[PATCH v2 2/3] bcachefs: avoid copy from NULL printbuf when allocation failure

[Hongbo Li]

printbuf.buf may be NULL if allocation_failure is true. Check
for this prior to using it as a seq_printf source.

Fixes: fa8e94faeece ("bcachefs: Heap allocate printbufs")
Signed-off-by: David Disseldorp <dd...@suse.de>
Signed-off-by: Hongbo Li <lihongb...@huawei.com>
---
 fs/bcachefs/fs.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/fs/bcachefs/fs.c b/fs/bcachefs/fs.c
index 91fce04272a1..4dbb46e41509 100644
--- a/fs/bcachefs/fs.c
+++ b/fs/bcachefs/fs.c
@@ -2048,13 +2048,18 @@ 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;
 
        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_printf(seq, ",%s", buf.buf);
 
-       int ret = buf.allocation_failure ? -ENOMEM : 0;
+       ret = printbuf_err(&buf);
+       if (ret)
+               goto err;
+
+       seq_printf(seq, ",%s", buf.buf);
+err:
        printbuf_exit(&buf);
        return ret;
 }
-- 
2.34.1