Re: [PATCH] f2fs: Fix gcc9 error -Werror=maybe-uninitialized

[Neil MacLeod]

Hi Daniel & Michael

I've tested the new patch (in place of my attempt) and grub is
building successfully so it looks good here!

Many thanks!
Neil

On Fri, 17 May 2019 at 13:26, Daniel Kiper <address@hidden> wrote:
>
> CC-ing address@hidden
>
> Michael, thank you for posting the patch.
>
> Neil, does it solve your problem?
>
> Daniel
>
> On Fri, May 17, 2019 at 05:00:19PM +0800, Michael Chang wrote:
> > The function grub_get_node_path could return uninitialized offset with
> > level == 0 if the block is greater than direct_index + 2*direct_blks +
> > 2*indirect_blks + dindirect_blks. The uninitialized offset is then used
> > by function grub_f2fs_get_block because level == 0 is valid and
> > meaningful return to be processed.
> >
> > The fix is to set level = -1 as return value by grub_get_node_path to
> > signify an error that the input block cannot be handled. Any caller
> > should therefore check level is negative or not before processing the
> > output.
> >
> > Reported-by: Neil MacLeod <address@hidden>
> > Signed-off-by: Michael Chang <address@hidden>
> > ---
> >  grub-core/fs/f2fs.c | 7 ++++++-
> >  1 file changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/grub-core/fs/f2fs.c b/grub-core/fs/f2fs.c
> > index 644653dbe..bb28b291b 100644
> > --- a/grub-core/fs/f2fs.c
> > +++ b/grub-core/fs/f2fs.c
> > @@ -702,7 +702,7 @@ grub_get_node_path (struct grub_f2fs_inode *inode, 
> > grub_uint32_t block,
> >    grub_uint32_t dindirect_blks = indirect_blks * NIDS_PER_BLOCK;
> >    grub_uint32_t direct_index = DEF_ADDRS_PER_INODE;
> >    int n = 0;
> > -  int level = 0;
> > +  int level = -1;
> >
> >    if (inode->i_inline & F2FS_INLINE_XATTR)
> >      direct_index -= F2FS_INLINE_XATTR_ADDRS;
> > @@ -712,6 +712,7 @@ grub_get_node_path (struct grub_f2fs_inode *inode, 
> > grub_uint32_t block,
> >    if (block < direct_index)
> >      {
> >        offset[n] = block;
> > +      level = 0;
> >        goto got;
> >      }
> >
> > @@ -860,6 +861,10 @@ grub_f2fs_get_block (grub_fshelp_node_t node, 
> > grub_disk_addr_t block_ofs)
> >    int level, i;
> >
> >    level = grub_get_node_path (inode, block_ofs, offset, noffset);
> > +
> > +  if (level < 0)
> > +    return -1;
> > +
> >    if (level == 0)
> >      return grub_le_to_cpu32 (inode->i_addr[offset[0]]);
> >
> > --
> > 2.16.4