From 20117c92bcf9c11afd64d7481d8f94fdf410726e Mon Sep 17 00:00:00 2001 From: Douglas Anderson Date: Wed, 10 Dec 2025 11:30:03 -0800 Subject: [PATCH] mfd: core: Add locking around 'mfd_of_node_list' Manipulating a list in the kernel isn't safe without some sort of mutual exclusion. Add a mutex any time we access / modify 'mfd_of_node_list' to prevent possible crashes. Cc: stable@vger.kernel.org Fixes: 466a62d7642f ("mfd: core: Make a best effort attempt to match devices with the correct of_nodes") Signed-off-by: Douglas Anderson Link: https://patch.msgid.link/20251210113002.1.I6ceaca2cfb7eb25737012b166671f516696be4fd@changeid Signed-off-by: Lee Jones --- drivers/mfd/mfd-core.c | 36 ++++++++++++++++++++++-------------- 1 file changed, 22 insertions(+), 14 deletions(-) diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c index 6925bedddc80..a30f93bf030a 100644 --- a/drivers/mfd/mfd-core.c +++ b/drivers/mfd/mfd-core.c @@ -22,6 +22,7 @@ #include static LIST_HEAD(mfd_of_node_list); +static DEFINE_MUTEX(mfd_of_node_mutex); struct mfd_of_node_entry { struct list_head list; @@ -104,9 +105,11 @@ static int mfd_match_of_node_to_dev(struct platform_device *pdev, u64 of_node_addr; /* Skip if OF node has previously been allocated to a device */ - list_for_each_entry(of_entry, &mfd_of_node_list, list) - if (of_entry->np == np) - return -EAGAIN; + scoped_guard(mutex, &mfd_of_node_mutex) { + list_for_each_entry(of_entry, &mfd_of_node_list, list) + if (of_entry->np == np) + return -EAGAIN; + } if (!cell->use_of_reg) /* No of_reg defined - allocate first free compatible match */ @@ -128,7 +131,8 @@ allocate_of_node: of_entry->dev = &pdev->dev; of_entry->np = np; - list_add_tail(&of_entry->list, &mfd_of_node_list); + scoped_guard(mutex, &mfd_of_node_mutex) + list_add_tail(&of_entry->list, &mfd_of_node_list); of_node_get(np); device_set_node(&pdev->dev, of_fwnode_handle(np)); @@ -284,11 +288,13 @@ fail_res_conflict: if (cell->swnode) device_remove_software_node(&pdev->dev); fail_of_entry: - list_for_each_entry_safe(of_entry, tmp, &mfd_of_node_list, list) - if (of_entry->dev == &pdev->dev) { - list_del(&of_entry->list); - kfree(of_entry); - } + scoped_guard(mutex, &mfd_of_node_mutex) { + list_for_each_entry_safe(of_entry, tmp, &mfd_of_node_list, list) + if (of_entry->dev == &pdev->dev) { + list_del(&of_entry->list); + kfree(of_entry); + } + } fail_alias: regulator_bulk_unregister_supply_alias(&pdev->dev, cell->parent_supplies, @@ -358,11 +364,13 @@ static int mfd_remove_devices_fn(struct device *dev, void *data) if (cell->swnode) device_remove_software_node(&pdev->dev); - list_for_each_entry_safe(of_entry, tmp, &mfd_of_node_list, list) - if (of_entry->dev == &pdev->dev) { - list_del(&of_entry->list); - kfree(of_entry); - } + scoped_guard(mutex, &mfd_of_node_mutex) { + list_for_each_entry_safe(of_entry, tmp, &mfd_of_node_list, list) + if (of_entry->dev == &pdev->dev) { + list_del(&of_entry->list); + kfree(of_entry); + } + } regulator_bulk_unregister_supply_alias(dev, cell->parent_supplies, cell->num_parent_supplies); -- 2.47.3