6.1-stable review patch. If anyone has any objections, please let me know.
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From: Huang Ying ying.huang@intel.com
commit d6488fee66472b468ed88d265b14aa3f04dc3bdf upstream.
The decoder_populate_targets() helper walks all of the targets in a port and makes sure they can be looked up in @target_map. Where @target_map is a lookup table from target position to target id (corresponding to a cxl_dport instance). However @target_map is only responsible for conveying the active dport instances as indicated by interleave_ways.
When nr_targets > interleave_ways it results in decoder_populate_targets() walking off the end of the valid entries in @target_map. Given target_map is initialized to 0 it results in the dport lookup failing if position 0 is not mapped to a dport with an id of 0:
cxl_port port3: Failed to populate active decoder targets cxl_port port3: Failed to add decoder cxl_port port3: Failed to add decoder3.0 cxl_bus_probe: cxl_port port3: probe: -6
This bug also highlights that when the decoder's ->targets[] array is written in cxl_port_setup_targets() it is missing a hold of the targets_lock to synchronize against sysfs readers of the target list. A fix for that is saved for a later patch.
Fixes: a5c258021689 ("cxl/bus: Populate the target list at decoder create") Cc: stable@vger.kernel.org Signed-off-by: Huang, Ying ying.huang@intel.com [djbw: rewrite the changelog, find the Fixes: tag] Co-developed-by: Dan Williams dan.j.williams@intel.com Reviewed-by: Alison Schofield alison.schofield@intel.com Reviewed-by: Dave Jiang dave.jiang@intel.com Signed-off-by: Dan Williams dan.j.williams@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/cxl/core/port.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/cxl/core/port.c +++ b/drivers/cxl/core/port.c @@ -1403,7 +1403,7 @@ static int decoder_populate_targets(stru return -EINVAL;
write_seqlock(&cxlsd->target_lock); - for (i = 0; i < cxlsd->nr_targets; i++) { + for (i = 0; i < cxlsd->cxld.interleave_ways; i++) { struct cxl_dport *dport = find_dport(port, target_map[i]);
if (!dport) {