mathieu-Daudé]

On 3/4/20 2:44 PM, Paolo Bonzini wrote:
> On 04/03/20 14:12, Philippe Mathieu-Daudé wrote:
> > hw/scsi/spapr_vscsi.c:69:29: error: field 'iu' with variable sized type
> > 'union viosrp_iu' not at the end of a struct or class is a GNU extension
> > [-Werror,-Wgnu-variable-sized-type-not-at-end]
> >      union viosrp_iu         iu;
> >                              ^
> >
> > Yay we found a bug! Thanks Gustavo :)
> >
> > union srp_iu {
> >      struct srp_login_req login_req;
> >      struct srp_login_rsp login_rsp;
> >      struct srp_login_rej login_rej;
> >      struct srp_i_logout i_logout;
> >      struct srp_t_logout t_logout;
> >      struct srp_tsk_mgmt tsk_mgmt;
> >      struct srp_cmd cmd;
> >      struct srp_rsp rsp;
> >      uint8_t reserved[SRP_MAX_IU_LEN];
> > };
>
> It's variable-sized but it's okay as long as the total size doesn't
> exceed SRP_MAX_IU_LEN.  So it's not a bug, but I agree it's a time bomb.
>   Moving the field last should work, but it would still be quite
> dangerous code.

Yeah I reached the same conclusion.

I'll send a fix for the dangerous code.
Do you want to drop this series, or only the change in 'struct srp_rsp' 
(or in all hw/scsi/srp.h). Actually I guess it makes sense I move the 
'hw/scsi/srp.h' changes with the series cleaning dangerous code.