On 11/25/20 12:50 AM, Qinglang Miao wrote:
> krealloc() may fail to expand the memory space.
Even with __GFP_NOFAIL?
* ``GFP_KERNEL | __GFP_NOFAIL`` - overrides the default allocator behavior
and all allocation requests will loop endlessly until they succeed.
This might be really dangerous especially for larger orders.
> Add sanity checks to it,
> and WARN() if that really happened.
As aside, there is no WARN added in this patch for a memory failure.
> Fixes: 771915c4f688 ("xfs: remove kmem_realloc()")
> Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
> Signed-off-by: Qinglang Miao <miaoqinglang@xxxxxxxxxx>
> ---
> fs/xfs/xfs_mount.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
> index 150ee5cb8..c07f48c32 100644
> --- a/fs/xfs/xfs_mount.c
> +++ b/fs/xfs/xfs_mount.c
> @@ -80,9 +80,13 @@ xfs_uuid_mount(
> }
>
> if (hole < 0) {
> - xfs_uuid_table = krealloc(xfs_uuid_table,
> + uuid_t *if_xfs_uuid_table;
> + if_xfs_uuid_table = krealloc(xfs_uuid_table,
> (xfs_uuid_table_size + 1) * sizeof(*xfs_uuid_table),
> GFP_KERNEL | __GFP_NOFAIL);
> + if (!if_xfs_uuid_table)
> + goto out_duplicate;
And this would emit "Filesystem has duplicate UUID" which is not correct.
But anyway, the __GFP_NOFAIL in the call makes this all moot AFAICT.
-Eric
> + xfs_uuid_table = if_xfs_uuid_table;
> hole = xfs_uuid_table_size++;
> }
> xfs_uuid_table[hole] = *uuid;
>
