Re: [PATCH] bcachefs: avoid copy from NULL printbuf

[David Disseldorp <ddiss@suse.de>]

On Wed, 25 Sep 2024 10:21:58 +0800, Hongbo Li wrote:

> On 2024/9/24 10:52, David Disseldorp wrote:
> > printbuf.buf may be NULL if allocation_failure is set. Check for this
> > prior to using it as a seq_puts() source.
> > 
> > Fixes: fa8e94faeece1 ("bcachefs: Heap allocate printbufs")
> > Signed-off-by: David Disseldorp <ddiss@suse.de>
> > ---
> > test test
> > 
> >   fs/bcachefs/fs.c | 7 +++++--
> >   1 file changed, 5 insertions(+), 2 deletions(-)
> > 
> > diff --git a/fs/bcachefs/fs.c b/fs/bcachefs/fs.c
> > index 1aee5bafaae54..6e270bf24591d 100644
> > --- a/fs/bcachefs/fs.c
> > +++ b/fs/bcachefs/fs.c
> > @@ -1931,13 +1931,16 @@ static int bch2_show_options(struct seq_file *seq, struct dentry *root)
> >   {
> >   	struct bch_fs *c = root->d_sb->s_fs_info;
> >   	struct printbuf buf = PRINTBUF;
> > +	int ret = 0;
> >   
> >   	bch2_opts_to_text(&buf, c->opts, c, c->disk_sb.sb,
> >   			  OPT_MOUNT, OPT_HIDDEN, OPT_SHOW_MOUNT_STYLE);
> >   	printbuf_nul_terminate(&buf);
> > -	seq_puts(seq, buf.buf);
> > +	if (buf.allocation_failure)
> > +		ret = -ENOMEM;
> > +	else
> > +		seq_puts(seq, buf.buf);
> >     
> May I fix here in the last patch "bcachefs: fix incorrect show_options 
> results" in v2, and add you as co-author?

I'm fine with this being squashed in with or without a co-author tag.
However, I think they deserve separate commits given that they address
separate regressions, and fixing show_options is more critical.

Thanks, David