ow_dev_is_visible()` ensures
   attributes only appear when hardware actually has those channels

### Stable Tree Criteria Compliance

✅ **Fixes important bug**: Yes - channels 12-15 invisible on newer AMD
systems
✅ **Small and contained**: Yes - purely mechanical additions
✅ **No side effects beyond fix**: Yes - only adds new attributes
✅ **No major architectural changes**: Yes - extends existing pattern
✅ **Minimal regression risk**: Yes - purely additive
✅ **Confined to subsystem**: Yes - only EDAC sysfs interface

### Strong Precedent

The 2022 commit `25836ce1df827` that added 12-channel support:
- Had `Cc: <stable@vger.kernel.org>`
- Had `Fixes:` tag pointing to Genoa support commit
- Used identical code pattern
- Fixed the same class of problem

**This commit is the direct continuation of that stable-backported
fix**, extending it to handle newer hardware with even more channels.

### Conclusion

This commit **should absolutely be backported** to stable trees. It
fixes a real user-visible bug on shipping AMD server hardware, follows a
proven stable-backport pattern, carries minimal risk, and is essential
for proper monitoring and diagnostics of modern high-channel-count
memory systems. The lack of an explicit `Cc: stable` tag appears to be
an oversight given the strong precedent from the nearly-identical 2022
commit.

 drivers/edac/edac_mc_sysfs.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/edac/edac_mc_sysfs.c b/drivers/edac/edac_mc_sysfs.c
index 0f338adf7d937..8689631f19053 100644
--- a/drivers/edac/edac_mc_sysfs.c
+++ b/drivers/edac/edac_mc_sysfs.c
@@ -305,6 +305,14 @@ DEVICE_CHANNEL(ch10_dimm_label, S_IRUGO | S_IWUSR,
 	channel_dimm_label_show, channel_dimm_label_store, 10);
 DEVICE_CHANNEL(ch11_dimm_label, S_IRUGO | S_IWUSR,
 	channel_dimm_label_show, channel_dimm_label_store, 11);
+DEVICE_CHANNEL(ch12_dimm_label, S_IRUGO | S_IWUSR,
+	channel_dimm_label_show, channel_dimm_label_store, 12);
+DEVICE_CHANNEL(ch13_dimm_label, S_IRUGO | S_IWUSR,
+	channel_dimm_label_show, channel_dimm_label_store, 13);
+DEVICE_CHANNEL(ch14_dimm_label, S_IRUGO | S_IWUSR,
+	channel_dimm_label_show, channel_dimm_label_store, 14);
+DEVICE_CHANNEL(ch15_dimm_label, S_IRUGO | S_IWUSR,
+	channel_dimm_label_show, channel_dimm_label_store, 15);
 
 /* Total possible dynamic DIMM Label attribute file table */
 static struct attribute *dynamic_csrow_dimm_attr[] = {
@@ -320,6 +328,10 @@ static struct attribute *dynamic_csrow_dimm_attr[] = {
 	&dev_attr_legacy_ch9_dimm_label.attr.attr,
 	&dev_attr_legacy_ch10_dimm_label.attr.attr,
 	&dev_attr_legacy_ch11_dimm_label.attr.attr,
+	&dev_attr_legacy_ch12_dimm_label.attr.attr,
+	&dev_attr_legacy_ch13_dimm_label.attr.attr,
+	&dev_attr_legacy_ch14_dimm_label.attr.attr,
+	&dev_attr_legacy_ch15_dimm_label.attr.attr,
 	NULL
 };
 
@@ -348,6 +360,14 @@ DEVICE_CHANNEL(ch10_ce_count, S_IRUGO,
 		   channel_ce_count_show, NULL, 10);
 DEVICE_CHANNEL(ch11_ce_count, S_IRUGO,
 		   channel_ce_count_show, NULL, 11);
+DEVICE_CHANNEL(ch12_ce_count, S_IRUGO,
+		   channel_ce_count_show, NULL, 12);
+DEVICE_CHANNEL(ch13_ce_count, S_IRUGO,
+		   channel_ce_count_show, NULL, 13);
+DEVICE_CHANNEL(ch14_ce_count, S_IRUGO,
+		   channel_ce_count_show, NULL, 14);
+DEVICE_CHANNEL(ch15_ce_count, S_IRUGO,
+		   channel_ce_count_show, NULL, 15);
 
 /* Total possible dynamic ce_count attribute file table */
 static struct attribute *dynamic_csrow_ce_count_attr[] = {
@@ -363,6 +383,10 @@ static struct attribute *dynamic_csrow_ce_count_attr[] = {
 	&dev_attr_legacy_ch9_ce_count.attr.attr,
 	&dev_attr_legacy_ch10_ce_count.attr.attr,
 	&dev_attr_legacy_ch11_ce_count.attr.attr,
+	&dev_attr_legacy_ch12_ce_count.attr.attr,
+	&dev_attr_legacy_ch13_ce_count.attr.attr,
+	&dev_attr_legacy_ch14_ce_count.attr.attr,
+	&dev_attr_legacy_ch15_ce_count.attr.attr,
 	NULL
 };
 
-- 
2.51.0[PATCH AUTOSEL 6.17-6.1] EDAC/mc_sysfs: Increase legacy channel support to 16Sasha Levin <sashal@kernel.org> undefinedpatches@lists.linux.dev, stable@vger.kernel.org undefined undefined undefined undefined undefined