In the Linux kernel, the following vulnerability has been resolved:
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/[email protected]/
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/[email protected]/
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Workaround
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References
History
Sat, 15 Aug 2026 07:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-362 |
Sat, 15 Aug 2026 06:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: 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/[email protected]/ | |
| Title | usb: atm: ueagle-atm: wait for pre-firmware load in .disconnect() | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-08-15T05:51:17.487Z
Reserved: 2026-07-30T09:28:09.395Z
Link: CVE-2026-68456
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-08-15T06:17:32.713
Modified: 2026-08-15T06:17:32.713
Link: CVE-2026-68456
Redhat
No data.
OpenCVE Enrichment
Updated: 2026-08-15T07:30:05Z
Weaknesses