6.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Huang Ying <ying.huang@xxxxxxxxx>
[ Upstream commit a3483ee7e6a7f2d12b5950246f4e0ef94f4a5df0 ]
In the memory hotplug notifier function of the CXL region,
cxl_region_perf_attrs_callback(), the node ID is obtained by checking
the host address range of the region. However, the address range
information is not available when the region is registered in
devm_cxl_add_region(). Additionally, this information may be removed
or added under the protection of cxl_region_rwsem during runtime. If
the memory notifier is called for nodes other than that backed by the
region, a race condition may occur, potentially leading to a NULL
dereference or an invalid address range.
The race condition is addressed by checking the availability of the
address range information under the protection of cxl_region_rwsem. To
enhance code readability and use guard(), the relevant code has been
moved into a newly added function: cxl_region_nid().
Fixes: 067353a46d8c ("cxl/region: Add memory hotplug notifier for cxl region")
Signed-off-by: Huang, Ying <ying.huang@xxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Alison Schofield <alison.schofield@xxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Cc: Dave Jiang <dave.jiang@xxxxxxxxx>
Cc: Bharata B Rao <bharata@xxxxxxx>
Cc: Alistair Popple <apopple@xxxxxxxxxx>
Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Cc: Vishal Verma <vishal.l.verma@xxxxxxxxx>
Cc: Ira Weiny <ira.weiny@xxxxxxxxx>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Link: https://patch.msgid.link/20240618084639.1419629-2-ying.huang@xxxxxxxxx
Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/cxl/core/region.c | 19 +++++++++++++++----
1 file changed, 15 insertions(+), 4 deletions(-)
diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index 538ebd5a64fd..cd9ccdc6bc81 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -2386,14 +2386,25 @@ static bool cxl_region_update_coordinates(struct cxl_region *cxlr, int nid)
return true;
}
+static int cxl_region_nid(struct cxl_region *cxlr)
+{
+ struct cxl_region_params *p = &cxlr->params;
+ struct cxl_endpoint_decoder *cxled;
+ struct cxl_decoder *cxld;
+
+ guard(rwsem_read)(&cxl_region_rwsem);
+ cxled = p->targets[0];
+ if (!cxled)
+ return NUMA_NO_NODE;
+ cxld = &cxled->cxld;
+ return phys_to_target_node(cxld->hpa_range.start);
+}
+
static int cxl_region_perf_attrs_callback(struct notifier_block *nb,
unsigned long action, void *arg)
{
struct cxl_region *cxlr = container_of(nb, struct cxl_region,
memory_notifier);
- struct cxl_region_params *p = &cxlr->params;
- struct cxl_endpoint_decoder *cxled = p->targets[0];
- struct cxl_decoder *cxld = &cxled->cxld;
struct memory_notify *mnb = arg;
int nid = mnb->status_change_nid;
int region_nid;
@@ -2401,7 +2412,7 @@ static int cxl_region_perf_attrs_callback(struct notifier_block *nb,
if (nid == NUMA_NO_NODE || action != MEM_ONLINE)
return NOTIFY_DONE;
- region_nid = phys_to_target_node(cxld->hpa_range.start);
+ region_nid = cxl_region_nid(cxlr);
if (nid != region_nid)
return NOTIFY_DONE;
--
2.43.0
