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Cen Zhang f199c8a8bd ALSA: usb-audio: Kill MIDI 2.0 URBs before freeing endpoints
MIDI 2.0 input URBs are started during snd_usb_midi_v2_create(). A
later setup failure can still jump to snd_usb_midi_v2_free(), which
currently frees each endpoint and its coherent URB buffers without first
stopping the submitted URBs. A completion can then dereference the
embedded URB context and endpoint state after they have been freed, or
try to resubmit from the stale endpoint.

This was observed as a KASAN slab-use-after-free in
input_urb_complete().

The buggy scenario involves two paths, with each column showing the order
within that path:

probe error path:                         USB completion path:
1. start_input_streams() submits          1. The HCD still owns a
   input URBs.                               submitted input URB.
2. A later setup helper returns           2. input_urb_complete() runs
   an error.                                 with urb->context in ep.
3. snd_usb_midi_v2_free() frees           3. The completion reads ep
   endpoint storage and URB buffers.         state and can requeue URBs.

Make the endpoint destructor follow the same teardown ordering used for
disconnect when the endpoint has not already been disconnected: publish
ep->disconnected, kill the URBs synchronously, and drain the endpoint
before freeing URB buffers and endpoint storage. The guard avoids
repeating the stop sequence after the normal
snd_usb_midi_v2_disconnect_all() path, while still synchronizing the
direct MIDI 2.0 create-error free path.

Validation reproduced this kernel report:
BUG: KASAN: slab-use-after-free in input_urb_complete+0x37/0x1b0
Workqueue: usb_hub_wq hub_event
RIP: 0010:_raw_spin_unlock_irq+0x2e/0x50
Read of size 8
Call trace:
  dump_stack_lvl+0x77/0xb0
  print_report+0xce/0x5f0
  input_urb_complete+0x37/0x1b0 (sound/usb/midi2.c:186)
  srso_alias_return_thunk+0x5/0xfbef5
  __virt_addr_valid+0x19f/0x330
  kasan_report+0xe0/0x110
  __usb_hcd_giveback_urb+0x112/0x1d0
  dummy_timer+0xaaa/0x19a0
  lock_is_held_type+0x9a/0x110
  __lock_acquire+0x467/0x28b0
  mark_held_locks+0x40/0x70
  _raw_spin_unlock_irqrestore+0x44/0x60
  lockdep_hardirqs_on_prepare+0xbb/0x1a0
  __hrtimer_run_queues+0x101/0x520
  hrtimer_run_softirq+0xd0/0x130
  handle_softirqs+0x15b/0x670
  __irq_exit_rcu+0xd0/0x170
  irq_exit_rcu+0xe/0x20
  sysvec_apic_timer_interrupt+0x6c/0x80
  asm_sysvec_apic_timer_interrupt+0x1a/0x20

Fixes: d9c9987686 ("ALSA: usb-audio: Create UMP blocks from USB MIDI GTBs")
Assisted-by: Codex:gpt-5.5
Signed-off-by: Cen Zhang <zzzccc427@gmail.com>
Link: https://patch.msgid.link/20260618170010.191433-1-zzzccc427@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2026-06-19 10:49:21 +02:00
arch sh: roll back Ecovec24/7724se Sound support 2026-06-10 12:00:23 +01:00
block block-7.1-20260529 2026-05-29 10:41:07 -07:00
certs Clang build fixes for 7.1 2026-04-24 09:29:51 -07:00
crypto crypto/krb5, rxrpc: Fix lack of pre-decrypt/pre-verify length checks 2026-05-20 16:36:45 -07:00
Documentation ASoC: Updates for v7.2 2026-06-15 20:19:22 +02:00
drivers ASoC: Updates for v7.2 2026-06-15 20:19:22 +02:00
fs vfs-7.1-rc7.fixes 2026-06-06 07:28:59 -07:00
include ASoC: Updates for v7.2 2026-06-15 20:19:22 +02:00
init memblock: updates for 7.0-rc1 2026-04-18 11:29:14 -07:00
io_uring io_uring-7.1-20260605 2026-06-05 13:52:15 -07:00
ipc ipc: limit next_id allocation to the valid ID range 2026-05-21 19:06:11 -07:00
kernel Miscellaneous timer fixes: 2026-06-07 13:02:02 -07:00
lib vdso/datastore: Mark vdso_k_*_data pointers as __ro_after_init 2026-06-02 21:39:29 +02:00
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 13 hotfixes. All are for MM. 10 are cc:stable and the remaining 3 2026-06-02 08:59:35 -07:00
net udp: clear skb->dev before running a sockmap verdict 2026-06-04 09:01:51 -07:00
rust rust: helpers: add is_vmalloc_addr wrapper for NOMMU builds 2026-05-27 20:01:04 +02:00
samples soc: drivers for 7.1 2026-04-16 20:34:34 -07:00
scripts Rust fixes for v7.1 (2nd) 2026-06-06 09:44:42 -07:00
security security/keys: fix missed RCU read section on lookup 2026-05-28 11:45:41 -07:00
sound ALSA: usb-audio: Kill MIDI 2.0 URBs before freeing endpoints 2026-06-19 10:49:21 +02:00
tools vfs-7.1-rc7.fixes 2026-06-06 07:28:59 -07:00
usr kbuild: uapi: also test UAPI headers against C++ compilers 2026-03-25 13:24:42 +01:00
virt KVM: Don't WARN if memory is dirtied without a vCPU when the VM is dying 2026-06-03 16:43:55 +02:00
.clang-format Devicetree updates for v7.0: 2026-02-11 18:27:08 -08:00
.clippy.toml rust: bump Clippy's MSRV and clean incompatible_msrv allows 2026-04-07 09:51:39 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.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 kbuild: rust: provide an option to inline C helpers into Rust 2026-03-30 02:03:52 +02:00
.mailmap 13 hotfixes. 9 are for MM. 9 are cc:stable and the remaining 4 address 2026-05-26 08:23:19 -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 COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS Delete some obsolete networking code 2026-04-24 09:41:58 -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 ASoC: simple-card: remove platform data style 2026-06-08 18:55:01 +01:00
Makefile Linux 7.1-rc7 2026-06-07 15:37:58 -07:00
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
* Pull Requests: Documentation/maintainer/pull-requests.rst
* Managing Patches: Documentation/maintainer/modifying-patches.rst
* Rebasing and Merging: Documentation/maintainer/rebasing-and-merging.rst
* Development Process: Documentation/process/maintainer-handbooks.rst
* Maintainer Entry Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git Configuration: Documentation/maintainer/configure-git.rst

Hardware Vendor
---------------

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.


Communication and Support
=========================

* Mailing Lists: https://lore.kernel.org/
* IRC: #kernelnewbies on irc.oftc.net
* Bugzilla: https://bugzilla.kernel.org/
* MAINTAINERS file: Lists subsystem maintainers and mailing lists
* Email Clients: Documentation/process/email-clients.rst