kernel/linux.git/drivers/base/power/runtime.c, branch v6.18.21

PM: runtime: Fix a race condition related to device removal

2026-03-25T10:10:41+00:00

[ Upstream commit 29ab768277617452d88c0607c9299cdc63b6e9ff ] The following code in pm_runtime_work() may dereference the dev->parent pointer after the parent device has been freed: /* Maybe the parent is now able to suspend. */ if (parent && !parent->power.ignore_children) { spin_unlock(&dev->power.lock); spin_lock(&parent->power.lock); rpm_idle(parent, RPM_ASYNC); spin_unlock(&parent->power.lock); spin_lock(&dev->power.lock); } Fix this by inserting a flush_work() call in pm_runtime_remove(). Without this patch blktest block/001 triggers the following complaint sporadically: BUG: KASAN: slab-use-after-free in lock_acquire+0x70/0x160 Read of size 1 at addr ffff88812bef7198 by task kworker/u553:1/3081 Workqueue: pm pm_runtime_work Call Trace: dump_stack_lvl+0x61/0x80 print_address_description.constprop.0+0x8b/0x310 print_report+0xfd/0x1d7 kasan_report+0xd8/0x1d0 __kasan_check_byte+0x42/0x60 lock_acquire.part.0+0x38/0x230 lock_acquire+0x70/0x160 _raw_spin_lock+0x36/0x50 rpm_suspend+0xc6a/0xfe0 rpm_idle+0x578/0x770 pm_runtime_work+0xee/0x120 process_one_work+0xde3/0x1410 worker_thread+0x5eb/0xfe0 kthread+0x37b/0x480 ret_from_fork+0x6cb/0x920 ret_from_fork_asm+0x11/0x20 Allocated by task 4314: kasan_save_stack+0x2a/0x50 kasan_save_track+0x18/0x40 kasan_save_alloc_info+0x3d/0x50 __kasan_kmalloc+0xa0/0xb0 __kmalloc_noprof+0x311/0x990 scsi_alloc_target+0x122/0xb60 [scsi_mod] __scsi_scan_target+0x101/0x460 [scsi_mod] scsi_scan_channel+0x179/0x1c0 [scsi_mod] scsi_scan_host_selected+0x259/0x2d0 [scsi_mod] store_scan+0x2d2/0x390 [scsi_mod] dev_attr_store+0x43/0x80 sysfs_kf_write+0xde/0x140 kernfs_fop_write_iter+0x3ef/0x670 vfs_write+0x506/0x1470 ksys_write+0xfd/0x230 __x64_sys_write+0x76/0xc0 x64_sys_call+0x213/0x1810 do_syscall_64+0xee/0xfc0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 Freed by task 4314: kasan_save_stack+0x2a/0x50 kasan_save_track+0x18/0x40 kasan_save_free_info+0x3f/0x50 __kasan_slab_free+0x67/0x80 kfree+0x225/0x6c0 scsi_target_dev_release+0x3d/0x60 [scsi_mod] device_release+0xa3/0x220 kobject_cleanup+0x105/0x3a0 kobject_put+0x72/0xd0 put_device+0x17/0x20 scsi_device_dev_release+0xacf/0x12c0 [scsi_mod] device_release+0xa3/0x220 kobject_cleanup+0x105/0x3a0 kobject_put+0x72/0xd0 put_device+0x17/0x20 scsi_device_put+0x7f/0xc0 [scsi_mod] sdev_store_delete+0xa5/0x120 [scsi_mod] dev_attr_store+0x43/0x80 sysfs_kf_write+0xde/0x140 kernfs_fop_write_iter+0x3ef/0x670 vfs_write+0x506/0x1470 ksys_write+0xfd/0x230 __x64_sys_write+0x76/0xc0 x64_sys_call+0x213/0x1810 Reported-by: Ming Lei Closes: https://lore.kernel.org/all/ZxdNvLNI8QaOfD2d@fedora/ Reported-by: syzbot+6c905ab800f20cf4086c@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/68c13942.050a0220.2ff435.000b.GAE@google.com/ Fixes: 5e928f77a09a ("PM: Introduce core framework for run-time PM of I/O devices (rev. 17)") Signed-off-by: Bart Van Assche Link: https://patch.msgid.link/20260312182720.2776083-1-bvanassche@acm.org Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin

PM: runtime: Do not clear needs_force_resume with enabled runtime PM

2026-01-02T11:57:22+00:00

commit 359afc8eb02a518fbdd0cbd462c8c2827c6cbec2 upstream. Commit 89d9cec3b1e9 ("PM: runtime: Clear power.needs_force_resume in pm_runtime_reinit()") added provisional clearing of power.needs_force_resume to pm_runtime_reinit(), but it is done unconditionally which is a mistake because pm_runtime_reinit() may race with driver probing and removal [1]. To address this, notice that power.needs_force_resume should never be set when runtime PM is enabled and so it only needs to be cleared when runtime PM is disabled, and update pm_runtime_init() to only clear that flag when runtime PM is disabled. Fixes: 89d9cec3b1e9 ("PM: runtime: Clear power.needs_force_resume in pm_runtime_reinit()") Reported-by: Ed Tsai Closes: https://lore.kernel.org/linux-pm/20251215122154.3180001-1-ed.tsai@mediatek.com/ [1] Signed-off-by: Rafael J. Wysocki Cc: 6.17+ # 6.17+ Reviewed-by: Ulf Hansson Link: https://patch.msgid.link/12807571.O9o76ZdvQC@rafael.j.wysocki Signed-off-by: Greg Kroah-Hartman

Merge branches 'pm-core' and 'pm-runtime'

2025-10-07T10:20:36+00:00

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

PM: runtime: Add auto-cleanup macros for "resume and get" operations

2025-09-29T15:00:21+00:00

It is generally useful to be able to automatically drop a device's runtime PM usage counter incremented by runtime PM operations that resume a device and bump up its usage counter [1]. To that end, add guard definition macros allowing pm_runtime_put() and pm_runtime_put_autosuspend() to be used for the auto-cleanup in those cases. Simply put, a piece of code like below: pm_runtime_get_sync(dev); ..... pm_runtime_put(dev); return 0; can be transformed with guard() like: guard(pm_runtime_active)(dev); ..... return 0; (see the pm_runtime_put() call is gone). However, it is better to do proper error handling in the majority of cases, so doing something like this instead of the above is recommended: ACQUIRE(pm_runtime_active_try, pm)(dev); if (ACQUIRE_ERR(pm_runtime_active_try, &pm)) return -ENXIO; ..... return 0; In all of the cases in which runtime PM is known to be enabled for the given device or the device can be regarded as operational (and so it can be accessed) with runtime PM disabled, a piece of code like: ret = pm_runtime_resume_and_get(dev); if (ret < 0) return ret; ..... pm_runtime_put(dev); return 0; can be changed as follows: ACQUIRE(pm_runtime_active_try, pm)(dev); ret = ACQUIRE_ERR(pm_runtime_active_try, &pm); if (ret < 0) return ret; ..... return 0; (again, see the pm_runtime_put() call is gone). Still, if the device cannot be accessed unless runtime PM has been enabled for it, the pm_runtime_active_try_enabled guard variant needs to be used, that is (in the context of the example above): ACQUIRE(pm_runtime_active_try_enabled, pm)(dev); ret = ACQUIRE_ERR(pm_runtime_active_try_enabled, &pm); if (ret < 0) return ret; ..... return 0; When the original code calls pm_runtime_put_autosuspend(), use one of the "auto" guard variants, pm_runtime_active_auto/_try/_enabled, so for example, a piece of code like: ret = pm_runtime_resume_and_get(dev); if (ret < 0) return ret; ..... pm_runtime_put_autosuspend(dev); return 0; will become: ACQUIRE(pm_runtime_active_auto_try_enabled, pm)(dev); ret = ACQUIRE_ERR(pm_runtime_active_auto_try_enabled, &pm); if (ret < 0) return ret; ..... return 0; Note that the cases in which the return value of pm_runtime_get_sync() is checked can also be handled with the help of the new guard macros. For example, a piece of code like: ret = pm_runtime_get_sync(dev); if (ret < 0) { pm_runtime_put(dev); return ret; } ..... pm_runtime_put(dev); return 0; can be rewritten as: ACQUIRE(pm_runtime_active_auto_try_enabled, pm)(dev); ret = ACQUIRE_ERR(pm_runtime_active_auto_try_enabled, &pm); if (ret < 0) return ret; ..... return 0; or pm_runtime_get_active_try can be used if transparent handling of disabled runtime PM is desirable. Link: https://lore.kernel.org/linux-pm/878qimv24u.wl-tiwai@suse.de/ [1] Link: https://lore.kernel.org/linux-pm/20250926150613.000073a4@huawei.com/ Signed-off-by: Rafael J. Wysocki Acked-by: Dan Williams Reviewed-by: Takashi Iwai Link: https://patch.msgid.link/2238241.irdbgypaU6@rafael.j.wysocki [ rjw: Fixed leftovers from the previous version in the changelog ] Reviewed-by: Jonathan Cameron Reviewed-by: Dhruva Gole Signed-off-by: Rafael J. Wysocki

PM: runtime: Make put{,_sync}() return 1 when already suspended

2025-09-27T11:41:47+00:00

The pm_runtime.h docs say pm_runtime_put() and pm_runtime_put_sync() return 1 when already suspended, but this is not true -- they return -EAGAIN. On the other hand, pm_runtime_put_sync_suspend() and pm_runtime_put_sync_autosuspend() *do* return 1. This is an artifact of the fact that the former are built on rpm_idle(), whereas the latter are built on rpm_suspend(). There are precious few pm_runtime_put()/pm_runtime_put_sync() callers that check the return code at all, but most of them only log errors, and usually only for negative error codes. None of them should be treating this as an error, so: * at best, this may fix some case where a driver treats this condition as an error, when it shouldn't; * at worst, this should make no effect; and * somewhere in between, we could potentially clear up non-fatal log messages. Fix the pm_runtime_already_suspended_test() while tweaking the behavior. The test makes a lot more sense when these all return 1 when the device is already suspended: pm_runtime_put_sync(dev); pm_runtime_suspend(dev); pm_runtime_autosuspend(dev); pm_request_autosuspend(dev); pm_runtime_put_sync_autosuspend(dev); Notably, I've avoided testing the return codes for these, since they really should be ignored by callers, and we may make them 'void' altogether: pm_runtime_put(dev); pm_runtime_put_autosuspend(dev); Signed-off-by: Brian Norris Reviewed-by: Dhruva Gole Reviewed-by: Sakari Ailus Signed-off-by: Rafael J. Wysocki

PM: core: Add two macros for walking device links

2025-09-06T15:16:32+00:00

Add separate macros for walking links to suppliers and consumers of a device to help device links users to avoid exposing the internals of struct dev_links_info in their code and possible coding mistakes related to that. Accordingly, use the new macros to replace open-coded device links list walks in the core power management code. No intentional functional impact. Signed-off-by: Rafael J. Wysocki Reviewed-by: Ulf Hansson Acked-by: Greg Kroah-Hartman Link: https://patch.msgid.link/1944671.tdWV9SEqCh@rafael.j.wysocki

PM: core: Annotate loops walking device links as _srcu

2025-09-06T15:16:06+00:00

Since SRCU is used for the protection of device link lists, the loops over device link lists in multiple places in drivers/base/power/main.c and in pm_runtime_get_suppliers() should be annotated as _srcu rather than as _rcu which is the case currently. Change the annotations accordingly. Signed-off-by: Rafael J. Wysocki Reviewed-by: Ulf Hansson Acked-by: Greg Kroah-Hartman Link: https://patch.msgid.link/2393512.ElGaqSPkdT@rafael.j.wysocki

Merge tag 'driver-core-6.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/driver-core/driver-core

2025-07-29T19:15:39+00:00

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 - 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 for Opaque - 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 ...

Merge branches 'pm-runtime' and 'pm-powercap'

2025-07-22T16:01:15+00:00

Merge runtime PM updates and power capping updates for 6.17-rc1: - Document return values of suspend-related API functions in the runtime PM framework (Sakari Ailus) - Mark last busy stamp in multiple autosuspend-related functions in the runtime PM framework and update its documentation (Sakari Ailus) - Take active children into account in pm_runtime_get_if_in_use() for consistency (Rafael Wysocki) - Fix NULL pointer dereference in get_pd_power_uw() in the dtpm_cpu power capping driver (Sivan Zohar-Kotzer) - Add support for the Bartlett Lake platform to the Intel RAPL power capping driver (Qiao Wei) - Add PL4 support for Panther Lake to the intel_rapl_msr power capping driver (Zhang Rui) * pm-runtime: PM: runtime: Take active children into account in pm_runtime_get_if_in_use() Documentation: PM: *_autosuspend() functions update last busy time PM: runtime: Mark last busy stamp in pm_request_autosuspend() PM: runtime: Mark last busy stamp in pm_runtime_autosuspend() PM: runtime: Mark last busy stamp in pm_runtime_put_sync_autosuspend() PM: runtime: Mark last busy stamp in pm_runtime_put_autosuspend() PM: runtime: Document return values of suspend-related API functions * pm-powercap: powercap: dtpm_cpu: Fix NULL pointer dereference in get_pd_power_uw() powercap: intel_rapl: Add support for Bartlett Lake platform powercap: intel_rapl_msr: Add PL4 support for Panther Lake

PM: runtime: Take active children into account in pm_runtime_get_if_in_use()

2025-07-15T13:03:25+00:00

For all practical purposes, there is no difference between the situation in which a given device is not ignoring children and its active child count is nonzero and the situation in which its runtime PM usage counter is nonzero. However, pm_runtime_get_if_in_use() will only increment the device's usage counter and return 1 in the latter case. For consistency, make it do so in the former case either by adjusting pm_runtime_get_conditional() and update the related kerneldoc comments accordingly. Fixes: c111566bea7c ("PM: runtime: Add pm_runtime_get_if_active()") Signed-off-by: Rafael J. Wysocki Reviewed-by: Ulf Hansson Reviewed-by: Sakari Ailus Cc: 5.10+ # 5.10+: c0ef3df8dbae: PM: runtime: Simplify pm_runtime_get_if_active() usage Cc: 5.10+ # 5.10+ Link: https://patch.msgid.link/12700973.O9o76ZdvQC@rjwysocki.net