[PATCH 4.4 044/138] EDAC: Correct channel count limit

Greg Kroah-Hartman
2016-08-18T14:04:24Z

From: Borislav Petkov <bp@suse.de>

commit bba142957e04c400440d2df83c1b3b2dfc42e220 upstream.

c44696fff04f ("EDAC: Remove arbitrary limit on number of channels")
lifted the arbitrary limit on memory controller channels in EDAC.
However, the dynamic channel attributes dynamic_csrow_dimm_attr and
dynamic_csrow_ce_count_attr remained 6.

This wasn't a problem except channels 6 and 7 weren't visible in sysfs
on machines with more than 6 channels after the conversion to static
attr groups with

2c1946b6d629 ("EDAC: Use static attribute groups for managing sysfs entries")

[ without that, we're exploding in edac_create_sysfs_mci_device()
because we're dereferencing out of the bounds of the
dynamic_csrow_dimm_attr array. ]

Add attributes for channels 6 and 7 along with a guard for the
future, should more channels be required and/or to sanity check for
misconfigured machines.

We still need to check against the number of channels present on the MC
first, as Thor reported.

Signed-off-by: Borislav Petkov <bp@suse.de>
Reported-by: Hironobu Ishii <ishii.hironobu@jp.fujitsu.com>
Tested-by: Thor Thayer <tthayer@opensource.altera.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/edac/edac_mc_sysfs.c | 20 +++++++++++++++++++-
1 file changed, 19 insertions(+), 1 deletion(-)

--- a/drivers/edac/edac_mc_sysfs.c
+++ b/drivers/edac/edac_mc_sysfs.c
@@ -313,7 +313,6 @@ static struct device_type csrow_attr_typ
* possible dynamic channel DIMM Label attribute files
*
*/
-
DEVICE_CHANNEL(ch0_dimm_label, S_IRUGO | S_IWUSR,
channel_dimm_label_show, channel_dimm_label_store, 0);
DEVICE_CHANNEL(ch1_dimm_label, S_IRUGO | S_IWUSR,
@@ -326,6 +325,10 @@ DEVICE_CHANNEL(ch4_dimm_label, S_IRUGO |
channel_dimm_label_show, channel_dimm_label_store, 4);
DEVICE_CHANNEL(ch5_dimm_label, S_IRUGO | S_IWUSR,
channel_dimm_label_show, channel_dimm_label_store, 5);
+DEVICE_CHANNEL(ch6_dimm_label, S_IRUGO | S_IWUSR,
+ channel_dimm_label_show, channel_dimm_label_store, 6);
+DEVICE_CHANNEL(ch7_dimm_label, S_IRUGO | S_IWUSR,
+ channel_dimm_label_show, channel_dimm_label_store, 7);

/* Total possible dynamic DIMM Label attribute file table */
static struct attribute *dynamic_csrow_dimm_attr[] = {
@@ -335,6 +338,8 @@ static struct attribute *dynamic_csrow_d
&dev_attr_legacy_ch3_dimm_label.attr.attr,
&dev_attr_legacy_ch4_dimm_label.attr.attr,
&dev_attr_legacy_ch5_dimm_label.attr.attr,
+ &dev_attr_legacy_ch6_dimm_label.attr.attr,
+ &dev_attr_legacy_ch7_dimm_label.attr.attr,
NULL
};

@@ -351,6 +356,10 @@ DEVICE_CHANNEL(ch4_ce_count, S_IRUGO,
channel_ce_count_show, NULL, 4);
DEVICE_CHANNEL(ch5_ce_count, S_IRUGO,
channel_ce_count_show, NULL, 5);
+DEVICE_CHANNEL(ch6_ce_count, S_IRUGO,
+ channel_ce_count_show, NULL, 6);
+DEVICE_CHANNEL(ch7_ce_count, S_IRUGO,
+ channel_ce_count_show, NULL, 7);

/* Total possible dynamic ce_count attribute file table */
static struct attribute *dynamic_csrow_ce_count_attr[] = {
@@ -360,6 +369,8 @@ static struct attribute *dynamic_csrow_c
&dev_attr_legacy_ch3_ce_count.attr.attr,
&dev_attr_legacy_ch4_ce_count.attr.attr,
&dev_attr_legacy_ch5_ce_count.attr.attr,
+ &dev_attr_legacy_ch6_ce_count.attr.attr,
+ &dev_attr_legacy_ch7_ce_count.attr.attr,
NULL
};

@@ -371,9 +382,16 @@ static umode_t csrow_dev_is_visible(stru

if (idx >= csrow->nr_channels)
return 0;
+
+ if (idx >= ARRAY_SIZE(dynamic_csrow_ce_count_attr) - 1) {
+ WARN_ONCE(1, "idx: %d\n", idx);
+ return 0;
+ }
+
/* Only expose populated DIMMs */
if (!csrow->channels[idx]->dimm->nr_pages)
return 0;
+
return attr->mode;
}