2022-05-23 06:23:08

by Peng Liu

Subject: [PATCH v2 0/2] null_blk: fix wrong use of nr_online_nodes

Helper node_available() is introduced to judge whether a node can be
used, and it is used to fix the wrong use of nr_online_nodes when
numa node is sparse.

v1->v2:
Modify comments as suggested by Bjorn Helgaas.

Peng Liu (2):
numa: create node_available() helper
null_blk: fix wrong use of nr_online_nodes

arch/ia64/hp/common/sba_iommu.c | 2 +-
arch/x86/pci/acpi.c | 2 +-
drivers/acpi/arm64/iort.c | 2 +-
drivers/block/null_blk/main.c | 45 ++++++++++++++++++++-------------
drivers/pci/pci-sysfs.c | 2 +-
include/linux/nodemask.h | 3 +++
mm/mempolicy.c | 2 +-
7 files changed, 36 insertions(+), 22 deletions(-)

--
2.25.1

2022-05-23 08:01:14

by Peng Liu

Subject: [PATCH v2 2/2] null_blk: fix wrong use of nr_online_nodes

Certain systems are designed to have sparse/discontiguous nodes,
a valid node may be greater than nr_online_nodes. So, the use of
"nid >= nr_online_nodes" to judge if a node is online is wrong.

Node id is a basic parameter of the system, a user-configured node
must be checked as early as possible. Otherwise, it may cause panic
when calling some vulnerable functions such as node_online which
will cause panic if a very big node is received.

Check g_home_node once users config it, and use node_available to
make node-checking compatible with sparse/discontiguous nodes.

Fixes: 7ff684a683d7 ("null_blk: prevent crash from bad home_node value")
Signed-off-by: Peng Liu <[email protected]>
Suggested-by: Davidlohr Bueso <[email protected]>
---
drivers/block/null_blk/main.c | 45 ++++++++++++++++++++++-------------
1 file changed, 28 insertions(+), 17 deletions(-)

diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index c441a4972064..312903f3a09e 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -97,7 +97,33 @@ module_param_named(poll_queues, g_poll_queues, int, 0444);
MODULE_PARM_DESC(poll_queues, "Number of IOPOLL submission queues");

static int g_home_node = NUMA_NO_NODE;
-module_param_named(home_node, g_home_node, int, 0444);
+
+static int null_param_store_val(const char *str, int *val, int min, int max)
+{
+ int ret, new_val;
+
+ ret = kstrtoint(str, 10, &new_val);
+ if (ret)
+ return -EINVAL;
+
+ if (new_val < min || new_val > max)
+ return -EINVAL;
+
+ *val = new_val;
+ return 0;
+}
+
+static int null_set_home_node(const char *str, const struct kernel_param *kp)
+{
+ return null_param_store_val(str, &g_home_node, 0, MAX_NUMNODES - 1);
+}
+
+static const struct kernel_param_ops null_home_node_param_ops = {
+ .set = null_set_home_node,
+ .get = param_get_int,
+};
+
+device_param_cb(home_node, &null_home_node_param_ops, &g_home_node, 0444);
MODULE_PARM_DESC(home_node, "Home node for the device");

#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
@@ -120,21 +146,6 @@ MODULE_PARM_DESC(init_hctx, "Fault injection to fail hctx init. init_hctx=<inter

static int g_queue_mode = NULL_Q_MQ;

-static int null_param_store_val(const char *str, int *val, int min, int max)
-{
- int ret, new_val;
-
- ret = kstrtoint(str, 10, &new_val);
- if (ret)
- return -EINVAL;
-
- if (new_val < min || new_val > max)
- return -EINVAL;
-
- *val = new_val;
- return 0;
-}
-
static int null_set_queue_mode(const char *str, const struct kernel_param *kp)
{
return null_param_store_val(str, &g_queue_mode, NULL_Q_BIO, NULL_Q_MQ);
@@ -2107,7 +2118,7 @@ static int __init null_init(void)
g_max_sectors = BLK_DEF_MAX_SECTORS;
}

- if (g_home_node != NUMA_NO_NODE && g_home_node >= nr_online_nodes) {
+ if (!node_available(g_home_node)) {
pr_err("invalid home_node value\n");
g_home_node = NUMA_NO_NODE;
}
--
2.25.1