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Mauricio Faria de OliveiraandGreg Kroah-Hartman
bbfedc8471
[ Upstream commite2674dfbed] 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> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.