Re: [Qemu-devel] [PATCH 2/2] 9pfs: fix memory leak about xattr value

[Li Qiang]

Oops! I have made this patch to dress the memory leak in v9fs_xattrcreate
but forget this and make another mistake.

I mean we should call g_free for xattr.value first in xattr create.

This avoid the memory leak.

static void v9fs_xattrcreate(void *opaque)
{
  ...
    g_free(xattr_fidp->fs.xattr.value);
    xattr_fidp->fs.xattr.value = g_malloc(size);
    err = offset;

}

Should I resend this path series?

2016-10-10 17:06 GMT+08:00 Greg Kurz <address@hidden>:

> On Sat,  8 Oct 2016 22:27:08 -0700
> Li Qiang <address@hidden> wrote:
>
> > From: Li Qiang <address@hidden>
> >
> > The 'fs.xattr.value' field in V9fsFidState object doesn't consider
> > the situation that this field has been allocated previously. Every
> > time, it will be allocated directly. This leads a  host memory leak
> > issue. This patch fix this.
> >
>
> This cannot happen because v9fs_xattrwalk() always allocates this fid:
>
>     xattr_fidp = alloc_fid(s, newfid);
>     if (xattr_fidp == NULL) {
>         err = -EINVAL;
>         goto out;
>     }
>
> > Signed-off-by: Li Qiang <address@hidden>
> > ---
> >  hw/9pfs/9p.c | 7 +++++--
> >  1 file changed, 5 insertions(+), 2 deletions(-)
> >
> > diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
> > index 8751c19..3af23f9 100644
> > --- a/hw/9pfs/9p.c
> > +++ b/hw/9pfs/9p.c
> > @@ -350,6 +350,7 @@ free_out:
> >      v9fs_string_free(&fidp->fs.xattr.name);
> >  free_value:
> >      g_free(fidp->fs.xattr.value);
> > +    fidp->fs.xattr.value = NULL;
> >      return retval;
> >  }
> >
> > @@ -3191,7 +3192,8 @@ static void v9fs_xattrwalk(void *opaque)
> >          xattr_fidp->fid_type = P9_FID_XATTR;
> >          xattr_fidp->fs.xattr.copied_len = -1;
> >          if (size) {
> > -            xattr_fidp->fs.xattr.value = g_malloc(size);
> > +            xattr_fidp->fs.xattr.value = g_realloc(
> > +                xattr_fidp->fs.xattr.value, size);
> >              err = v9fs_co_llistxattr(pdu, &xattr_fidp->path,
> >                                       xattr_fidp->fs.xattr.value,
> >                                       xattr_fidp->fs.xattr.len);
> > @@ -3224,7 +3226,8 @@ static void v9fs_xattrwalk(void *opaque)
> >          xattr_fidp->fid_type = P9_FID_XATTR;
> >          xattr_fidp->fs.xattr.copied_len = -1;
> >          if (size) {
> > -            xattr_fidp->fs.xattr.value = g_malloc(size);
> > +            xattr_fidp->fs.xattr.value = g_realloc(
> > +                xattr_fidp->fs.xattr.value, size);
> >              err = v9fs_co_lgetxattr(pdu, &xattr_fidp->path,
> >                                      &name, xattr_fidp->fs.xattr.value,
> >                                      xattr_fidp->fs.xattr.len);
>
>