In the Linux kernel, the following vulnerability has been resolved:
media: nxp: imx8-isi: Add missing v4l2_subdev_cleanup() in crossbar and pipe
Both mxc_isi_crossbar_init() and mxc_isi_pipe_init() call
v4l2_subdev_init_finalize() which allocates the subdev active state,
but neither mxc_isi_crossbar_cleanup() nor mxc_isi_pipe_cleanup()
calls v4l2_subdev_cleanup() to free it.
This causes a memory leak on every rmmod, reported by kmemleak:
unreferenced object 0xffff0000d06fc800 (size 192):
comm "(udev-worker)", pid 254, jiffies 4294913455
backtrace (crc 36eeae58):
kmemleak_alloc+0x34/0x40
__kvmalloc_node_noprof+0x5f8/0x7d8
__v4l2_subdev_state_alloc+0x1fc/0x30c
__v4l2_subdev_init_finalize+0x178/0x368
Add the missing v4l2_subdev_cleanup() calls before media_entity_cleanup()
in both crossbar and pipe cleanup paths.
In the Linux kernel, the following vulnerability has been resolved:
media: nxp: imx8-isi: Fix potential out-of-bounds issues
The maximum downscaling factor supported by ISI can be up to 16. Add
minimum value constraint before applying the setting to hardware.
Otherwise, the process will not respond even when Ctrl+C is executed.
In the Linux kernel, the following vulnerability has been resolved:
media: pci: dm1105: Free allocated workqueue
Destroy allocated workqueue in remove() callback to free its resources,
thus fixing memory leak.
In the Linux kernel, the following vulnerability has been resolved:
media: pwc: Drain fill_buf on start_streaming() failure
pwc_isoc_init() submits its isochronous URBs with
usb_submit_urb(.., GFP_KERNEL) in a loop. After the first URB is
submitted, its completion handler pwc_isoc_handler() can run on another
CPU before the loop finishes:
start_streaming()
pwc_isoc_init()
usb_submit_urb(urbs[0], GFP_KERNEL)
pwc_isoc_handler(urbs[0])
pdev->fill_buf =
pwc_get_next_fill_buf(pdev)
usb_submit_urb(urbs[i>0], ..) -> fails
pwc_isoc_cleanup(pdev) /* kills URBs */
return ret;
pwc_cleanup_queued_bufs(pdev, VB2_BUF_STATE_QUEUED)
pwc_get_next_fill_buf() detaches a buffer from pdev->queued_bufs and
stores it in pdev->fill_buf. The error path in start_streaming() only
drains pdev->queued_bufs, so the buffer parked in pdev->fill_buf is
leaked. vb2_start_streaming() then triggers
WARN_ON(owned_by_drv_count).
stop_streaming() already handles this since commit 80b0963e1698
("[media] pwc: fix WARN_ON"), which added the fill_buf drain in the
teardown path but not in the start_streaming() error path. Mirror that
handling on failure so start_streaming() returns with no buffer owned
by the driver.
Issue identified by automated review of the INV-003 series at
https://sashiko.dev/
In the Linux kernel, the following vulnerability has been resolved:
media: pwc: Return queued buffers on start_streaming() failure
The vb2 framework hands buffers to the driver via buf_queue() before
calling start_streaming(). If start_streaming() returns an error
without first returning those buffers via vb2_buffer_done(),
vb2_start_streaming() fires WARN_ON(owned_by_drv_count) and the queued
buffers leak.
pwc's start_streaming() had two early returns that hit this trap:
-ENODEV when the USB device was already disconnected, and -ERESTARTSYS
when mutex_lock_interruptible() was interrupted by a signal. Call the
existing pwc_cleanup_queued_bufs() helper with VB2_BUF_STATE_QUEUED
before returning (matching the state already used by the
pwc_isoc_init() error path in the same function).
This mirrors the uvcvideo fix in commit 4cf3b6fd54eb ("media: uvcvideo:
Return queued buffers on start_streaming() failure").
In the Linux kernel, the following vulnerability has been resolved:
media: radio-si476x: Unregister v4l2_device on probe failure
si476x_radio_probe() registers radio->v4l2dev before allocating the V4L2
controls and before registering the video device. If any of those later
steps fails, probe returns through the exit label after freeing only the
control handler.
A failed probe does not call si476x_radio_remove(), so the
v4l2_device_unregister() there is not reached. This leaves the parent
device reference taken by v4l2_device_register() behind on the error path.
Unregister the V4L2 device in the probe error path after freeing the
controls.
In the Linux kernel, the following vulnerability has been resolved:
media: rtl2832: fix use-after-free in rtl2832_remove()
cancel_delayed_work_sync() is called before i2c_mux_del_adapters()
in rtl2832_remove(). While the cancel waits for any running instance
of i2c_gate_work to finish, it does not prevent the timer from being
rescheduled by a concurrent thread.
During probe, the r820t_attach() call attempts I2C transfers through
the mux adapter. These transfers go through i2c_mux_master_xfer(),
which calls rtl2832_deselect() after the transfer completes,
rescheduling i2c_gate_work via schedule_delayed_work(). If this
transfer is still in flight when rtl2832_remove() runs,
rtl2832_deselect() can reschedule i2c_gate_work after it has been
cancelled, causing a use-after-free when kfree(dev) is called.
Fix this by calling i2c_mux_del_adapters() before
cancel_delayed_work_sync(). Once the mux adapter is unregistered, no
new I2C transfers can go through it, so rtl2832_deselect() can no
longer reschedule i2c_gate_work. The subsequent
cancel_delayed_work_sync() is then guaranteed to be final.
In the Linux kernel, the following vulnerability has been resolved:
media: rtl2832_sdr: Return queued buffers on start_streaming() failure
The vb2 framework hands buffers to the driver via buf_queue() before
calling start_streaming(). If start_streaming() returns an error
without first returning those buffers via vb2_buffer_done(),
vb2_start_streaming() fires WARN_ON(owned_by_drv_count) and the queued
buffers leak.
rtl2832_sdr_start_streaming() had multiple error paths that hit this
trap: two direct early returns (-ENODEV, -ERESTARTSYS), plus six
`goto err` paths covering subdev s_power, tuner setup, ADC setup,
stream-buffer allocation, urb allocation, and urb submission failures.
None of them returned the queued buffers.
The original function had no distinct success exit and fell straight
through into the err label, which previously only did mutex_unlock and
"return ret". Adding queued-buffer cleanup at err must therefore be
paired with an explicit success return; otherwise every successful
start would also drain the buffer queue and kill streaming. Add that
success return, then add rtl2832_sdr_cleanup_queued_bufs() at the err
label and before each early return.
The cleanup helper takes a vb2_buffer_state argument so that the
start_streaming error paths can pass VB2_BUF_STATE_QUEUED (as
expected by userspace on start_streaming failure) while stop_streaming
keeps its existing VB2_BUF_STATE_ERROR semantics.
This mirrors the uvcvideo fix in commit 4cf3b6fd54eb ("media: uvcvideo:
Return queued buffers on start_streaming() failure").
The err label still does not roll back power_ctrl(), frontend_ctrl(),
the POWER_ON flag, or stream/URB allocations that may have happened
before the failing step. Those are pre-existing leaks of a different
class and are not addressed here.
In the Linux kernel, the following vulnerability has been resolved:
media: saa7134: Fix a possible memory leak in saa7134_video_init1
In saa7134_video_init1(), the return value of the first
saa7134_pgtable_alloc() is not checked. If it fails, the function
continues as if successful, leaving the driver with an invalid page
table. Additionally, if vb2_queue_init() for the VBI queue fails after
the video queue page table has been allocated, the allocated memory is
not freed before returning. The second saa7134_pgtable_alloc() also
lacks a return value check. Errors occur during device probing before
the device is fully registered, the normal cleanup path in
saa7134_finidev() is not executed, leading to memory leaks and
potential use of uninitialized DMA resources.
Check the return value of both saa7134_pgtable_alloc() calls and
propagate errors. On failure of any later step, free allocated page
tables to avoid memory leaks. Ensure control handlers are also
released on error to prevent further resource leakage.
Found by code review.
In the Linux kernel, the following vulnerability has been resolved:
media: stm32-dcmipp: Return queued buffers on start_streaming() failure
The vb2 framework hands buffers to the driver via buf_queue() before
calling start_streaming(). If start_streaming() returns an error
without first returning those buffers via vb2_buffer_done(),
vb2_start_streaming() fires WARN_ON(owned_by_drv_count) and the queued
buffers leak.
dcmipp_bytecap_start_streaming() returned -EINVAL when the source
subdevice could not be resolved from the media graph, before
pm_runtime_resume_and_get() and media_pipeline_start() had been called.
The remaining error paths already converge on the err_buffer_done
label, which calls dcmipp_bytecap_all_buffers_done(...,
VB2_BUF_STATE_QUEUED). Jump to that label directly: the intermediate
err_pm_put / err_media_pipeline_stop labels are skipped, which is
correct because nothing they would undo has happened yet.
This mirrors the uvcvideo fix in commit 4cf3b6fd54eb ("media: uvcvideo:
Return queued buffers on start_streaming() failure").
In the Linux kernel, the following vulnerability has been resolved:
media: stm32: dcmi: unregister notifier on probe failure
dcmi_graph_init() registers the async notifier before dcmi_probe() toggles
the reset line. If reset_control_assert() or reset_control_deassert()
fails afterwards, probe returns through err_cleanup and the driver core
will not call dcmi_remove().
Unregister the notifier before cleaning it up on that error path,
matching the successful remove path and the V4L2 async notifier lifetime
rules.
[hverkuil: added Fixes tag]
In the Linux kernel, the following vulnerability has been resolved:
media: sun4i-csi: Return queued buffers on start_streaming() failure
The vb2 framework hands buffers to the driver via buf_queue() before
calling start_streaming(). If start_streaming() returns an error
without first returning those buffers via vb2_buffer_done(),
vb2_start_streaming() fires WARN_ON(owned_by_drv_count) and the queued
buffers leak.
sun4i_csi_start_streaming() returned -EINVAL when no matching CSI
format could be found, before any setup (scratch buffer allocation,
pipeline start) had been performed. The remaining error paths already
converge on the err_clear_dma_queue label, which calls
return_all_buffers(..., VB2_BUF_STATE_QUEUED) under csi->qlock. Jump
to that label directly: the intermediate err_disable_device /
err_disable_pipeline / err_free_scratch_buffer labels are skipped,
which is correct because nothing they would undo has happened yet.
This mirrors the uvcvideo fix in commit 4cf3b6fd54eb ("media: uvcvideo:
Return queued buffers on start_streaming() failure").
In the Linux kernel, the following vulnerability has been resolved:
media: ti: vpe: Fix the error code of devm_kzalloc() in vip_probe_slice()
In vip_probe_slice(), the error check for devm_kzalloc() incorrectly
uses PTR_ERR_OR_ZERO() which returns 0 for NULL pointer.
Return -ENOMEM for devm_kzalloc() failure.
In the Linux kernel, the following vulnerability has been resolved:
media: ti: vpe: unwind v4l2 device registration on probe error
If the vpe_top resource is missing, vpe_probe() returns -ENODEV after
v4l2_device_register() has succeeded. Probe failures do not call the
driver's remove callback, so the v4l2 device remains registered on that
error path.
Route that failure through the existing v4l2_device_unregister() unwind
label, matching the other errors after v4l2_device_register().
In the Linux kernel, the following vulnerability has been resolved:
media: v4l2-ctrls: validate HEVC active reference counts
HEVC slice parameters are shared stateless V4L2 controls, but the common
validation path does not verify the active L0/L1 reference counts before
driver-specific code consumes them.
The original report came from Cedrus, but the active count bounds are
not Cedrus-specific. Validate them in the common HEVC slice control path
so stateless HEVC drivers get the same basic guarantees as soon as the
control is queued.
Do not reject ref_idx_l0/ref_idx_l1 entries here. Existing userspace may
use out-of-range sentinel values such as 0xff for missing references, and
some hardware can use that information for concealment. Keep this common
check limited to the active reference counts.
In the Linux kernel, the following vulnerability has been resolved:
media: v4l2-fwnode: Fix subdev owner overwritten in v4l2_async_register_subdev_sensor()
The v4l2 helper v4l2_async_register_subdev_sensor() calls
v4l2_async_register_subdev(), which is a macro that expands to
__v4l2_async_register_subdev(sd,THIS_MODULE). Since the macro is expanded
inside v4l2-fwnode.c, THIS_MODULE resolves to the v4l2-fwnode module
rather than the sensor driver module that originally set sd->owner. When
v4l2-fwnode is built-in, THIS_MODULE evaluates to NULL, which then
overwrites the sensor driver's owner with NULL.
This causes the problem that the sensor module's reference count is never
incremented during async registration, so the module can be removed while
the subdevice is still in use by a notifier (e.g., a CSI-2 receiver
bridge driver).
Fix this by renaming v4l2_async_register_subdev_sensor() to
__v4l2_async_register_subdev_sensor() with an added explicit module
argument and introducing a wrapper macro:
#define v4l2_async_register_subdev_sensor(sd) \
__v4l2_async_register_subdev_sensor(sd, THIS_MODULE)
This ensures the sensor driver module is properly referenced even when
the sensor driver does not init the owner field before calling
v4l2_async_register_subdev_sensor() and prevents premature module removal.
In the Linux kernel, the following vulnerability has been resolved:
media: vivid: check for vb2_is_busy() when toggling caps
The vivid_update_format_cap/out() functions must only be called if the
capture/output queue are not busy. But for the controls that select
the CROP/COMPOSE/SCALE capability that is not checked.
Only when streaming starts will they be set to 'grabbed' and it is
impossible to change the control, but between REQBUFS and STREAMON you
are still allowed to set these controls. Since vivid_update_format_cap/out
will change the format, this can cause unexpected results.
Besides adding these checks, also add a WARN_ON in
vivid_update_format_cap/out() if the queue is busy.
I'm 90% certain that this is the cause of this syzbot bug:
https://syzkaller.appspot.com/bug?extid=dac8f5eaa46837e97b89
But since we never have reproducers, it is hard to be certain. In any case,
these checks are needed regardless.
In the Linux kernel, the following vulnerability has been resolved:
media: vivid: fix cleanup bugs in vivid_init()
When platform_device_register() fails in vivid_init(), the embedded
struct device in vivid_pdev has already been initialized by
device_initialize(), but the failure path jumps to free_output_strings
without dropping the device reference for the current platform device:
vivid_init()
-> platform_device_register(&vivid_pdev)
-> device_initialize(&vivid_pdev.dev)
-> setup_pdev_dma_masks(&vivid_pdev)
-> platform_device_add(&vivid_pdev)
This leads to a reference leak when platform_device_register() fails.
Fix this by calling platform_device_put() before jumping to the common
cleanup path.
Also, the unreg_driver label incorrectly calls
platform_driver_register() instead of platform_driver_unregister(),
which breaks cleanup when workqueue creation fails after successful
driver registration. Fix that as well.
The reference leak was identified by a static analysis tool I developed
and confirmed by manual review. The incorrect cleanup call was found
during code inspection.
In the Linux kernel, the following vulnerability has been resolved:
ALSA: seq: close a re-opened queue timer in the destructor
queue_delete() closes the queue timer, then frees it. snd_seq_timer_close()
clears q->timer->timeri. snd_use_lock_sync() then drains borrowers, and
snd_seq_timer_delete() frees q->timer.
A borrower can re-open the timer inside that window. A SET_QUEUE_CLIENT
that took a queueptr() use_lock reference before the queue was unlinked
runs snd_seq_timer_open() after the close. Open refuses re-open only while
timeri is set, and the close just cleared it, so it re-opens timeri.
snd_seq_timer_delete() does not close that instance. Its snd_seq_timer_stop()
is a no-op, because running was cleared first. So it frees q->timer with the
instance still live. The queue is freed next.
The instance stays on the global timer with callback_data pointing at the
freed queue. A non-owner START on the unlocked queue arms it. The next tick
derefs the freed queue in snd_seq_timer_interrupt().
Reachable by an unprivileged user with access to /dev/snd/seq. No CAP and
no queue ownership required.
Close any lingering instance in the destructor. There, ->timeri can no
longer change: the queue is unlinked and all use_lock borrowers have
drained, so no snd_seq_queue_use() can re-open it. Close it before clearing
q->timer. snd_timer_close() waits for any in-flight snd_seq_timer_interrupt()
to finish, and that callback still reads q->timer (via snd_seq_check_queue()),
so q->timer must stay valid until it drains.
In the Linux kernel, the following vulnerability has been resolved:
ALSA: timer: drain a slave's callback before its master detaches it
snd_timer_close_locked() drains the closing instance's own in-flight
callback (IFLG_CALLBACK) before freeing it, but not its slaves'. When a
master instance is closed, remove_slave_links() clears each slave's
->timer; the slave's own close then reads timer == NULL and takes the
branch that skips the drain entirely (snd_timer_stop_slave() also no-ops
on a NULL timer). So a slave whose callback is still running when the
master is closed is freed underneath the live callback, leading to
use-after-free.
Drain the slaves too before remove_slave_links() severs them.
snd_timer_stop() has already taken this instance off the active list, so
no new slave callback can be queued. Take the slaves off the ack list so
a pending one can't fire either, then wait for any that is already in
flight.
In the Linux kernel, the following vulnerability has been resolved:
ALSA: timer: don't re-enter an instance callback that is still running
The userspace-driven timer (utimer) TRIGGER ioctl calls
snd_timer_interrupt() directly with no serialization, so two threads
triggering the same utimer can run snd_timer_interrupt() on one
snd_timer concurrently.
snd_timer_process_callbacks() drops timer->lock around each instance
callback and marks the in-flight callback with the single
SNDRV_TIMER_IFLG_CALLBACK bit; snd_timer_close_locked() waits on that
bit to drain an in-flight callback before freeing the instance. The bit
cannot represent two concurrent callbacks: when a second interrupt
re-queues an instance whose callback is still running, both run at once,
the first to finish clears the bit, and the close-path drain then frees
the instance (and its callback_data) while the other callback is still
live - a use-after-free reachable by any user able to open
/dev/snd/timer, both via a user timer instance and via a sequencer queue
timer bound to the utimer.
snd_timer_interrupt() sets IFLG_CALLBACK before dropping timer->lock, so
a concurrent interrupt already observes it under the lock. Skip
re-queuing an instance (and its slaves) to the ack/sack list while its
callback is in flight; the accumulated pticks are delivered on the next
tick, so no event is lost.
In the Linux kernel, the following vulnerability has been resolved:
wifi: ath6kl: fix OOB access from firmware ADDBA window size
aggr_recv_addba_req_evt() logs a debug message when the firmware-supplied
win_sz is outside [AGGR_WIN_SZ_MIN, AGGR_WIN_SZ_MAX] but does not
return. The out-of-range win_sz is then used in TID_WINDOW_SZ() to
compute a kzalloc size and stored in rxtid->hold_q_sz, leading to
zero-size or overflowed allocations and subsequent out-of-bounds access.
Clean up any previously active aggregation session for the TID first,
then return early when win_sz is out of the valid range, instead of
proceeding with a broken allocation size.
In the Linux kernel, the following vulnerability has been resolved:
wifi: ath6kl: fix use-after-free in aggr_reset_state()
The aggr_reset_state() function uses timer_delete() (non-synchronous)
for the aggregation timer before proceeding to delete TID state and
before the structure is freed by callers like aggr_module_destroy().
If the timer callback (aggr_timeout) is executing when aggr_reset_state()
is called, the callback will continue to access aggr_conn fields like
rx_tid[] and stat[] which may be freed immediately after by
kfree(aggr_info->aggr_conn) in aggr_module_destroy().
Additionally, the timer callback can re-arm itself via mod_timer() while
aggr_reset_state() is running, creating a more complex race condition.
Use timer_delete_sync() instead to ensure any running timer callback
has completed before returning.
In the Linux kernel, the following vulnerability has been resolved:
wifi: mwifiex: fix NULL dereference when the AP has HT-cap but no HT-oper
mwifiex_tdls_add_ht_oper() gates its follow-the-AP-bandwidth path on
bss_desc->bcn_ht_cap being present, but then dereferences a different
pointer, bss_desc->bcn_ht_oper:
if (ISSUPP_CHANWIDTH40(priv->adapter->hw_dot_11n_dev_cap) &&
bss_desc->bcn_ht_cap &&
ISALLOWED_CHANWIDTH40(bss_desc->bcn_ht_oper->ht_param))
bcn_ht_cap and bcn_ht_oper are populated independently while parsing the
associated AP's beacon in mwifiex_update_bss_desc_with_ie(): an AP that
advertises an HT Capabilities element but no HT Operation element leaves
bcn_ht_cap non-NULL and bcn_ht_oper NULL. Setting up a TDLS link to a
peer while associated to such an AP then dereferences the NULL
bcn_ht_oper and crashes the kernel. Every other bcn_ht_oper user in the
driver NULL-checks it first.
Guard on the pointer that is actually dereferenced.
Found by 0sec automated security-research tooling (https://0sec.ai).
In the Linux kernel, the following vulnerability has been resolved:
wifi: wilc1000: validate assoc response length before subtracting header
wilc_parse_assoc_resp_info() computes the trailing IE length as
ies_len = buffer_len - sizeof(*res);
without first checking that buffer_len is at least sizeof(struct
wilc_assoc_resp) (6 bytes). buffer_len is the length reported for a
received association response (host_int_parse_assoc_resp_info() passes
hif_drv->assoc_resp / assoc_resp_info_len straight in) and must be
validated before the driver accesses the fixed header.
For a frame shorter than the 6-byte fixed header, the subtraction wraps.
For a four-byte response the result is truncated to a u16 ies_len of
65534, so kmemdup() then attempts to copy 65534 bytes starting at
buffer + sizeof(*res), beyond the valid association-response data
(CWE-125). A response shorter than four bytes can also cause an
out-of-bounds read of res->status_code at offsets 2 and 3.
Reject frames too short to hold the fixed header before touching the
header or computing ies_len. Also set the connection status to a failure
on this path: the caller falls through to a
"conn_info->status == WLAN_STATUS_SUCCESS" check after the parser
returns, so leaving the status untouched could let a malformed short
response be treated as a successful association.
In the Linux kernel, the following vulnerability has been resolved:
wifi: mt76: mt7615: drop TXRX_NOTIFY on non-mmio buses
PKT_TYPE_TXRX_NOTIFY is an mmio-only event, but mt7615_rx_check() and
mt7615_queue_rx_skb() dispatch it to mt7615_mac_tx_free() on every bus.
mt7615_mac_tx_free() cleans the DMA tx queues with
mt76_queue_tx_cleanup(), which calls queue_ops->tx_cleanup(). Only the
mmio queue ops implement that callback; on the mt7663 USB and SDIO
buses it is NULL, so a TXRX_NOTIFY there calls a NULL pointer in the RX
worker. Same defect as the mt7921 and mt7925 patches in this series.
Drop the event on non-mmio buses via mt76_is_mmio(), as in
commit 5683e1488aa9 ("wifi: mt76: connac: do not check WED status for
non-mmio devices").
In the Linux kernel, the following vulnerability has been resolved:
wifi: mt76: mt7921: drop TXRX_NOTIFY on non-mmio buses
PKT_TYPE_TXRX_NOTIFY is an mmio-only event, but mt7921_rx_check() and
mt7921_queue_rx_skb() dispatch it to mt7921_mac_tx_free() on every bus.
mt7921_mac_tx_free() cleans the DMA tx queues with
mt76_queue_tx_cleanup(), which calls queue_ops->tx_cleanup(). Only the
mmio queue ops implement that callback; on USB and SDIO it is NULL, so
a TXRX_NOTIFY there calls a NULL pointer in the RX worker:
BUG: kernel NULL pointer dereference, address: 0000000000000000
RIP: 0010:0x0
Call Trace:
mt7921_mac_tx_free+0x64/0x310 [mt7921_common]
mt7921_rx_check+0x5f/0xf0 [mt7921_common]
mt76u_rx_worker+0x1b9/0x620 [mt76_usb]
Drop the event on non-mmio buses via mt76_is_mmio(), as in
commit 5683e1488aa9 ("wifi: mt76: connac: do not check WED status for
non-mmio devices").
In the Linux kernel, the following vulnerability has been resolved:
wifi: mt76: mt7925: drop TXRX_NOTIFY on non-mmio buses
PKT_TYPE_TXRX_NOTIFY is an mmio-only event, but mt7925_rx_check() and
mt7925_queue_rx_skb() dispatch it to mt7925_mac_tx_free() on every bus.
mt7925_mac_tx_free() cleans the DMA tx queues with
mt76_queue_tx_cleanup(), which calls queue_ops->tx_cleanup(). Only the
mmio queue ops implement that callback; on USB it is NULL, so a
TXRX_NOTIFY there calls a NULL pointer in the RX worker:
BUG: kernel NULL pointer dereference, address: 0000000000000000
RIP: 0010:0x0
Call Trace:
mt7925_mac_tx_free+0x58/0x350 [mt7925_common]
mt7925_rx_check+0xe2/0x130 [mt7925_common]
mt76u_rx_worker+0x1b9/0x620 [mt76_usb]
Drop the event on non-mmio buses via mt76_is_mmio(), as in
commit 5683e1488aa9 ("wifi: mt76: connac: do not check WED status for
non-mmio devices").
In the Linux kernel, the following vulnerability has been resolved:
wifi: brcmfmac: make release_scratchbuffers idempotent
brcmf_pcie_release_scratchbuffers() frees the shared.scratch and
shared.ringupd DMA buffers with dma_free_coherent() but does not clear
the pointers afterwards, unlike the sibling release_ringbuffers() which
NULLs commonrings/flowrings/idxbuf on release.
Both the bus_reset .reset callback (brcmf_pcie_reset) and
brcmf_pcie_remove() call release_scratchbuffers. When reset teardown
has run before removal, remove's own teardown would call
dma_free_coherent() a second time on the already-freed DMA allocation.
NULL the pointers after free, matching release_ringbuffers(), so a later
release observes that the allocation has already been released. This
patch makes repeated sequential release safe; the reset-work lifetime is
handled separately by the following patch.
This issue was found by an in-house static analysis tool.
In the Linux kernel, the following vulnerability has been resolved:
wifi: ath12k: fix NULL pointer dereference in rhash table destroy
When unbinding the ath12k driver, kernel NULL pointer dereferences
occur in irq_work_sync() called from rhashtable_destroy().
Two hash tables are affected:
1. ath12k_link_sta hash table in ath12k_base
2. ath12k_dp_link_peer hash table in ath12k_dp
The issue happens because the destroy functions are called unconditionally
in cleanup paths, but the hash tables are only initialized late in their
respective init functions. If the device was never fully started or if the
init functions failed before initializing the hash tables, the pointers
will be NULL. The issues are always reproducible from a VM because the MSI
addressing initialization is failing.
Call trace for ath12k_link_sta_rhash_tbl_destroy:
RIP: irq_work_sync+0x1e/0x70
rhashtable_destroy+0x12/0x60
ath12k_link_sta_rhash_tbl_destroy+0x19/0x40 [ath12k]
ath12k_core_stop+0xe/0x80 [ath12k]
ath12k_core_hw_group_cleanup+0x6b/0xb0 [ath12k]
ath12k_pci_remove+0x60/0x110 [ath12k]
Call trace for ath12k_dp_link_peer_rhash_tbl_destroy:
RIP: irq_work_sync+0x1e/0x70
rhashtable_destroy+0x12/0x60
ath12k_dp_link_peer_rhash_tbl_destroy+0x29/0x50 [ath12k]
ath12k_dp_cmn_device_deinit+0x21/0x140 [ath12k]
ath12k_core_hw_group_cleanup+0x6b/0xb0 [ath12k]
ath12k_pci_remove+0x60/0x110 [ath12k]
Fix this by adding NULL checks before calling rhashtable_destroy() in
both destroy functions.
The NULL check approach was chosen because the rhashtable pointer
serves as the initialization state indicator. The init can fail at
various points, leaving some components uninitialized. Checking the
pointer directly is simpler than adding separate state flags that
would need synchronization.
In the Linux kernel, the following vulnerability has been resolved:
staging: rtl8723bs: fix OOB reads in rtw_get_wps_ie()
rtw_get_wps_ie() iterates over IE data from network frames without
validating that the IE header and payload fit within the remaining
buffer before reading them. Specifically:
- in_ie[cnt + 1] is read without checking cnt + 1 < in_len
- memcmp(&in_ie[cnt + 2], ...) accesses cnt + 2 without bounds check
- in_ie[cnt + 1] is used as length without verifying payload fits
Add bounds checks at the top of the loop body to break early if fewer
than 2 bytes remain for the IE header, or if the declared payload
extends past the end of the buffer. Also require at least 4 bytes of
payload before comparing the WPS OUI.
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: hci_sync: Protect UUID list traversal
The hci_sync conversion moved class-of-device and EIR generation from an
HCI request built under hdev->lock to asynchronous command sync work.
The worker holds hdev->req_lock, but that lock does not serialize access
to hdev->uuids against add_uuid() and remove_uuid(), which update the
list under hdev->lock.
The following interleaving can therefore occur:
CPU0 (command sync work) CPU1 (management socket)
fetch uuid from the list
list_del(&uuid->list)
kfree(uuid)
read uuid->size
KASAN reports the resulting use-after-free:
BUG: KASAN: slab-use-after-free in eir_create+0xb8f/0xee0
Read of size 1 at addr ffff88810dbd8620 by task kworker/u17:0/87
Workqueue: hci0 hci_cmd_sync_work
Call Trace:
eir_create+0xb8f/0xee0
hci_update_eir_sync+0x1c0/0x330
hci_cmd_sync_work+0x13c/0x290
process_one_work+0x63a/0x1070
worker_thread+0x45b/0xd10
Allocated by task 86:
__kasan_kmalloc+0x8f/0xa0
add_uuid+0x18a/0x4b0
hci_sock_sendmsg+0x1033/0x1ea0
Freed by task 92:
__kasan_slab_free+0x43/0x70
kfree+0x131/0x3c0
remove_uuid+0x25e/0x560
hci_sock_sendmsg+0x1033/0x1ea0
Hold hdev->lock while generating and committing the class-of-device and
EIR snapshots. Release it before sending an HCI command, so controller
waits do not happen under the device lock. This protects all UUID list
walks in these paths and restores the serialization lost in the command
sync conversion.
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: RFCOMM: Fix session UAF in set_termios
rfcomm_tty_set_termios() tests dlc->session without rfcomm_mutex and
later passes the pointer to rfcomm_send_rpn(). The latter dereferences
both session->initiator and session->sock. Meanwhile, krfcommd can
unlink the DLC and free the session while holding rfcomm_mutex.
The race can proceed as follows:
TTY ioctl task krfcommd
-------------- --------
load dlc->session
enter rfcomm_send_rpn()
lock rfcomm_mutex
clear dlc->session
free session
unlock rfcomm_mutex
read session->initiator
KASAN reported:
BUG: KASAN: slab-use-after-free in rfcomm_send_rpn+0x297/0x2a0
Read of size 4 at addr ffff88810012a850 by task poc/92
Call Trace:
rfcomm_send_rpn+0x297/0x2a0
rfcomm_tty_set_termios+0x50d/0x850
tty_set_termios+0x596/0x950
set_termios+0x46a/0x6e0
tty_mode_ioctl+0x152/0xbd0
tty_ioctl+0x915/0x1240
__x64_sys_ioctl+0x134/0x1c0
Allocated by task 92:
rfcomm_session_add+0x9e/0x2e0
rfcomm_dlc_open+0x8b1/0xe00
rfcomm_dev_activate+0x85/0x1a0
rfcomm_tty_open+0x90/0x280
Freed by task 68:
kfree+0x131/0x3c0
rfcomm_session_del+0x119/0x180
rfcomm_run+0x737/0x4710
Add rfcomm_dlc_send_rpn(), which holds rfcomm_mutex while it verifies
that the DLC is still attached and sends the RPN frame. Have the TTY
path use the helper and drop its unlocked session check. This keeps the
session valid through both the frame construction and socket send.
In the Linux kernel, the following vulnerability has been resolved:
exec: fix unsigned loop counter wrap in transfer_args_to_stack()
The stop value is derived from bprm->p >> PAGE_SHIFT. The index variable
is an unsigned long. If bprm->p drops below PAGE_SIZE and stop becomes
zero the loop condition index >= stop is always true.
After the index == 0 iteration the decrement wraps to ULONG_MAX and
bprm->page[ULONG_MAX] reads sizeof(void *) bytes in front of the array.
The pointer has wrapped to -1. That garbage pointer is then passed to
kmap_local_page() and PAGE_SIZE bytes are copied from wherever that
lands into the stack of the process being created. And the loop doesn't
terminate either...
Getting there only requires bprm->p < PAGE_SIZE. On !MMU
bprm_set_stack_limit() and bprm_hit_stack_limit() are empty. So the only
constraint on how far bprm->p is pushed down is valid_arg_len(), i.e.
that each individual string still fits in what is left.
bprm->p starts at PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *) so a
single argument or environment string of a little over 31 pages leaves
it in the first page:
Oops - load access fault [#1]
CPU: 0 UID: 0 PID: 1 Comm: victim Not tainted 7.2.0-rc4 #1
epc : __memcpy+0xd4/0xf8
ra : transfer_args_to_stack+0xaa/0xae
s4 : ffffffffffffffff s2 : 0000000000000000
a1 : ffffffdc98000000 a2 : 0000000000001000
status: 0000000a00001880 badaddr: ffffffdc98000000 cause: 0000000000000005
[<801a5324>] __memcpy+0xd4/0xf8
[<800d5f6a>] load_flat_binary+0x43a/0x65e
[<800a2de4>] bprm_execve+0x1d4/0x316
[<800a351a>] do_execveat_common+0x12e/0x138
[<800a3d44>] __riscv_sys_execve+0x38/0x4e
Kernel panic - not syncing: Fatal exception in interrupt
This is an arcane bug but we should still fix it.
Count down from MAX_ARG_PAGES so the loop ends when index reaches stop,
stop == 0 included. The iterations performed are unchanged for every
other value of stop.
Only CONFIG_MMU=n builds are affected, transfer_args_to_stack() is used
by binfmt_flat and binfmt_elf_fdpic on nommu only.
The loop predates git history. commit 7e7ec6a93434
("elf_fdpic_transfer_args_to_stack(): make it generic") only moved it
from binfmt_elf_fdpic.c into fs/exec.c and narrowed the copy to the used
part of the first page. The condition and the decrement are unchanged
from 2.6.12-rc2.
In the Linux kernel, the following vulnerability has been resolved:
binfmt_misc: set have_execfd only once the interpreter is opened
load_misc_binary() raises bprm->have_execfd as soon as it sees the 'O'
(or 'C') flag. This happens well before it opens the interpreter. If
that open fails the flag stays set on the bprm. binfmt_misc is at the
head of the format list so an interpreter open failure that returns
-ENOEXEC lets the search fall through to a later format. This means it
runs the matched binary directly having never staged an interpreter. So
bprm->executable is NULL while have_execfd falsely claims a descriptor
is present.
Consequently, begin_new_exec() dereferences the missing executable:
would_dump(bprm, bprm->executable);
and NULL derefs. Had it not, the hand-off later in the same function
would have failed anyway. FD_ADD(0, bprm->executable) rejects a NULL
file with -ENOMEM. Both sites are past the point of no return so the
exec cannot be unwound either way.
This can be reached by unprivileged users as binfmt_misc can be mounted
in user namespaces. So a user can register an 'O' entry whose
interpreter lives on a FUSE mount, have the FUSE server fail the open
with -ENOEXEC and execute a native ELF file that matches the entry.
have_execfd only means anything alongside the executable it describes
which is not set until the interpreter has been opened and staged.
So lets raise it there, next to execfd_creds, which is already set at
that point. An open failure now leaves it clear, so the fallback format
derives credentials from the binary and emits no AT_EXECFD, as it would
for any native exec. The argv rewrite load_misc_binary() performs before
the open is still not undone. This means the binary sees the interpreter
path in argv[0] and its own path in argv[1] but that predates this
change and only became observable once the exec stopped faulting.
In the Linux kernel, the following vulnerability has been resolved:
LoongArch: Move jump_label_init() before parse_early_param()
When enabling both CONFIG_MEM_ALLOC_PROFILING=y and
CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT=y, then diabling memory
profiling by adding the boot parameter 'sysctl.vm.mem_profiling=0' will
cause the kernel failed to boot.
After analysis, this is because jump_label_init() must be called before
parse_early_param(), the early param handlers may modify static keys by
static_branch_enable/disable().
Fix this by moving jump_label_init() to before parse_early_param(). The
solution is similar to other architectures.
In the Linux kernel, the following vulnerability has been resolved:
cdrom: fix stack out-of-bounds read in CDROMVOLCTRL
mmc_ioctl_cdrom_volume() first reads the audio control mode page into a
32-byte stack buffer with cgc->buflen set to 24. If the device reports a
block descriptor, the function increases cgc->buflen to include that
descriptor and reads the page again.
For CDROMVOLCTRL, the function then builds a MODE SELECT parameter list
by moving cgc->buffer forward by offset - 8 bytes. This drops the block
descriptor from the outgoing payload and leaves a new 8-byte mode
parameter header in front of the audio control page. However, cgc->buflen
is left unchanged.
With a standard 8-byte block descriptor, cgc->buffer points at buffer + 8
but cgc->buflen remains 32. cdrom_mode_select() therefore asks the low
level packet path to write 32 bytes from that adjusted pointer, reading 8
bytes past the end of the 32-byte stack buffer.
This is not hit by CDROMVOLREAD, and CDROMVOLCTRL only triggers it on
drives that return a non-zero block descriptor length, which helps explain
why it has gone unnoticed. The overread is also sent to the device as
extra MODE SELECT payload, so it may not produce an obvious local failure.
Reduce cgc->buflen by the same amount as the buffer pointer adjustment so
the MODE SELECT transfer covers only the intended parameter list.
In the Linux kernel, the following vulnerability has been resolved:
firmware: stratix10-svc: fix memory leaks and list corruption bugs
Fix a memory leak when gen_pool_alloc() fails by freeing pmem on the error
path. Switch pmem allocation from devm_kzalloc() to kzalloc() with
explicit kfree() in the free path to match its list-managed lifetime.
Remove the erroneous list_del(&svc_data_mem) which corrupted the list head
on failed lookups.
In the Linux kernel, the following vulnerability has been resolved:
comedi: comedi_parport: deal with premature interrupt
Syzbot reported a general protection fault in
`comedi_get_is_subdevice_running()`, which was called from the interrupt
handler `parport_interrupt()` in the "comedi_parport" driver, but it
does not currently have a C reproducer for the problem. It's
probably due to a premature interrupt for one of two reasons:
1. The driver sets up the interrupt handler before the comedi subdevices
used by the interrupt handler have been allocated, but does not
disable the interrupt in the parallel port's CTRL register first.
2. The driver uses a user-supplied I/O port base address which Syzbot
would have supplied, but it might not be backed by real parallel port
hardware.
Change the initialization order in the driver's comedi "attach" handler
(`parport_attach()`) so that the hardware registers are initialized
before the interrupt handler is requested. This should prevent
premature interrupts occurring for real hardware.
Also add a test to the interrupt handler to ensure the comedi device is
fully attached and return early if it isn't.
In the Linux kernel, the following vulnerability has been resolved:
mei: bus: access mei_device under device_lock on cleanup
Fix couple of problems in mei_cl_bus_dev_release():
mei_cl_flush_queues() is running without lock.
bus->file_list access after mei_dev_bus_put(bus) can become a
use-after-free if this was the last reference to bus.
Protect queues cleanup and WARN traversal by device lock there
to avoid the concurrent access problems.
Move WARN traversal before mei_dev_bus_put(bus).
This file uses bus variable name for mei_device, adjust
code of mei_cl_bus_dev_release() to use bus variable too.
In the Linux kernel, the following vulnerability has been resolved:
intel_th: fix MSC output device reference leak
intel_th_output_open() looks up the output device with
bus_find_device_by_devt(), which returns the device with a reference that
must be dropped after use.
commit 95fc36a234da ("intel_th: fix device leak on output open()")
attempted to drop the reference from intel_th_output_release(). However,
a successful open replaces file->f_op with the output driver file
operations before returning, so close runs the output driver release
callback instead.
For MSC outputs, close runs intel_th_msc_release(), which only removes
the per-file iterator and does not drop the device reference taken by
intel_th_output_open(). Consequently, every successful MSC output open
leaks one device reference.
Drop the device reference from intel_th_msc_release(), which is the
release path actually used for MSC output files. Remove the now-unused
intel_th_output_release() callback from intel_th_output_fops.
In the Linux kernel, the following vulnerability has been resolved:
misc: nsm: only unlock nsm_dev on post-lock error paths
nsm_dev_ioctl() jumps to the common out label even when the initial
copy_from_user() fails before nsm->lock has been taken. The error path
then blindly unlocks a mutex that was never acquired.
This issue was found by our static analysis tool and then manually
reviewed against the current tree.
The grounded PoC kept the miscdevice ioctl entry and the pre-lock
copy_from_user(&raw, argp, _IOC_SIZE(cmd)) failure path by issuing
NSM_IOCTL_RAW with an invalid user pointer. That failure reaches the
shared out label before mutex_lock(&nsm->lock). Lockdep reported:
WARNING: bad unlock balance detected!
exploit/193 is trying to release lock (&global_nsm.lock) at:
nsm_dev_ioctl+0x5f/0xcf [vuln_msv]
but there are no more locks to release!
no locks held by exploit/193.
Return immediately on the pre-lock copy_from_user() failure and keep the
common unlock label for the post-lock paths only.
In the Linux kernel, the following vulnerability has been resolved:
misc: nsm: pin the module while the device is open
misc_open() installs a misc driver's file operations with fops_get(),
which pins file_operations::owner before replacing the file's f_op. The
NSM misc device leaves nsm_dev_fops.owner unset, so opening /dev/nsm does
not take a module reference on the nsm driver.
If the driver is built as a module, an open file descriptor can therefore
survive rmmod of the module that provides its ioctl callbacks. A later
ioctl through that descriptor can call into unloaded module text.
Set nsm_dev_fops.owner to THIS_MODULE so the misc core holds the module
while any /dev/nsm file descriptor is open, matching the lifetime
expectation for the installed file operations.
In the Linux kernel, the following vulnerability has been resolved:
tracing: Delay module ref count for "enable_event" trigger
Triggers are now delayed from freeing, but can still be triggered until
after the RCU grace period has ended. The freeing of the enable_event data
is put into the private_data_free() callback, but the put of the module
refcount is done immediately.
It is possible that if a module is removed that has an event that would
enable (or disable) it is still active, it can read the data of the module
after it is removed causing a use-after-free bug.
Move the trace_event_put_ref() that releases the module into the delayed
callback so that the module can not be removed until any reference to its
events are finished.
In the Linux kernel, the following vulnerability has been resolved:
tracing: Fix mmiotrace possible NULL dereferencing of hiter->dev
If the mmio_pipe_open() fails to find a PCI device, the hiter->dev
will be assigned to NULL. The mmiotrace read() function dereferences the
hiter->dev if hiter exists.
Change the test of the read to not only check hiter being NULL, but also
the hiter->dev before dereferencing it.
In the Linux kernel, the following vulnerability has been resolved:
tracing: Fix resource leak on mmiotrace trace_pipe close
The mmiotrace tracer was added May 12th 2008. At that time, resources
created in pipe_open() could not be freed because there was not
pipe_close function pointer of the tracer. The pipe_close function pointer
was added in December 7th, 2009, but the mmiotrace tracer was not updated.
mmio_pipe_open() allocates a header_iter and takes a pci_dev reference
when trace_pipe is opened. mmio_close() frees them, but it was only
wired to the tracer's .close callback.
tracing_release_pipe() invokes .pipe_close, not .close, when the
trace_pipe file is released. As a result, closing trace_pipe with the
mmiotrace tracer active leaked the header_iter allocation and left a
stale pci_dev reference.
Set .pipe_close to mmio_close, matching how function_graph wires both
callbacks to the same handler.
Note, if the trace_pipe is read to completion, it will clean up the
resources, but if one were to run:
# head -n 1 /sys/kernel/tracing/trace_pipe
VERSION 20070824
Over and over again, it would trigger a massive leak.
In the Linux kernel, the following vulnerability has been resolved:
tracing: Fix union collision of module and refcnt for dynamic events
In 'struct trace_event_call', the 'module' pointer and the 'refcnt'
atomic variable share the same memory space in a union. For dynamic
events, the union member is 'refcnt', which acts as an active
reference counter.
When a dynamic event (such as kprobe, uprobe, fprobe, eprobe, or
wprobe) has a non-zero reference count (e.g. due to active event
triggers or perf attachments), its 'call->module' evaluates to a
small non-zero integer instead of NULL.
When filtering or setting events for a specific module (e.g., writing
':mod:<module>' to 'set_event'), the code in
'__ftrace_set_clr_event_nolock()' and 'update_event_fields()' reads
'call->module' directly without checking whether the event is dynamic.
This causes the kernel to treat the small integer (refcnt) as a
'struct module' pointer, leading to a NULL/invalid pointer dereference
(Oops) when dereferencing the module name.
Fix this by ensuring that the 'TRACE_EVENT_FL_DYNAMIC' flag is checked
before treating 'call->module' as a valid pointer in these code paths.
In the Linux kernel, the following vulnerability has been resolved:
ublk: wait on ublk_dev_ready() instead of ub->completion
ub->completion is only re-armed by a successful START_USER_RECOVERY. If
the ublk server sends END_USER_RECOVERY without one - e.g. its START
failed with -EBUSY and the error was ignored - the wait is satisfied by
the stale completion of the previous recovery cycle, and the device is
marked LIVE and the requeue list kicked while the FETCH stream is still
running and ubq->canceling is still set. The kick redispatches a
previously requeued request, __ublk_queue_rq_common() sees ->canceling
and parks it again via __ublk_abort_rq(), and after the last FETCH
clears ->canceling nothing ever kicks the requeue list again: the
request is stranded there while holding its tag. If it is the flush
machinery's flush_rq, every subsequent fsync piles up in uninterruptible
sleep and teardown hangs on tag draining. This matches a report of a
lost PREFLUSH with ext4 on top of ublk after daemon crash recovery.
ub->completion is an edge-triggered latch used as a proxy for the level
condition "every queue has fetched all I/O commands", which can regress
(F_BATCH's UNPREP, daemon death) and whose re-arm can be skipped. Drop
it and wait on the real condition instead: the new helper
ublk_wait_dev_ready_and_lock() waits on ublk_dev_ready() via
wait_var_event_interruptible(), woken from ublk_mark_io_ready(), then
re-checks it under ub->mutex, waiting again on regression, and returns
with the mutex held and readiness guaranteed.
Readiness becomes true in the same ub->mutex critical section that
clears the last queue's ->canceling, so END_USER_RECOVERY marks the
device LIVE and kicks the requeue list strictly after ->canceling
clears. The wait stays interruptible, so a server whose daemon died can
still be signalled out. For ublk_ctrl_start_dev() this replaces the
fail-fast -EINVAL on an F_BATCH ready->UNPREP regression with waiting
until the device is ready again.
In the Linux kernel, the following vulnerability has been resolved:
arm64: make huge_ptep_get handled unaligned addresses
huge_ptep_get() can be handed a virtual address pointing to the middle
of a contpmd/contpte mapped hugetlb folio (examples of callers are
pagemap_hugetlb_range, page_mapped_in_vma).
The arm64 helper rewalks the pgtables in find_num_contig to answer
whether the huge pte we have maps a contpmd or a contpte hugetlb folio,
and returns CONT_PMDS or CONT_PTES, so that it can collect a/d bits over
the contiguous ptes. We can falsely return CONT_PTES instead of
CONT_PMDS if the addr is not aligned. On systems where CONT_PTES !=
CONT_PMDS (meaning page size is 16K), we could collect excess A/D bit
state, meaning extra work for the kernel. Even worse, we may iterate
beyond the PTE table and dereference a garbage ptep pointer to access
physical memory we don't own. Since the ptep pointer is a linear map
address, we may run off the end of the linear map or into a hole,
dereference a VA not mapped into the kernel pgtables and cause kernel
panic.
Fix this by aligning the pmdp pointer down to a contpmd base before
checking equality with the passed huge pte pointer, to correctly answer
whether the huge pte is the base of a contpmd block.
In the Linux kernel, the following vulnerability has been resolved:
arm64: syscall: Ensure saved x0 is kept in-sync with tracer updates
When seccomp support was originally added to arm64 in a1ae65b21941
("arm64: add seccomp support"), seccomp was erroneously called _before_
the ptrace syscall-enter-stop and therefore the tracer could trivially
manipulate the syscall register state after the seccomp check had
passed. This was subsequently fixed in a5cd110cb836 ("arm64/ptrace: run
seccomp after ptrace") by moving the seccomp check after the tracer has
run. Unfortunately, a decade later, that fix has been reported to be
incomplete.
On arm64, both the first argument to a syscall and its eventual return
value are allocated to register x0. In order to facilitate syscall
restarting and querying of syscall arguments on the syscall exit path,
the original value of x0 is stashed in 'struct pt_regs::orig_x0' early
during the syscall entry path and is returned for the first argument by
syscall_get_arguments(). Unlike 32-bit Arm, this stashed value is not
directly exposed via ptrace() and so changes to register x0 made by the
tracer on a syscall-enter-stop are not reflected in 'orig_x0'. This
means that seccomp, syscall tracepoints and audit can observe a stale
value for the register compared to the argument that will be observed by
the actual syscall.
Re-sync 'orig_x0' from x0 on the syscall entry path following a
potential ptrace stop (i.e. PTRACE_EVENTMSG_SYSCALL_ENTRY or
SECCOMP_RET_TRACE). This behaviour is limited to native tasks (because
compat tasks expose 'orig_r0' to ptrace) where the syscall is not being
skipped (because x0 is updated to hold the return value of -ENOSYS in
that case).