In the Linux kernel, the following vulnerability has been resolved:
gpio: sloppy-logic-analyzer: fix use-after-free via debugfs trigger on unbind
The "trigger" debugfs file has a hand-rolled ->write handler
(trigger_write()) that dereferences the per-device gpio_la_poll_priv. The
file is created with debugfs_create_file_unsafe(), and the handler never
takes a debugfs reference. Nothing keeps the object alive while the
handler runs.
priv is allocated with devm_kzalloc(). devres frees it when the platform
device is unbound. debugfs_create_file_unsafe() installs no full_proxy
wrapper, so debugfs_remove_recursive() in gpio_la_poll_remove() does not
wait for an in-flight trigger_write(). The blob_lock taken there does not
help, because trigger_write() never takes it. A write that races an unbind
therefore writes into freed memory:
trigger_write() gpio_la_poll_remove()
priv = m->private
buf = memdup_user() [may sleep]
mutex_lock(&priv->blob_lock)
debugfs_remove_recursive() [no wait]
mutex_unlock(&priv->blob_lock)
(remove returns; devres frees priv)
priv->trig_data = buf <-- use-after-free write
priv->trig_len = count
The race is reachable by root via
/sys/bus/platform/drivers/gpio-sloppy-logic-analyzer/unbind.
Create "trigger" with debugfs_create_file() instead. Its full_proxy
wrapper makes debugfs_remove_recursive() drain any in-flight ->write
before it returns.
The use-after-free is confirmed under KASAN with a minimal reproducer of
the same debugfs_create_file_unsafe() plus devm_kzalloc() pattern
(available on request); it produces a slab-use-after-free write in the
handler.
gpio: sloppy-logic-analyzer: fix use-after-free via debugfs trigger on unbind
The "trigger" debugfs file has a hand-rolled ->write handler
(trigger_write()) that dereferences the per-device gpio_la_poll_priv. The
file is created with debugfs_create_file_unsafe(), and the handler never
takes a debugfs reference. Nothing keeps the object alive while the
handler runs.
priv is allocated with devm_kzalloc(). devres frees it when the platform
device is unbound. debugfs_create_file_unsafe() installs no full_proxy
wrapper, so debugfs_remove_recursive() in gpio_la_poll_remove() does not
wait for an in-flight trigger_write(). The blob_lock taken there does not
help, because trigger_write() never takes it. A write that races an unbind
therefore writes into freed memory:
trigger_write() gpio_la_poll_remove()
priv = m->private
buf = memdup_user() [may sleep]
mutex_lock(&priv->blob_lock)
debugfs_remove_recursive() [no wait]
mutex_unlock(&priv->blob_lock)
(remove returns; devres frees priv)
priv->trig_data = buf <-- use-after-free write
priv->trig_len = count
The race is reachable by root via
/sys/bus/platform/drivers/gpio-sloppy-logic-analyzer/unbind.
Create "trigger" with debugfs_create_file() instead. Its full_proxy
wrapper makes debugfs_remove_recursive() drain any in-flight ->write
before it returns.
The use-after-free is confirmed under KASAN with a minimal reproducer of
the same debugfs_create_file_unsafe() plus devm_kzalloc() pattern
(available on request); it produces a slab-use-after-free write in the
handler.
Advisories
No advisories yet.
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Wed, 26 Aug 2026 16:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-416 |
Wed, 26 Aug 2026 14:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: gpio: sloppy-logic-analyzer: fix use-after-free via debugfs trigger on unbind The "trigger" debugfs file has a hand-rolled ->write handler (trigger_write()) that dereferences the per-device gpio_la_poll_priv. The file is created with debugfs_create_file_unsafe(), and the handler never takes a debugfs reference. Nothing keeps the object alive while the handler runs. priv is allocated with devm_kzalloc(). devres frees it when the platform device is unbound. debugfs_create_file_unsafe() installs no full_proxy wrapper, so debugfs_remove_recursive() in gpio_la_poll_remove() does not wait for an in-flight trigger_write(). The blob_lock taken there does not help, because trigger_write() never takes it. A write that races an unbind therefore writes into freed memory: trigger_write() gpio_la_poll_remove() priv = m->private buf = memdup_user() [may sleep] mutex_lock(&priv->blob_lock) debugfs_remove_recursive() [no wait] mutex_unlock(&priv->blob_lock) (remove returns; devres frees priv) priv->trig_data = buf <-- use-after-free write priv->trig_len = count The race is reachable by root via /sys/bus/platform/drivers/gpio-sloppy-logic-analyzer/unbind. Create "trigger" with debugfs_create_file() instead. Its full_proxy wrapper makes debugfs_remove_recursive() drain any in-flight ->write before it returns. The use-after-free is confirmed under KASAN with a minimal reproducer of the same debugfs_create_file_unsafe() plus devm_kzalloc() pattern (available on request); it produces a slab-use-after-free write in the handler. | |
| Title | gpio: sloppy-logic-analyzer: fix use-after-free via debugfs trigger on unbind | |
| 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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Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-08-26T14:37:27.759Z
Reserved: 2026-08-26T14:34:25.767Z
Link: CVE-2026-80563
No data.
Status : Received
Published: 2026-08-26T15:17:11.310
Modified: 2026-08-26T15:17:11.310
Link: CVE-2026-80563
No data.
OpenCVE Enrichment
Updated: 2026-08-26T17:45:03Z
Weaknesses