Re: [PATCH 1/3] misc: fix valgrind complaints

[Chandan Babu R <chandanrlinux@gmail.com>]

On 09 Jan 2021 at 11:58, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@kernel.org>
>
> Zero the memory that we pass to the kernel via ioctls so that we never
> pass userspace heap/stack garbage around.  This silences valgrind
> complaints about uninitialized padding areas.
>
> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
> ---
>  libhandle/handle.c |    7 ++++++-
>  scrub/inodes.c     |    1 +
>  scrub/spacemap.c   |    2 +-
>  3 files changed, 8 insertions(+), 2 deletions(-)
>
>
> diff --git a/libhandle/handle.c b/libhandle/handle.c
> index 5c1686b3..a6b35b09 100644
> --- a/libhandle/handle.c
> +++ b/libhandle/handle.c
> @@ -235,9 +235,12 @@ obj_to_handle(
>  {
>  	char		hbuf [MAXHANSIZ];
>  	int		ret;
> -	uint32_t	handlen;
> +	uint32_t	handlen = 0;
>  	xfs_fsop_handlereq_t hreq;
>
> +	memset(&hreq, 0, sizeof(hreq));
> +	memset(hbuf, 0, MAXHANSIZ);
> +
>  	if (opcode == XFS_IOC_FD_TO_HANDLE) {
>  		hreq.fd      = obj.fd;
>  		hreq.path    = NULL;
> @@ -280,6 +283,7 @@ open_by_fshandle(
>  	if ((fsfd = handle_to_fsfd(fshanp, &path)) < 0)
>  		return -1;
>
> +	memset(&hreq, 0, sizeof(hreq));
>  	hreq.fd       = 0;
>  	hreq.path     = NULL;
>  	hreq.oflags   = rw | O_LARGEFILE;
> @@ -387,6 +391,7 @@ attr_list_by_handle(
>  	if ((fd = handle_to_fsfd(hanp, &path)) < 0)
>  		return -1;
>
> +	memset(&alhreq, 0, sizeof(alhreq));
>  	alhreq.hreq.fd       = 0;
>  	alhreq.hreq.path     = NULL;
>  	alhreq.hreq.oflags   = O_LARGEFILE;
> diff --git a/scrub/inodes.c b/scrub/inodes.c
> index 4550db83..f2bce16f 100644
> --- a/scrub/inodes.c
> +++ b/scrub/inodes.c
> @@ -129,6 +129,7 @@ scan_ag_inodes(
>  				minor(ctx->fsinfo.fs_datadev),
>  				agno);
>
> +	memset(&handle, 0, sizeof(handle));
>  	memcpy(&handle.ha_fsid, ctx->fshandle, sizeof(handle.ha_fsid));
>  	handle.ha_fid.fid_len = sizeof(xfs_fid_t) -
>  			sizeof(handle.ha_fid.fid_len);
> diff --git a/scrub/spacemap.c b/scrub/spacemap.c
> index 9653916d..9362710e 100644
> --- a/scrub/spacemap.c
> +++ b/scrub/spacemap.c
> @@ -47,7 +47,7 @@ scrub_iterate_fsmap(
>  	int			i;
>  	int			error;
>
> -	head = malloc(fsmap_sizeof(FSMAP_NR));
> +	head = calloc(1, fsmap_sizeof(FSMAP_NR));
>  	if (!head)
>  		return errno;
>

Minor nit: The "memset(head, 0, sizeof(*head))" statement following the above
call to calloc() can now be removed.

--
chandan