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Tycho Andersen (AMD) 0db3a430d9 iommu/amd: Fix IRQ unsafe locking in gdom allocation
Lockdep complains:

  [  259.410489] =====================================================
  [  259.417287] WARNING: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected
  [  259.424667] 7.0.0-g51db1d8d2113 #54 Not tainted
  [  259.429718] -----------------------------------------------------
  [  259.436516] qemu-system-x86/10143 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
  [  259.444670] ff3b2b1c60305170 (&xa->xa_lock#25){+.+.}-{3:3}, at: __domain_flush_pages+0x17c/0x4b0
  [  259.454485]
                 and this task is already holding:
  [  259.460991] ff3b2b1c98504cc0 (&domain->lock){-.-.}-{3:3}, at: amd_iommu_iotlb_sync+0x25/0x60
  [  259.470408] which would create a new lock dependency:
  [  259.476041]  (&domain->lock){-.-.}-{3:3} -> (&xa->xa_lock#25){+.+.}-{3:3}
  [  259.483615]
                 but this new dependency connects a HARDIRQ-irq-safe lock:
  [  259.492447]  (&domain->lock){-.-.}-{3:3}
  [  259.492449]
                 ... which became HARDIRQ-irq-safe at:
  [  259.503705]   lock_acquire+0xb6/0x2e0
  [  259.507790]   _raw_spin_lock_irqsave+0x3e/0x60
  [  259.512748]   amd_iommu_flush_iotlb_all+0x20/0x50
  [  259.517996]   iommu_dma_free_iova.isra.0+0x1b8/0x1e0
  [  259.523534]   __iommu_dma_unmap+0xc2/0x140
  [  259.528100]   iommu_dma_unmap_phys+0x55/0xc0
  [  259.532863]   dma_unmap_phys+0x274/0x2e0
  [  259.537238]   dma_unmap_page_attrs+0x17/0x30
  [  259.542000]   nvme_unmap_data+0x13e/0x280
  [  259.546473]   nvme_pci_complete_batch+0x45/0x70
  [  259.551524]   nvme_irq+0x83/0x90
  [  259.555123]   __handle_irq_event_percpu+0x92/0x360
  [  259.560466]   handle_irq_event+0x39/0x80
  [  259.564841]   handle_edge_irq+0xb2/0x1a0
  [  259.569214]   __common_interrupt+0x4e/0x130
  [  259.573882]   common_interrupt+0x88/0xa0
  [  259.578256]   asm_common_interrupt+0x27/0x40
  [  259.583019]   cpuidle_enter_state+0x119/0x5d0
  [  259.587877]   cpuidle_enter+0x2e/0x50
  [  259.591962]   do_idle+0x153/0x2c0
  [  259.595657]   cpu_startup_entry+0x29/0x30
  [  259.600128]   start_secondary+0x118/0x150
  [  259.604601]   common_startup_64+0x13e/0x141
  [  259.609266]
                 to a HARDIRQ-irq-unsafe lock:
  [  259.615384]  (&xa->xa_lock#25){+.+.}-{3:3}
  [  259.615386]
                 ... which became HARDIRQ-irq-unsafe at:
  [  259.627039] ...
  [  259.627039]   lock_acquire+0xb6/0x2e0
  [  259.633071]   _raw_spin_lock+0x2f/0x50
  [  259.637250]   amd_iommu_alloc_domain_nested+0x140/0x3c0
  [  259.643078]   iommufd_hwpt_alloc+0x272/0x800 [iommufd]
  [  259.648813]   iommufd_fops_ioctl+0x14e/0x200 [iommufd]
  [  259.654547]   __x64_sys_ioctl+0x9d/0xf0
  ...

Since amd_iommu_domain_flush_pages() necessarily holds domain->lock to do the
flush, switch the allocation side in gdom_info_load_or_alloc_locked() to
HARDIRQ-safe allocation. The IOMMU_DESTROY->free path has the same issue,
so switch that path to HARDIRQ-safe locking as well.

Fixes: 757d2b1fdf ("iommu/amd: Introduce gDomID-to-hDomID Mapping and handle parent domain invalidation")
Signed-off-by: Tycho Andersen (AMD) <tycho@kernel.org>
Reviewed-by: Ankit Soni <Ankit.Soni@amd.com>
Signed-off-by: Will Deacon <will@kernel.org>
2026-07-15 12:28:04 +01:00
arch - Prevent OOB access in the resctrl code while offlining 2026-07-05 05:37:46 -10:00
block block: handle REQ_OP_ZONE_APPEND in __bio_integrity_action 2026-06-24 06:53:25 -06:00
certs treewide: fix indentation and whitespace in Kconfig files 2026-05-28 21:24:42 -07:00
crypto mm.git review status for mm-hotfixes-stable..mm-nonmm-stable 2026-06-21 13:20:19 -07:00
Documentation sound fixes for 7.2-rc2 2026-07-05 05:26:45 -10:00
drivers iommu/amd: Fix IRQ unsafe locking in gdom allocation 2026-07-15 12:28:04 +01:00
fs - Prevent OOB access in the resctrl code while offlining 2026-07-05 05:37:46 -10:00
include drm fixes for 7.2-rc2 2026-07-03 15:42:20 -10:00
init mm.git review status for mm-hotfixes-stable..mm-nonmm-stable 2026-06-21 13:20:19 -07:00
io_uring io_uring-7.2-20260625 2026-06-25 09:53:31 -07:00
ipc kernel-7.2-rc1.misc 2026-06-15 03:05:50 +05:30
kernel Misc perf events fixes: 2026-07-05 05:34:43 -10:00
lib RISC-V updates for v7.2-rc2 2026-07-03 15:07:24 -10:00
LICENSES LICENSES: Add modern form of the LGPL-2.1 tags to the usage guide section 2025-10-22 07:58:19 +02:00
mm block-7.2-20260625 2026-06-25 09:56:47 -07:00
net Split <linux/mod_devicetable.h> in per subsystem headers 2026-07-02 20:54:26 -10:00
rust Rust changes for v7.2 (addendum) 2026-06-24 15:11:08 -07:00
samples tracing/events: Fix to check the simple_tsk_fn creation 2026-06-30 23:58:19 +09:00
scripts scripts/sorttable: Handle RISC-V patchable ftrace entries 2026-06-25 13:15:03 -06:00
security bpf: Reject BPF_MAP_TYPE_INODE_STORAGE creation if BPF LSM is uninitialized 2026-06-30 16:31:56 +02:00
sound sound fixes for 7.2-rc2 2026-07-05 05:26:45 -10:00
tools Misc perf events fixes: 2026-07-05 05:34:43 -10:00
usr kbuild: uapi: also test UAPI headers against C++ compilers 2026-03-25 13:24:42 +01:00
virt s390: 2026-06-25 10:21:13 -07:00
.clang-format clang-format: fix formatting of guard() and scoped_guard() statements 2026-05-28 21:24:41 -07:00
.clippy.toml rust: bump Clippy's MSRV and clean incompatible_msrv allows 2026-04-07 09:51:39 +02:00
.cocciconfig
.editorconfig editorconfig: add rst extension 2026-01-26 19:07:09 -08:00
.get_maintainer.ignore .get_maintainer.ignore: add myself 2026-04-02 16:48:25 +02:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore SPDX patches for 7.2-rc1 2026-06-22 12:06:22 -07:00
.mailmap MAINTAINERS: Update Jason Wang's email address 2026-06-29 19:09:00 -07:00
.pylintrc docs: Move the python libraries to tools/lib/python 2025-11-18 09:22:40 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING
CREDITS mm.git review status for mm-hotfixes-stable..mm-nonmm-stable 2026-06-21 13:20:19 -07:00
Kbuild checksyscalls: move instance functionality into generic code 2026-04-05 09:21:32 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS sound fixes for 7.2-rc2 2026-07-05 05:26:45 -10:00
Makefile Linux 7.2-rc2 2026-07-05 14:44:06 -10:00
README docs: add AI Coding Assistants documentation 2026-01-06 14:55:06 -07:00

Linux kernel
============

The Linux kernel is the core of any Linux operating system. It manages hardware,
system resources, and provides the fundamental services for all other software.

Quick Start
-----------

* Report a bug: See Documentation/admin-guide/reporting-issues.rst
* Get the latest kernel: https://kernel.org
* Build the kernel: See Documentation/admin-guide/quickly-build-trimmed-linux.rst
* Join the community: https://lore.kernel.org/

Essential Documentation
-----------------------

All users should be familiar with:

* Building requirements: Documentation/process/changes.rst
* Code of Conduct: Documentation/process/code-of-conduct.rst
* License: See COPYING

Documentation can be built with make htmldocs or viewed online at:
https://www.kernel.org/doc/html/latest/


Who Are You?
============

Find your role below:

* New Kernel Developer - Getting started with kernel development
* Academic Researcher - Studying kernel internals and architecture
* Security Expert - Hardening and vulnerability analysis
* Backport/Maintenance Engineer - Maintaining stable kernels
* System Administrator - Configuring and troubleshooting
* Maintainer - Leading subsystems and reviewing patches
* Hardware Vendor - Writing drivers for new hardware
* Distribution Maintainer - Packaging kernels for distros
* AI Coding Assistant - LLMs and AI-powered development tools


For Specific Users
==================

New Kernel Developer
--------------------

Welcome! Start your kernel development journey here:

* Getting Started: Documentation/process/development-process.rst
* Your First Patch: Documentation/process/submitting-patches.rst
* Coding Style: Documentation/process/coding-style.rst
* Build System: Documentation/kbuild/index.rst
* Development Tools: Documentation/dev-tools/index.rst
* Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst
* Core APIs: Documentation/core-api/index.rst

Academic Researcher
-------------------

Explore the kernel's architecture and internals:

* Researcher Guidelines: Documentation/process/researcher-guidelines.rst
* Memory Management: Documentation/mm/index.rst
* Scheduler: Documentation/scheduler/index.rst
* Networking Stack: Documentation/networking/index.rst
* Filesystems: Documentation/filesystems/index.rst
* RCU (Read-Copy Update): Documentation/RCU/index.rst
* Locking Primitives: Documentation/locking/index.rst
* Power Management: Documentation/power/index.rst

Security Expert
---------------

Security documentation and hardening guides:

* Security Documentation: Documentation/security/index.rst
* LSM Development: Documentation/security/lsm-development.rst
* Self Protection: Documentation/security/self-protection.rst
* Reporting Vulnerabilities: Documentation/process/security-bugs.rst
* CVE Procedures: Documentation/process/cve.rst
* Embargoed Hardware Issues: Documentation/process/embargoed-hardware-issues.rst
* Security Features: Documentation/userspace-api/seccomp_filter.rst

Backport/Maintenance Engineer
-----------------------------

Maintain and stabilize kernel versions:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* Backporting Guide: Documentation/process/backporting.rst
* Applying Patches: Documentation/process/applying-patches.rst
* Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git for Maintainers: Documentation/maintainer/configure-git.rst

System Administrator
--------------------

Configure, tune, and troubleshoot Linux systems:

* Admin Guide: Documentation/admin-guide/index.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst
* Tracing/Debugging: Documentation/trace/index.rst
* Performance Security: Documentation/admin-guide/perf-security.rst
* Hardware Monitoring: Documentation/hwmon/index.rst

Maintainer
----------

Lead kernel subsystems and manage contributions:

* Maintainer Handbook: Documentation/maintainer/index.rst
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* Git Configuration: Documentation/maintainer/configure-git.rst

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---------------

Write drivers and support new hardware:

* Driver API Guide: Documentation/driver-api/index.rst
* Driver Model: Documentation/driver-api/driver-model/driver.rst
* Device Drivers: Documentation/driver-api/infrastructure.rst
* Bus Types: Documentation/driver-api/driver-model/bus.rst
* Device Tree Bindings: Documentation/devicetree/bindings/
* Power Management: Documentation/driver-api/pm/index.rst
* DMA API: Documentation/core-api/dma-api.rst

Distribution Maintainer
-----------------------

Package and distribute the kernel:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* ABI Documentation: Documentation/ABI/README
* Kernel Configuration: Documentation/kbuild/kconfig.rst
* Module Signing: Documentation/admin-guide/module-signing.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst

AI Coding Assistant
-------------------

CRITICAL: If you are an LLM or AI-powered coding assistant, you MUST read and
follow the AI coding assistants documentation before contributing to the Linux
kernel:

* Documentation/process/coding-assistants.rst

This documentation contains essential requirements about licensing, attribution,
and the Developer Certificate of Origin that all AI tools must comply with.


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=========================

* Mailing Lists: https://lore.kernel.org/
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