From 61bc4514b8e99e9733c04de028885f6fc906d628 Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Fri, 30 Oct 2026 11:22:58 -0700 Subject: [PATCH] hwmon: (peci/dimmtemp) Fix devres leak and UAF on concurrent unbind 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: 73bc1b885dae ("hwmon: peci: Add dimmtemp driver") Cc: stable@vger.kernel.org Cc: Iwona Winiarska Reviewed-by: Iwona Winiarska Signed-off-by: Guenter Roeck --- drivers/hwmon/peci/dimmtemp.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) diff --git a/drivers/hwmon/peci/dimmtemp.c b/drivers/hwmon/peci/dimmtemp.c index bd3e8715dfec..617a4cc0f65c 100644 --- a/drivers/hwmon/peci/dimmtemp.c +++ b/drivers/hwmon/peci/dimmtemp.c @@ -4,7 +4,6 @@ #include #include #include -#include #include #include #include @@ -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, };