cxl/cdat: Fix uninitialized stack use in bandwidth gathering

cxl_endpoint_gather_bandwidth() and cxl_switch_gather_bandwidth() declare
access_coordinate arrays on the stack and rely on their helpers to fill
them. The helpers assign only the bandwidth members, and the combine step
assigns even those only when both inputs are non-zero. The latency members
are summed from stack residue on every call, and the bandwidth members
keep that residue into the region access coordinate sysfs attributes when
the endpoint CDAT reports no bandwidth.

Zero initialize the arrays. Zero is the value this code already uses for
"not reported", so an unset member now reads back as unknown rather than as
a plausible number.

Found by code inspection. Tested on a QEMU CXL topology with two endpoints
sharing a switch upstream link and HMAT generic-port coordinates for the
host bridge, which the calculation requires to run at all: with temporary
printk at the combine sites, the unpatched kernel summed 0xfefefefe, the
CONFIG_INIT_STACK_ALL_PATTERN stack filler, into the latency members, while
the patched kernel reports the CDAT latency values there.

Fixes: a5ab0de0ebaa ("cxl: Calculate region bandwidth of targets with shared upstream link")
Signed-off-by: Guixin Liu <kanie@linux.alibaba.com>
Reviewed-by: Richard Cheng <icheng@nvidia.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>
Link: https://patch.msgid.link/20260831092216.540644-2-kanie@linux.alibaba.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>

0 files changed, 0 insertions, 0 deletions