This is a note to let you know that I've just added the patch titled
cxl/port: Fix decoder initialization when nr_targets > interleave_ways
to the 6.7-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
cxl-port-fix-decoder-initialization-when-nr_targets-interleave_ways.patch
and it can be found in the queue-6.7 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From d6488fee66472b468ed88d265b14aa3f04dc3bdf Mon Sep 17 00:00:00 2001
From: Huang Ying <ying.huang@xxxxxxxxx>
Date: Fri, 8 Dec 2023 11:06:36 +0800
Subject: cxl/port: Fix decoder initialization when nr_targets > interleave_ways
From: Huang Ying <ying.huang@xxxxxxxxx>
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@xxxxxxxxxxxxxxx>
Signed-off-by: Huang, Ying <ying.huang@xxxxxxxxx>
[djbw: rewrite the changelog, find the Fixes: tag]
Co-developed-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Reviewed-by: Alison Schofield <alison.schofield@xxxxxxxxx>
Reviewed-by: Dave Jiang <dave.jiang@xxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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
@@ -1644,7 +1644,7 @@ 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) {
Patches currently in stable-queue which might be from ying.huang@xxxxxxxxx are
queue-6.7/cxl-port-fix-decoder-initialization-when-nr_targets-interleave_ways.patch
