commit f72e77c33e4b5657af35125e75bab249256030f3 upstream.

In various places in the kernel, we modify the fwnode "flags" member
by doing either:
  fwnode->flags |= SOME_FLAG;
  fwnode->flags &= ~SOME_FLAG;

This type of modification is not thread-safe. If two threads are both
mucking with the flags at the same time then one can clobber the
other.

While flags are often modified while under the "fwnode_link_lock",
this is not universally true.

Create some accessor functions for setting, clearing, and testing the
FWNODE flags and move all users to these accessor functions. New
accessor functions use set_bit() and clear_bit(), which are
thread-safe.

Cc: stable@vger.kernel.org
Fixes: c2c724c868c4 ("driver core: Add fw_devlink_parse_fwtree()")
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
Reviewed-by: Saravana Kannan <saravanak@kernel.org>
Link: https://patch.msgid.link/20260317090112.v2.1.I0a4d03104ecd5103df3d76f66c8d21b1d15a2e38@changeid
[ Fix fwnode_clear_flag() argument alignment, restore dropped blank
  line in fwnode_dev_initialized(), and remove unnecessary parentheses
  around fwnode_test_flag() calls. - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit a2225b6e834a838ae3c93709760edc0a169eb2f2 upstream.

The moment we link a "struct device" into the list of devices for the
bus, it's possible probe can happen. This is because another thread
can load the driver at any time and that can cause the device to
probe. This has been seen in practice with a stack crawl that looks
like this [1]:

  really_probe()
  __driver_probe_device()
  driver_probe_device()
  __driver_attach()
  bus_for_each_dev()
  driver_attach()
  bus_add_driver()
  driver_register()
  __platform_driver_register()
  init_module() [some module]
  do_one_initcall()
  do_init_module()
  load_module()
  __arm64_sys_finit_module()
  invoke_syscall()

As a result of the above, it was seen that device_links_driver_bound()
could be called for the device before "dev->fwnode->dev" was
assigned. This prevented __fw_devlink_pickup_dangling_consumers() from
being called which meant that other devices waiting on our driver's
sub-nodes were stuck deferring forever.

It's believed that this problem is showing up suddenly for two
reasons:
1. Android has recently (last ~1 year) implemented an optimization to
   the order it loads modules [2]. When devices opt-in to this faster
   loading, modules are loaded one-after-the-other very quickly. This
   is unlike how other distributions do it. The reproduction of this
   problem has only been seen on devices that opt-in to Android's
   "parallel module loading".
2. Android devices typically opt-in to fw_devlink, and the most
   noticeable issue is the NULL "dev->fwnode->dev" in
   device_links_driver_bound(). fw_devlink is somewhat new code and
   also not in use by all Linux devices.

Even though the specific symptom where "dev->fwnode->dev" wasn't
assigned could be fixed by moving that assignment higher in
device_add(), other parts of device_add() (like the call to
device_pm_add()) are also important to run before probe. Only moving
the "dev->fwnode->dev" assignment would likely fix the current
symptoms but lead to difficult-to-debug problems in the future.

Fix the problem by preventing probe until device_add() has run far
enough that the device is ready to probe. If somehow we end up trying
to probe before we're allowed, __driver_probe_device() will return
-EPROBE_DEFER which will make certain the device is noticed.

In the race condition that was seen with Android's faster module
loading, we will temporarily add the device to the deferred list and
then take it off immediately when device_add() probes the device.

Instead of adding another flag to the bitfields already in "struct
device", instead add a new "flags" field and use that. This allows us
to freely change the bit from different thread without worrying about
corrupting nearby bits (and means threads changing other bit won't
corrupt us).

[1] Captured on a machine running a downstream 6.6 kernel
[2] https://cs.android.com/android/platform/superproject/main/+/main:system/core/libmodprobe/libmodprobe.cpp?q=LoadModulesParallel

Cc: stable@vger.kernel.org
Fixes: 2023c610dc54 ("Driver core: add new device to bus's list before probing")
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Reviewed-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patch.msgid.link/20260406162231.v5.1.Id750b0fbcc94f23ed04b7aecabcead688d0d8c17@changeid
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

[ Upstream commit cb3d1049f4ea77d5ad93f17d8ac1f2ed4da70501 ]

Currently, there are 12 busses (including platform and PCI) that
duplicate the driver_override logic for their individual devices.

All of them seem to be prone to the bug described in [1].

While this could be solved for every bus individually using a separate
lock, solving this in the driver-core generically results in less (and
cleaner) changes overall.

Thus, move driver_override to struct device, provide corresponding
accessors for busses and handle locking with a separate lock internally.

In particular, add device_set_driver_override(),
device_has_driver_override(), device_match_driver_override() and
generalize the sysfs store() and show() callbacks via a driver_override
feature flag in struct bus_type.

Until all busses have migrated, keep driver_set_override() in place.

Note that we can't use the device lock for the reasons described in [2].

Link: https://bugzilla.kernel.org/show_bug.cgi?id=220789 [1]
Link: https://lore.kernel.org/driver-core/DGRGTIRHA62X.3RY09D9SOK77P@kernel.org/ [2]
Tested-by: Gui-Dong Han <hanguidong02@gmail.com>
Co-developed-by: Gui-Dong Han <hanguidong02@gmail.com>
Signed-off-by: Gui-Dong Han <hanguidong02@gmail.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/20260303115720.48783-2-dakr@kernel.org
[ Use dev->bus instead of sp->bus for consistency; fix commit message to
  refer to the struct bus_type's driver_override feature flag. - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Stable-dep-of: 2b38efc05bf7 ("driver core: platform: use generic driver_override infrastructure")
Signed-off-by: Sasha Levin <sashal@kernel.org>

Due to the wider deployment of the ->sync_state() support, for PM domains
for example, we are receiving reports about the sync_state() pending
message that is being logged in fw_devlink_dev_sync_state(). In particular
as it's printed at the warning level, which is questionable.

Even if it certainly is useful to know that the ->sync_state() condition
could not be met, there may be nothing wrong with it. For example, a driver
may be built as module and are still waiting to be initialized/probed. For
this reason let's move to the info level for now.

Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reported-by: Sebin Francis <sebin.francis@ti.com>
Reported-by: Diederik de Haas <didi.debian@cknow.org>
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Dhruva Gole <d-gole@ti.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Acked-by: Saravana Kannan <saravanak@google.com>
Reviewed-by: Sebin Francis <sebin.francis@ti.com>
Tested-by: Sebin Francis <sebin.francis@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Merge runtime PM framework updates and a core power management code fix
for 6.18-rc1:

 - Make pm_runtime_put*() family of functions return 1 when the
   given device is already suspended which is consistent with the
   documentation (Brian Norris)

 - Add basic kunit tests for runtime PM API contracts and update return
   values in kerneldoc coments for the runtime PM API (Brian Norris,
   Dan Carpenter)

 - Add auto-cleanup macros for runtime PM "resume and get" and "get
   without resume" operations, use one of them in the PCI core and
   drop the existing "free" macro introduced for similar purpose, but
   somewhat cumbersome to use (Rafael Wysocki)

 - Make the core power management code avoid waiting on device links
   marked as SYNC_STATE_ONLY which is consistent with the handling of
   those device links elsewhere (Pin-yen Lin)

* pm-core:
  PM: sleep: Do not wait on SYNC_STATE_ONLY device links

* pm-runtime:
  PM: runtime: Fix error checking for kunit_device_register()
  PM: runtime: Introduce one more usage counter guard
  PM: runtime: Drop DEFINE_FREE() for pm_runtime_put()
  PCI/sysfs: Use runtime PM guard macro for auto-cleanup
  PM: runtime: Add auto-cleanup macros for "resume and get" operations
  PM: runtime: Update kerneldoc return codes
  PM: runtime: Make put{,_sync}() return 1 when already suspended
  PM: runtime: Add basic kunit tests for API contracts

Device links with DL_FLAG_SYNC_STATE_ONLY should not affect system
suspend and resume, and functions like device_reorder_to_tail() and
device_link_add() don't try to reorder the consumers with that flag.

However, dpm_wait_for_consumers() and dpm_wait_for_suppliers() don't
check thas flag before triggering dpm_wait(), leading to potential hang
during suspend/resume.

This can be reproduced on MT8186 Corsola Chromebook with devicetree like:

usb-a-connector {
        compatible = "usb-a-connector";
        port {
                usb_a_con: endpoint {
                        remote-endpoint = <&usb_hs>;
                };
        };
};

usb_host {
        compatible = "mediatek,mt8186-xhci", "mediatek,mtk-xhci";
        port {
                usb_hs: endpoint {
                        remote-endpoint = <&usb_a_con>;
                };
        };
};

In this case, the two nodes form a cycle and a SYNC_STATE_ONLY devlink
between usb_host (supplier) and usb-a-connector (consumer) is created.

Address this by exporting device_link_flag_is_sync_state_only() and
making dpm_wait_for_consumers() and dpm_wait_for_suppliers() use it
when deciding if dpm_wait() should be called.

Fixes: 05ef983e0d65a ("driver core: Add device link support for SYNC_STATE_ONLY flag")
Signed-off-by: Pin-yen Lin <treapking@chromium.org>
Link: https://patch.msgid.link/20250926102320.4053167-1-treapking@chromium.org
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Fix the order of the kernel-doc parameters in device_find_child() and
device_for_each_child*() functions to match the actual functions signature.

No functional changes.

Signed-off-by: Gil Fine <gil.fine@linux.intel.com>
Link: https://lore.kernel.org/r/20250831194930.2063390-1-gil.fine@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit 9a4681a485ee ("driver core: Export get_dev_from_fwnode()") made
get_dev_from_fwnode() publicly available, but didn't document the
guarantees a caller must uphold:

get_dev_from_fwnode() obtains a reference count from the device pointer
stored in a struct fwnode_handle. While having its own reference count,
struct fwnode_handle does not keep a reference count of the device it
has a pointer to.

Consequently, a caller must guarantee that it is impossible that the
last device reference is dropped and the device is released concurrently
while calling get_dev_from_fwnode(), otherwise this is a potential UAF
and hence a bug.

Thus, document this potential race condition for get_dev_from_fwnode().

Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Saravana Kannan <saravanak@google.com>
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20250829205911.33142-1-dakr@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Pull driver core updates from Danilo Krummrich:
 "debugfs:
   - Remove unneeded debugfs_file_{get,put}() instances
   - Remove last remnants of debugfs_real_fops()
   - Allow storing non-const void * in struct debugfs_inode_info::aux

  sysfs:
   - Switch back to attribute_group::bin_attrs (treewide)
   - Switch back to bin_attribute::read()/write() (treewide)
   - Constify internal references to 'struct bin_attribute'

  Support cache-ids for device-tree systems:
   - Add arch hook arch_compact_of_hwid()
   - Use arch_compact_of_hwid() to compact MPIDR values on arm64

  Rust:
   - Device:
       - Introduce CoreInternal device context (for bus internal methods)
       - Provide generic drvdata accessors for bus devices
       - Provide Driver::unbind() callbacks
       - Use the infrastructure above for auxiliary, PCI and platform
       - Implement Device::as_bound()
       - Rename Device::as_ref() to Device::from_raw() (treewide)
       - Implement fwnode and device property abstractions
       - Implement example usage in the Rust platform sample driver
   - Devres:
       - Remove the inner reference count (Arc) and use pin-init instead
       - Replace Devres::new_foreign_owned() with devres::register()
       - Require T to be Send in Devres<T>
       - Initialize the data kept inside a Devres last
       - Provide an accessor for the Devres associated Device
   - Device ID:
       - Add support for ACPI device IDs and driver match tables
       - Split up generic device ID infrastructure
       - Use generic device ID infrastructure in net::phy
   - DMA:
       - Implement the dma::Device trait
       - Add DMA mask accessors to dma::Device
       - Implement dma::Device for PCI and platform devices
       - Use DMA masks from the DMA sample module
   - I/O:
       - Implement abstraction for resource regions (struct resource)
       - Implement resource-based ioremap() abstractions
       - Provide platform device accessors for I/O (remap) requests
   - Misc:
       - Support fallible PinInit types in Revocable
       - Implement Wrapper<T> for Opaque<T>
       - Merge pin-init blanket dependencies (for Devres)

  Misc:
   - Fix OF node leak in auxiliary_device_create()
   - Use util macros in device property iterators
   - Improve kobject sample code
   - Add device_link_test() for testing device link flags
   - Fix typo in Documentation/ABI/testing/sysfs-kernel-address_bits
   - Hint to prefer container_of_const() over container_of()"

* tag 'driver-core-6.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/driver-core/driver-core: (84 commits)
  rust: io: fix broken intra-doc links to `platform::Device`
  rust: io: fix broken intra-doc link to missing `flags` module
  rust: io: mem: enable IoRequest doc-tests
  rust: platform: add resource accessors
  rust: io: mem: add a generic iomem abstraction
  rust: io: add resource abstraction
  rust: samples: dma: set DMA mask
  rust: platform: implement the `dma::Device` trait
  rust: pci: implement the `dma::Device` trait
  rust: dma: add DMA addressing capabilities
  rust: dma: implement `dma::Device` trait
  rust: net::phy Change module_phy_driver macro to use module_device_table macro
  rust: net::phy represent DeviceId as transparent wrapper over mdio_device_id
  rust: device_id: split out index support into a separate trait
  device: rust: rename Device::as_ref() to Device::from_raw()
  arm64: cacheinfo: Provide helper to compress MPIDR value into u32
  cacheinfo: Add arch hook to compress CPU h/w id into 32 bits for cache-id
  cacheinfo: Set cache 'id' based on DT data
  container_of: Document container_of() is not to be used in new code
  driver core: auxiliary bus: fix OF node leak
  ...

It has turned out get_dev_from_fwnode() is useful at a few other places
outside of the driver core, as in gpiolib.c for example. Therefore let's
make it available as a common helper function.

Suggested-by: Saravana Kannan <saravanak@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tested-by: Hiago De Franco <hiago.franco@toradex.com> # Colibri iMX8X
Tested-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> # TI AM62A,Xilinx ZynqMP ZCU106
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20250701114733.636510-18-ulf.hansson@linaro.org