From: "Rafael J. Wysocki" <[email protected]>
If acpi_nfit_init() fails after adding the acpi_desc object to the
acpi_descs list, that object is never removed from that list because
the acpi_nfit_shutdown() devm action is not added for the NFIT device
in that case. Next, the acpi_nfit_init() failure causes
acpi_nfit_probe() to fail, the acpi_desc object is freed, and a
dangling pointer is left behind in the acpi_descs. Any subsequent
ACPI Machine Check Exception will trigger nfit_handle_mce() which
iterates over acpi_descs and so a use-after-free will occur.
Moreover, if acpi_nfit_probe() returns 0 after installing a notify
handler for the NFIT device and without allocating the acpi_desc
object and setting the NFIT device's driver data pointer, the
acpi_desc object will be allocated by acpi_nfit_update_notify()
and acpi_nfit_init() will be called to initialize it. Regardless
of whether or not acpi_nfit_init() fails in that case, the
acpi_nfit_shutdown() devm action is not added for the NFIT device
and acpi_desc is never removed from the acpi_descs list. If the
acpi_desc object is freed subsequently on driver removal, any
subsequent ACPI MCE will lead to a use-after-free like in the
previous case.
To address the first issue mentioned above, make acpi_nfit_probe()
call acpi_nfit_shutdown() directly on acpi_nfit_init() failures and
to address the other one, add a remove callback to the driver and
make it call acpi_nfit_shutdown(). Also, since it is now possible to
pass NULL to acpi_nfit_shutdown() or the acpi_desc object passed to it
may not have been initialized, add checks against NULL for acpi_desc and
its nvdimm_bus field to that function and make acpi_nfit_unregister()
clear the latter after unregistering the NVDIMM bus.
Fixes: a61fe6f7902e ("nfit, tools/testing/nvdimm: unify common init for
acpi_nfit_desc")
Fixes: fbabd829fe76 ("acpi, nfit: fix module unload vs workqueue shutdown race")
Signed-off-by: Rafael J. Wysocki <[email protected]>
Cc: All applicable <[email protected]>
---
drivers/acpi/nfit/core.c | 18 +++++++++++++++---
1 file changed, 15 insertions(+), 3 deletions(-)
diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index 8024cd3cad14..01c73be0bd00 100644
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -3069,6 +3069,8 @@ static void acpi_nfit_unregister(void *data)
struct acpi_nfit_desc *acpi_desc = data;
nvdimm_bus_unregister(acpi_desc->nvdimm_bus);
+ /* The nvdimm_bus object may have been freed, so clear the pointer. */
+ acpi_desc->nvdimm_bus = NULL;
}
int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz)
@@ -3301,7 +3303,10 @@ static void acpi_nfit_notify(acpi_handle handle, u32
event, void *data)
void acpi_nfit_shutdown(void *data)
{
struct acpi_nfit_desc *acpi_desc = data;
- struct device *bus_dev = to_nvdimm_bus_dev(acpi_desc->nvdimm_bus);
+ struct device *bus_dev;
+
+ if (!acpi_desc || !acpi_desc->nvdimm_bus)
+ return;
/*
* Destruct under acpi_desc_lock so that nfit_handle_mce does not
@@ -3316,6 +3321,7 @@ void acpi_nfit_shutdown(void *data)
mutex_unlock(&acpi_desc->init_mutex);
cancel_delayed_work_sync(&acpi_desc->dwork);
+ bus_dev = to_nvdimm_bus_dev(acpi_desc->nvdimm_bus);
/*
* Bounce the nvdimm bus lock to make sure any in-flight
* acpi_nfit_ars_rescan() submissions have had a chance to
@@ -3388,9 +3394,14 @@ static int acpi_nfit_probe(struct platform_device *pdev)
sz - sizeof(struct acpi_table_nfit));
if (rc)
- return rc;
+ acpi_nfit_shutdown(acpi_desc);
- return devm_add_action_or_reset(dev, acpi_nfit_shutdown, acpi_desc);
+ return rc;
+}
+
+static void acpi_nfit_remove(struct platform_device *pdev)
+{
+ acpi_nfit_shutdown(platform_get_drvdata(pdev));
}
static void acpi_nfit_update_notify(struct device *dev, acpi_handle handle)
@@ -3474,6 +3485,7 @@ MODULE_DEVICE_TABLE(acpi, acpi_nfit_ids);
static struct platform_driver acpi_nfit_driver = {
.probe = acpi_nfit_probe,
+ .remove = acpi_nfit_remove,
.driver = {
.name = "acpi-nfit",
.acpi_match_table = acpi_nfit_ids,
--
2.51.0
