On 11/3/2022 5:30 PM, Dan Williams wrote:
Some regions may not have any address space allocated. Skip them when
validating HPA order otherwise a crash like the following may result:
devm_cxl_add_region: cxl_acpi cxl_acpi.0: decoder3.4: created region9
BUG: kernel NULL pointer dereference, address: 0000000000000000
[..]
RIP: 0010:store_targetN+0x655/0x1740 [cxl_core]
[..]
Call Trace:
<TASK>
kernfs_fop_write_iter+0x144/0x200
vfs_write+0x24a/0x4d0
ksys_write+0x69/0xf0
do_syscall_64+0x3a/0x90
store_targetN+0x655/0x1740:
alloc_region_ref at drivers/cxl/core/region.c:676
(inlined by) cxl_port_attach_region at drivers/cxl/core/region.c:850
(inlined by) cxl_region_attach at drivers/cxl/core/region.c:1290
(inlined by) attach_target at drivers/cxl/core/region.c:1410
(inlined by) store_targetN at drivers/cxl/core/region.c:1453
Cc: <stable@xxxxxxxxxxxxxxx>
Fixes: 384e624bb211 ("cxl/region: Attach endpoint decoders")
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Reviewed-by: Dave Jiang <dave.jiang@xxxxxxxxx>
---
drivers/cxl/core/region.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index bb6f4fc84a3f..d26ca7a6beae 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -658,6 +658,9 @@ static struct cxl_region_ref *alloc_region_ref(struct cxl_port *port,
xa_for_each(&port->regions, index, iter) {
struct cxl_region_params *ip = &iter->region->params;
+ if (!ip->res)
+ continue;
+
if (ip->res->start > p->res->start) {
dev_dbg(&cxlr->dev,
"%s: HPA order violation %s:%pr vs %pr\n",
