[PATCH v2 2/4] cxl/memdev: Hold memdev lock during memdev poison injection/clear

[Li Ming]

CXL memdev poison injection/clearing debugfs interfaces are visible
before the CXL memdev endpoint initialization, If user accesses the
interfaces before cxlmd->endpoint updated, it is possible to access an
invalid endpoint in cxl_dpa_to_region().

Hold CXL memdev lock at the beginning of the interfaces, this blocks the
interfaces until CXL memdev probing completed.

The following patch will check the given endpoint validity in
cxl_dpa_to_region().

Suggested-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Reviewed-by: Dave Jiang <dave.jiang@xxxxxxxxx>
Reviewed-by: Alison Schofield <alison.schofield@xxxxxxxxx>
Signed-off-by: Li Ming <ming.li@xxxxxxxxxxxx>
---
 drivers/cxl/mem.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index fcffe24dcb42..ab88eaa31d1d 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -48,6 +48,11 @@ static int cxl_mem_dpa_show(struct seq_file *file, void *data)
 static int cxl_debugfs_poison_inject(void *data, u64 dpa)
 {
 	struct cxl_memdev *cxlmd = data;
+	int rc;
+
+	ACQUIRE(device_intr, devlock)(&cxlmd->dev);
+	if ((rc = ACQUIRE_ERR(device_intr, &devlock)))
+		return rc;
 
 	return cxl_inject_poison(cxlmd, dpa);
 }
@@ -58,6 +63,11 @@ DEFINE_DEBUGFS_ATTRIBUTE(cxl_poison_inject_fops, NULL,
 static int cxl_debugfs_poison_clear(void *data, u64 dpa)
 {
 	struct cxl_memdev *cxlmd = data;
+	int rc;
+
+	ACQUIRE(device_intr, devlock)(&cxlmd->dev);
+	if ((rc = ACQUIRE_ERR(device_intr, &devlock)))
+		return rc;
 
 	return cxl_clear_poison(cxlmd, dpa);
 }

-- 
2.43.0