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

[Chao Yu]

On 2023/11/14 15:07, Jingbo Xu wrote:
> 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 at linux.alibaba.com>
> Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=7245
> Fixes: 49845720080d ("erofs: Convert to use bdev_open_by_path()")
> Signed-off-by: Jingbo Xu <jefflexu at linux.alibaba.com>

Reviewed-by: Chao Yu <chao at kernel.org>

Thanks,