Mauricio Faria de Oliveira e2674dfbed usb: atm: ueagle-atm: wait for pre-firmware load in .disconnect()
ueagle-atm uses the asynchronous request_firmware_nowait() in .probe(),
but does not wait for its completion, not even in .disconnect(); so, if the
device is unplugged meanwhile, its teardown runs concurrently with that.

Even though this inconsistency is worth addressing on its own, it has also
triggered several bug reports in syzbot over the years (some auto-closed)
where the firmware sysfs fallback mechanism (CONFIG_FW_LOADER_USER_HELPER)
creates a firmware subdirectory in the device directory during its removal,
which might hit unexpected conditions in kernfs, apparently, depending at
which point the add and remove operations raced. (See links.)

The pattern is:

usb ?-?: Direct firmware load for ueagle-atm/eagle?.fw failed with error -2
usb ?-?: Falling back to sysfs fallback for: ueagle-atm/eagle?.fw
<ERROR>
Call trace:
 ...
 kernfs_create_dir_ns
 sysfs_create_dir_ns
 create_dir
 kobject_add_internal
 kobject_add_varg
 kobject_add
 class_dir_create_and_add
 get_device_parent
 device_add
 fw_load_sysfs_fallback
 fw_load_from_user_helper
 firmware_fallback_sysfs
 _request_firmware
 request_firmware_work_func
 ...

(Some variations are observed, after fw_load_sysfs_fallback(), e.g., [1].)

While the kernfs side is being looked at, the ueagle-atm side can be fixed
by waiting for the pre-firmware load in the .disconnect() handler.

This change has a similar approach to previous work by Andrey Tsygunka [2]
(wait_for_completion() in .disconnect()), but it is relatively different in
design/implementation; using the Originally-by tag for credit assignment.

This has been tested with:
- synthetic reproducer to check the error path;
- USB gadget (virtual device) to check the firmware upload path;
- QEMU device emulator to check the device ID re-enumeration path;
(The latter two were written by Claude; no other code/text in this commit.)

Links (year first reported):
 2025 https://syzbot.org/bug?extid=ce1e5a1b4e086b43e56d
 2025 https://syzbot.org/bug?extid=9af8471255ac36e34fd4
 2024 https://syzbot.org/bug?extid=306212936b13e520679d
 2023 https://syzkaller.appspot.com/bug?extid=457452d30bcdda75ead2
 2022 https://syzbot.org/bug?extid=782984d6f1701b526edb
 2021 https://syzbot.org/bug?id=f3f221579f4ef7e9691281f3c6f56c05f83e8490
 2021 https://syzbot.org/bug?id=84d86f0d71394829df6fc53daf6642c045983881
 2021 https://syzbot.org/bug?id=3302dc1c0e2b9c94f2e8edb404eabc9267bc6f90

[1] https://syzkaller.appspot.com/bug?extid=457452d30bcdda75ead2
[2] https://lore.kernel.org/lkml/20250410093146.3776801-2-aitsygunka@yandex.ru/

Cc: stable <stable@kernel.org>
Reported-by: syzbot+ce1e5a1b4e086b43e56d@syzkaller.appspotmail.com
Closes: https://syzbot.org/bug?extid=ce1e5a1b4e086b43e56d
Reported-by: syzbot+306212936b13e520679d@syzkaller.appspotmail.com
Closes: https://syzbot.org/bug?extid=306212936b13e520679d
Reported-by: syzbot+457452d30bcdda75ead2@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=457452d30bcdda75ead2
Originally-by: Andrey Tsygunka <aitsygunka@yandex.ru>
Fixes: b72458a80c ("[PATCH] USB: Eagle and ADI 930 usb adsl modem driver")
Assisted-by: Claude:claude-opus-4.7 # usb gadget & qemu device for testing
Signed-off-by: Mauricio Faria de Oliveira <mfo@igalia.com>
Acked-by: Stanislaw Gruszka <stf_xl@wp.pl>
Link: https://patch.msgid.link/20260526-ueagle-atm_req-fw-sync-v3-1-93c01961daaf@igalia.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-06-25 16:03:39 +01:00
2026-01-26 19:07:09 -08:00
2022-09-28 09:02:20 +02:00
2025-02-19 14:53:27 -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
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