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hwmon: (peci/dimmtemp) Fix devres leak and UAF on concurrent unbind

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When a peci_dimmtemp device is unbound concurrently with its delayed
initialization work (detect_work), newly allocated devm resources and
the hwmon device are leaked, leading to a use-after-free when reading
the lingering hwmon sysfs attributes.

In peci_dimmtemp_probe(), detect_work is registered for cancellation via
devm_delayed_work_autocancel(). During driver detach, devres_release_all()
first moves all existing entries from dev->devres_head onto a local todo
list before invoking their release callbacks in reverse order. If
create_dimm_temp_info_delayed() is already running when
devm_delayed_work_drop() calls cancel_delayed_work_sync(),
create_dimm_temp_info() can allocate dimmtemp_label strings via
devm_kzalloc()/devm_kasprintf() and register the hwmon device via
devm_hwmon_device_register_with_info(), appending new devres entries to
the now-empty dev->devres_head. Once the work finishes,
devres_release_all() frees priv and priv->name from the local todo list
without re-evaluating dev->devres_head, leaving the late devres
allocations and registered hwmon device behind with a dangling priv
pointer.

Cancel detect_work synchronously in a driver .remove() callback instead
of relying on devm_delayed_work_autocancel() so that the work is fully
drained before devres_release_all() detaches dev->devres_head, allowing
any devm resources registered by the delayed work to be released in
proper reverse order. Also only schedule detect_work when
check_populated_dimms() returns -EAGAIN so that probe failure paths do
not leave delayed work pending.

Fixes: 73bc1b885d ("hwmon: peci: Add dimmtemp driver")
Cc: stable@vger.kernel.org
Cc: Iwona Winiarska <iwona.winiarska@intel.com>
Reviewed-by: Iwona Winiarska <iwona.winiarska@intel.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Guenter Roeck 2026-10-30 11:22:58 -07:00
parent c4a01c2a80
commit 61bc4514b8
1 changed files with 14 additions and 7 deletions
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21
drivers/hwmon/peci/dimmtemp.c
View File

@ -4,7 +4,6 @@
#include <linux/auxiliary_bus.h>
#include <linux/bitfield.h>
#include <linux/bitops.h>
#include <linux/devm-helpers.h>
#include <linux/hwmon.h>
#include <linux/jiffies.h>
#include <linux/module.h>
@ -326,11 +325,13 @@ static int create_dimm_temp_info(struct peci_dimmtemp *priv)
if (ret == -ENODEV) {
dev_dbg(priv->dev, "No DIMMs found\n");
return 0;
} else if (ret) {
}
if (ret == -EAGAIN) {
schedule_delayed_work(&priv->detect_work, DIMM_MASK_CHECK_DELAY_JIFFIES);
dev_dbg(priv->dev, "Deferred populating DIMM temp info\n");
return ret;
}
if (ret)
return ret;
channels = priv->gen_info->chan_rank_max * priv->gen_info->dimm_idx_max;
@ -398,10 +399,8 @@ static int peci_dimmtemp_probe(struct auxiliary_device *adev, const struct auxil
"Unexpected PECI revision %#x, some features may be unavailable\n",
peci_dev->info.peci_revision);
ret = devm_delayed_work_autocancel(priv->dev, &priv->detect_work,
create_dimm_temp_info_delayed);
if (ret)
return ret;
auxiliary_set_drvdata(adev, priv);
INIT_DELAYED_WORK(&priv->detect_work, create_dimm_temp_info_delayed);
ret = create_dimm_temp_info(priv);
if (ret && ret != -EAGAIN) {
@ -412,6 +411,13 @@ static int peci_dimmtemp_probe(struct auxiliary_device *adev, const struct auxil
return 0;
}
static void peci_dimmtemp_remove(struct auxiliary_device *adev)
{
struct peci_dimmtemp *priv = auxiliary_get_drvdata(adev);
cancel_delayed_work_sync(&priv->detect_work);
}
static int
read_thresholds_hsx(struct peci_dimmtemp *priv, int dimm_order, int chan_rank, u32 *data)
{
@ -665,6 +671,7 @@ MODULE_DEVICE_TABLE(auxiliary, peci_dimmtemp_ids);
static struct auxiliary_driver peci_dimmtemp_driver = {
.probe = peci_dimmtemp_probe,
.remove = peci_dimmtemp_remove,
.id_table = peci_dimmtemp_ids,
};