Re: [PATCH] bcachefs: Fix invalid shift in member_to_text()

[Hongbo Li]

On 2024/10/12 10:09, Kent Overstreet wrote:
Reported-by: syzbot+064ce437a1ad63d3f...@syzkaller.appspotmail.com
Signed-off-by: Kent Overstreet <kent.overstr...@linux.dev>
---
  fs/bcachefs/sb-members.c | 5 ++++-
  1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/bcachefs/sb-members.c b/fs/bcachefs/sb-members.c
index 02bcde3c1b02..b06ba1d0d037 100644
--- a/fs/bcachefs/sb-members.c
+++ b/fs/bcachefs/sb-members.c
@@ -247,7 +247,10 @@ static void member_to_text(struct printbuf *out,
        prt_newline(out);
  
  	prt_printf(out, "Btree allocated bitmap blocksize:\t");
-       prt_units_u64(out, 1ULL << m.btree_bitmap_shift);
+       if (m.btree_bitmap_shift < 64)
+               prt_units_u64(out, 1ULL << m.btree_bitmap_shift);
+       else
+               prt_printf(out, "(invalid shift %u)", m.btree_bitmap_shift);

I wonder why we don't check in .validate, like the former 
csum_granularity_bits does.

Thanks,
Hongbo

        prt_newline(out);
  
  	prt_printf(out, "Btree allocated bitmap:\t");