kernel/linux.git/drivers/power/sequencing, branch v7.2-rc1

power: sequencing: fix ABBA deadlock in pwrseq_device_unregister()

2026-06-22T08:05:39+00:00

The pwrseq core takes three locks in consistent order everywhere: pwrseq_sem -> pwrseq->rw_lock -> pwrseq->state_lock pwrseq_get() -> pwrseq_match_device() takes pwrseq_sem for reading, then rw_lock for reading. pwrseq_power_on()/pwrseq_power_off() take rw_lock for reading and then state_lock. pwrseq_device_unregister() is the only exception, it takes: state_lock, then rw_lock for writing and finally pwrseq_sem for writing. This created two potential ABBA deadlock situations that sashiko pointed out. - pwrseq_power_on/off() take rw_lock for reading then state_lock, while pwrseq_unregister() takes state_lock then rw_lock for writing - pwrseq_get() takes pwrseq_sem for reading then rw_lock for reading, while pwrseq_unregister() takes rw_lock for writing then pwrseq_sem for writing Reorder the unregister path to taking pwrseq_sem for writing -> rw_lock for writing and drop the state_lock entirely. This is safe as enable_count is only ever written under rw_lock held for read (via pwrseq_unit_enable()/disable(), reached only from pwrseq_power_on/off()), so holding rw_lock for writing already excludes every other writer and reader and the active-users WARN() stays race-free without state_lock. Fixes: 249ebf3f65f8 ("power: sequencing: implement the pwrseq core") Closes: https://sashiko.dev/#/patchset/20260616151049.1705503-1-vulab%40iscas.ac.cn Link: https://patch.msgid.link/20260618-pwrseq-abba-deadlock-v1-1-943a3fd81c06@oss.qualcomm.com Signed-off-by: Bartosz Golaszewski

power: sequencing: pcie-m2: Sort PCI device IDs in ascending order

2026-06-22T08:05:15+00:00

Sort the entries in pwrseq_m2_pci_ids[] by device ID in ascending order: 0x1103 (WCN6855) before 0x1107 (WCN7850). Fixes: 2abcfdd91e6a ("power: sequencing: pcie-m2: Add PCI ID 0x1103 for WCN6855 Bluetooth") Reviewed-by: Manivannan Sadhasivam Signed-off-by: Wei Deng Link: https://patch.msgid.link/20260617143055.820096-1-wei.deng@oss.qualcomm.com Signed-off-by: Bartosz Golaszewski

pwrseq: core: fix use-after-free in pwrseq_debugfs_seq_next()

2026-06-22T08:01:08+00:00

pwrseq_debugfs_seq_next() declares 'next' with __free(put_device), which causes put_device() to be called on the returned pointer when the variable goes out of scope. This results in a use-after-free since the seq_file framework receives a pointer whose reference has already been dropped. Simply removing __free(put_device) would fix the UAF but would leak the reference acquired by bus_find_next_device(), as stop() only calls up_read(&pwrseq_sem) and never releases the device reference. Fix this by making the reference counting consistent across all seq_file callbacks, matching the standard pattern used by PCI and SCSI: - start(): use get_device() so it returns a referenced pointer. - next(): explicitly put_device(curr) to release the previous device's reference (no NULL check needed - the seq_file framework only calls next() while the previous return was non-NULL). - stop(): put_device(data) to release the last iterated device's reference, with a NULL guard since stop() may be called with NULL when start() returned NULL or next() reached end-of-sequence. Cc: stable@vger.kernel.org Fixes: 249ebf3f65f8 ("power: sequencing: implement the pwrseq core") Signed-off-by: Wentao Liang Link: https://patch.msgid.link/20260616151049.1705503-1-vulab@iscas.ac.cn Signed-off-by: Bartosz Golaszewski

power: sequencing: pcie-m2: Add PCI ID 0x1103 for WCN6855 Bluetooth

2026-06-08T14:39:43+00:00

WCN6855 is a Qualcomm Wi-Fi/BT combo chip that uses PCI device ID 0x1103. Add it to pwrseq_m2_pci_ids[] alongside the existing 0x1107 (WCN7850) entry, so that the pwrseq-pcie-m2 driver creates a Bluetooth serdev device for WCN6855 cards inserted into PCIe M.2 Key E connectors. Reviewed-by: Manivannan Sadhasivam Signed-off-by: Wei Deng Link: https://patch.msgid.link/20260608091702.3797437-2-wei.deng@oss.qualcomm.com Signed-off-by: Bartosz Golaszewski

power: sequencing: Add an API to return the pwrseq device's 'dev' pointer

2026-06-08T08:03:43+00:00

The consumer drivers can make use of the pwrseq device's 'dev' pointer to query the pwrseq provider's DT node to check for existence of specific properties. Hence, add an API to return the pwrseq device's 'dev' pointer to consumers. Note that since pwrseq_get() would've increased the pwrseq refcount, there is no need to increase the refcount in this API again. Tested-by: Wei Deng Signed-off-by: Manivannan Sadhasivam Link: https://patch.msgid.link/20260519-pwrseq-m2-bt-v3-6-b39dc2ae3966@oss.qualcomm.com Signed-off-by: Bartosz Golaszewski

power: sequencing: pcie-m2: Create BT node based on the pci_device_id[] table

2026-06-08T07:47:56+00:00

Currently, pwrseq_pcie_m2_create_bt_node() hardcodes the BT compatible for creating the devicetree node. But to allow adding support for more devices in the future, create the BT node based on the pci_device_id[] table. The BT compatible is passed using 'driver_data'. Co-developed-by: Wei Deng Signed-off-by: Wei Deng Tested-by: Wei Deng Signed-off-by: Manivannan Sadhasivam Link: https://patch.msgid.link/20260519-pwrseq-m2-bt-v3-5-b39dc2ae3966@oss.qualcomm.com Signed-off-by: Bartosz Golaszewski

power: sequencing: pcie-m2: Create serdev for PCI devices present before probe

2026-06-08T07:47:56+00:00

So far, the driver is registering a notifier to create serdev for the PCI devices that are going to be attached after probe. But it doesn't handle the devices present before probe. Due to this, serdev is not getting created for those existing devices. Hence, create serdev for PCI devices available before probe as well. Note that the serdev for available devices are created before registering the notifier. There is a small window where a device could appear after pwrseq_pcie_m2_create_serdev(), before notifier registration. But since M.2 cards are fixed to a slot, they are mostly added either before booting the host or after using hotplug. So this window is mostly theoretical. Tested-by: Wei Deng Signed-off-by: Manivannan Sadhasivam Link: https://patch.msgid.link/20260519-pwrseq-m2-bt-v3-4-b39dc2ae3966@oss.qualcomm.com Signed-off-by: Bartosz Golaszewski

power: sequencing: pcie-m2: Improve PCI device ID check

2026-06-08T07:47:55+00:00

Instead of hardcoding the PCI device check, use pci_match_id() to check for the known IDs using the pwrseq_m2_pci_ids[] array. This makes adding support for new devices easier. Tested-by: Wei Deng Reviewed-by: Konrad Dybcio Signed-off-by: Manivannan Sadhasivam Link: https://patch.msgid.link/20260519-pwrseq-m2-bt-v3-3-b39dc2ae3966@oss.qualcomm.com Signed-off-by: Bartosz Golaszewski

power: sequencing: pcie-m2: Allow creating serdev for multiple PCI devices

2026-06-08T07:47:55+00:00

Current code makes it possible to create serdev for only one PCI device. But for scaling this driver, it is necessary to allow creating serdev for multiple PCI devices. Hence, add provision for it by creating 'struct pwrseq_pci_dev' for each PCI device that requires serdev and add them to 'pwrseq_pcie_m2_ctx::pci_devices' list. Tested-by: Wei Deng Signed-off-by: Manivannan Sadhasivam Link: https://patch.msgid.link/20260519-pwrseq-m2-bt-v3-2-b39dc2ae3966@oss.qualcomm.com Signed-off-by: Bartosz Golaszewski

power: sequencing: pcie-m2: Fix inconsistent function prefixes

2026-06-08T07:47:55+00:00

All functions in this driver follow 'pwrseq_pcie_m2' prefix except a few. Fix them to avoid inconsistency. Tested-by: Wei Deng Signed-off-by: Manivannan Sadhasivam Link: https://patch.msgid.link/20260519-pwrseq-m2-bt-v3-1-b39dc2ae3966@oss.qualcomm.com Signed-off-by: Bartosz Golaszewski