---
id: CVE-2022-50045
title: 'powerpc/pci: Fix get_phb_number() locking'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  powerpc/pci: Fix get_phb_number() locking

  The recent change to get_phb_number() causes a DEBUG_ATOMIC_SLEEP
  warning on some systems:

    BUG: sleeping function called f…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= a79e4395619c926ea7e828b2023c0fbe2776385b <
    6f75057c21eab12c6ccb7f06f859641a6edfab99
  - >-
    Linux >= 205826dcac3271ab04fb97d66f1b4f8219723259 <
    5db5ce0f1963c6c8275719a80cb65e9c98d32726
  - >-
    Linux >= 3ec50b8a0128359ff4ad4061a75c3322d0ab6ac9 <
    ccb0a42d3f40c436295e0fef57ab613ae5b925a4
  - >-
    Linux >= 47a8fe1b154aa6d836582365b1c70684af8597e4 <
    a868f771ee41c97a25a04b8c632a7f06689b307b
  - >-
    Linux >= ef0f4eeaba2463a77ac5a4e42c30717deb3c7b62 <
    1d9e75c3d8cdf7c96a94cb77450d4ee070279e6a
  - >-
    Linux >= f35c7f506fb96a23a1961c7314c5931ec8bc473e <
    90f195c01a2e8d8da6281791617e21109719c981
  - >-
    Linux >= 0fe1e96fef0a5c53b4c0d1500d356f3906000f81 <
    8d48562a2729742f767b0fdd994d6b2a56a49c63
  - Linux e0274da3ac318296fed503422ccda98ce67e99cb
  - Linux >= 5.18.18 < 5.19
  - Linux >= 5.10.137 < 5.10.138
  - Linux >= 5.15.61 < 5.15.63
  - Linux >= 5.19.2 < 5.19.4
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-05T19:53:24.838996Z'
published: '2025-06-18'
updated: '2026-11-05'
sourceUpdated: '2026-11-05T20:00:14.866Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2022-50045'
references:
  - url: 'https://git.kernel.org/stable/c/6f75057c21eab12c6ccb7f06f859641a6edfab99'
  - url: 'https://git.kernel.org/stable/c/5db5ce0f1963c6c8275719a80cb65e9c98d32726'
  - url: 'https://git.kernel.org/stable/c/ccb0a42d3f40c436295e0fef57ab613ae5b925a4'
  - url: 'https://git.kernel.org/stable/c/a868f771ee41c97a25a04b8c632a7f06689b307b'
  - url: 'https://git.kernel.org/stable/c/1d9e75c3d8cdf7c96a94cb77450d4ee070279e6a'
  - url: 'https://git.kernel.org/stable/c/90f195c01a2e8d8da6281791617e21109719c981'
  - url: 'https://git.kernel.org/stable/c/8d48562a2729742f767b0fdd994d6b2a56a49c63'
tags:
  - cve.org
epss: 0.00147
epssPercentile: 0.03945
ingestedAt: '2026-11-05T22:38:31.639Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

powerpc/pci: Fix get_phb_number() locking

The recent change to get_phb_number() causes a DEBUG_ATOMIC_SLEEP
warning on some systems:

  BUG: sleeping function called from invalid context at kernel/locking/mutex.c:580
  in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1, name: swapper
  preempt_count: 1, expected: 0
  RCU nest depth: 0, expected: 0
  1 lock held by swapper/1:
   #0: c157efb0 (hose_spinlock){+.+.}-{2:2}, at: pcibios_alloc_controller+0x64/0x220
  Preemption disabled at:
  [<00000000>] 0x0
  CPU: 0 PID: 1 Comm: swapper Not tainted 5.19.0-yocto-standard+ #1
  Call Trace:
  [d101dc90] [c073b264] dump_stack_lvl+0x50/0x8c (unreliable)
  [d101dcb0] [c0093b70] __might_resched+0x258/0x2a8
  [d101dcd0] [c0d3e634] __mutex_lock+0x6c/0x6ec
  [d101dd50] [c0a84174] of_alias_get_id+0x50/0xf4
  [d101dd80] [c002ec78] pcibios_alloc_controller+0x1b8/0x220
  [d101ddd0] [c140c9dc] pmac_pci_init+0x198/0x784
  [d101de50] [c140852c] discover_phbs+0x30/0x4c
  [d101de60] [c0007fd4] do_one_initcall+0x94/0x344
  [d101ded0] [c1403b40] kernel_init_freeable+0x1a8/0x22c
  [d101df10] [c00086e0] kernel_init+0x34/0x160
  [d101df30] [c001b334] ret_from_kernel_thread+0x5c/0x64

This is because pcibios_alloc_controller() holds hose_spinlock but
of_alias_get_id() takes of_mutex which can sleep.

The hose_spinlock protects the phb_bitmap, and also the hose_list, but
it doesn't need to be held while get_phb_number() calls the OF routines,
because those are only looking up information in the device tree.

So fix it by having get_phb_number() take the hose_spinlock itself, only
where required, and then dropping the lock before returning.
pcibios_alloc_controller() then needs to take the lock again before the
list_add() but that's safe, the order of the list is not important.

## Affected

- `Linux >= a79e4395619c926ea7e828b2023c0fbe2776385b < 6f75057c21eab12c6ccb7f06f859641a6edfab99`
- `Linux >= 205826dcac3271ab04fb97d66f1b4f8219723259 < 5db5ce0f1963c6c8275719a80cb65e9c98d32726`
- `Linux >= 3ec50b8a0128359ff4ad4061a75c3322d0ab6ac9 < ccb0a42d3f40c436295e0fef57ab613ae5b925a4`
- `Linux >= 47a8fe1b154aa6d836582365b1c70684af8597e4 < a868f771ee41c97a25a04b8c632a7f06689b307b`
- `Linux >= ef0f4eeaba2463a77ac5a4e42c30717deb3c7b62 < 1d9e75c3d8cdf7c96a94cb77450d4ee070279e6a`
- `Linux >= f35c7f506fb96a23a1961c7314c5931ec8bc473e < 90f195c01a2e8d8da6281791617e21109719c981`
- `Linux >= 0fe1e96fef0a5c53b4c0d1500d356f3906000f81 < 8d48562a2729742f767b0fdd994d6b2a56a49c63`
- `Linux e0274da3ac318296fed503422ccda98ce67e99cb`
- `Linux >= 5.18.18 < 5.19`
- `Linux >= 5.10.137 < 5.10.138`
- `Linux >= 5.15.61 < 5.15.63`
- `Linux >= 5.19.2 < 5.19.4`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.