Re: [Qemu-devel] [PATCH v2 3/4] memory-backend-file: improve error handling

[Hu Tao]

On Tue, Jun 17, 2014 at 12:03:13PM +0200, Igor Mammedov wrote:
> On Mon, 16 Jun 2014 18:05:43 +0800
> Hu Tao <address@hidden> wrote:
> 
> > This patch fixes two problems of memory-backend-file:
> > 
> > 1. If user adds a memory-backend-file object using object_add command,
> >    specifying a non-existing directory for property mem-path, qemu
> >    will core dump with message:
> > 
> >      /nonexistingdir: No such file or directory
> >      Bad ram offset fffffffffffff000
> >      Aborted (core dumped)
> > 
> > 2. If user adds a memory-backend-file object using object_add command,
> >    specifying a size that is less than huge page size, qemu
> >    will core dump with message:
> > 
> >      Bad ram offset fffffffffffff000
> >      Aborted (core dumped)
> > 
> > Signed-off-by: Hu Tao <address@hidden>
> > ---
> >  exec.c | 26 ++++++++++++++++++--------
> >  1 file changed, 18 insertions(+), 8 deletions(-)
> > 
> > diff --git a/exec.c b/exec.c
> > index 8705cc5..a6afb4d 100644
> > --- a/exec.c
> > +++ b/exec.c
> [...]
> > @@ -1308,7 +1311,14 @@ ram_addr_t qemu_ram_alloc_from_file(ram_addr_t size, 
> > MemoryRegion *mr,
> >          return -1;
> >      }
> >  
> > -    return ram_block_add(new_block);
> > +    addr = ram_block_add(new_block);
> > +    if (addr == -1) {
> how this hunk is relevant to commit message?
> 
> and more important in what case ram_block_add() returns -1?

See patch 03 int v1(titled [PATCH RFC 3/4] exec: don't exit unconditionally if 
failed to allocate memory)
It is not included in this version but we'll fix it after the merge.

> 
> > +        g_free(new_block);
> > +        error_setg(errp, "failed to allocate memory\n");
> > +        return -1;
> > +    }
> > +
> > +    return addr;
> >  }
> >  #endif
> >