[PATCH v2 1/2] ACPI: scan: Print the offline failure message in acpi_bus_offline()

[Sasha Levin]

When a physical node of an ACPI device being hot-removed cannot be
offlined, acpi_bus_offline() passes the physical device back to
acpi_scan_try_to_offline() through ret_p and the latter prints
"Offline failed." for it after the namespace walk.  By then
physical_node_lock is not held anymore, so the device may have been
unbound from its ACPI companion and freed in the meantime.

Print the message in acpi_bus_offline() when device_offline() fails in
the second pass, while physical_node_lock keeps the device bound to its
ACPI companion and so the reference taken by acpi_bind_one() is still
held.  acpi_scan_try_to_offline() only needs to know that something
could not be offlined, so pass the ACPI device back through ret_p
instead, like in the "Offline disabled." case.

Fixes: 303bfdb1a14d ("ACPI / scan: Add second pass of companion offlining to hot-remove code")
Suggested-by: Rafael J. Wysocki <rafael@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/acpi/scan.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 0b17a7e519569..07d32f118631e 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -165,8 +165,9 @@ static acpi_status acpi_bus_offline(acpi_handle handle, u32 lvl, void *data,
 		if (ret >= 0) {
 			pn->put_online = !ret;
 		} else {
-			*ret_p = pn->dev;
+			*ret_p = &device->dev;
 			if (second_pass) {
+				dev_warn(pn->dev, "Offline failed.\n");
 				status = AE_ERROR;
 				break;
 			}
@@ -235,7 +236,6 @@ static int acpi_scan_try_to_offline(struct acpi_device *device)
 					 (void **)&errdev);
 
 		if (errdev) {
-			dev_warn(errdev, "Offline failed.\n");
 			acpi_bus_online(handle, 0, NULL, NULL);
 			acpi_walk_namespace(ACPI_TYPE_ANY, handle,
 					    ACPI_UINT32_MAX, acpi_bus_online,
-- 
2.53.0