Re: [BUG] xfs: NULL pointer dereference in xfs_buf.h: xfs_buf_daddr()

[Christoph Hellwig <hch@infradead.org>]

On Tue, Nov 18, 2025 at 07:06:14PM +0800, 李天宇 wrote:
> The kernel reports a kernel NULL pointer dereference when the sys_mount is called. This is triggered by the statement b_maps[0], where b_maps is NULL.
> 
> This bug was discovered through a fuzzing framework on Linux v6.2

Linux 6.2 is ancient (Feb 2023), and the buffer cache code has seen a
major rewrite since:

ch@brick:~/work/linux$ git diff v6.2..HEAD fs/xfs/xfs_buf.[ch] | diffstat
 xfs_buf.c | 1651 +++++++++++++++++++++++++++++++++++++++-----------------------------------------------------
  xfs_buf.h |   96 +++--
2 files changed, 768 insertions(+), 979 deletions(-)

hch@brick:~/work/linux$ wc -l fs/xfs/xfs_buf.[ch]
 2132 fs/xfs/xfs_buf.c
  391 fs/xfs/xfs_buf.h
 2523 total

so I'm not sure how relevant this report is, especially without a good
report.