erofs: fix NULL dereference of dif->bdev_handle in fscache mode

Avoid NULL dereference of dif->bdev_handle, as dif->bdev_handle is NULL
in fscache mode.

 BUG: kernel NULL pointer dereference, address: 0000000000000000
 RIP: 0010:erofs_map_dev+0xbd/0x1c0
 Call Trace:
  <TASK>
  erofs_fscache_data_read_slice+0xa7/0x340
  erofs_fscache_data_read+0x11/0x30
  erofs_fscache_readahead+0xd9/0x100
  read_pages+0x47/0x1f0
  page_cache_ra_order+0x1e5/0x270
  filemap_get_pages+0xf2/0x5f0
  filemap_read+0xb8/0x2e0
  vfs_read+0x18d/0x2b0
  ksys_read+0x53/0xd0
  do_syscall_64+0x42/0xf0
  entry_SYSCALL_64_after_hwframe+0x6e/0x76

Reported-by: Yiqun Leng <yqleng@linux.alibaba.com>
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=7245
Fixes: 4984572008 ("erofs: Convert to use bdev_open_by_path()")
Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Yue Hu <huyue2@coolpad.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20231114070704.23398-1-jefflexu@linux.alibaba.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
This commit is contained in:
Jingbo Xu 2023-11-14 15:07:04 +08:00 committed by Gao Xiang
parent 914fa861e3
commit 8bd90b6ae7
1 changed files with 3 additions and 2 deletions

View File

@ -220,7 +220,7 @@ int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
up_read(&devs->rwsem);
return 0;
}
map->m_bdev = dif->bdev_handle->bdev;
map->m_bdev = dif->bdev_handle ? dif->bdev_handle->bdev : NULL;
map->m_daxdev = dif->dax_dev;
map->m_dax_part_off = dif->dax_part_off;
map->m_fscache = dif->fscache;
@ -238,7 +238,8 @@ int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
if (map->m_pa >= startoff &&
map->m_pa < startoff + length) {
map->m_pa -= startoff;
map->m_bdev = dif->bdev_handle->bdev;
map->m_bdev = dif->bdev_handle ?
dif->bdev_handle->bdev : NULL;
map->m_daxdev = dif->dax_dev;
map->m_dax_part_off = dif->dax_part_off;
map->m_fscache = dif->fscache;