In Ashlar-Vellum Cobalt, Xenon, Argon, Lithium, and Cobalt Share versions prior to 12.6.1204.204, the affected applications lack proper validation of user-supplied data when parsing XE files. This could lead to a heap-based buffer overflow. An attacker could leverage this vulnerability to execute arbitrary code in the context of the current process.
In Ashlar-Vellum Cobalt, Xenon, Argon, Lithium, and Cobalt Share versions prior to 12.6.1204.204, the affected applications lack proper validation of user-supplied data when parsing VC6 files. This could lead to a heap-based buffer overflow. An attacker could leverage this vulnerability to execute arbitrary code in the context of the current process.
In Ashlar-Vellum Cobalt, Xenon, Argon, Lithium, and Cobalt Share versions prior to 12.6.1204.204, the affected applications lack proper validation of user-supplied data when parsing CO files. This could lead to an out-of-bounds write. An attacker could leverage this vulnerability to execute arbitrary code in the context of the current process.
In Ashlar-Vellum Cobalt, Xenon, Argon, Lithium, and Cobalt Share versions prior to 12.6.1204.204, the affected applications lack proper validation of user-supplied data when parsing AR files. This could lead to an out-of-bounds read. An attacker could leverage this vulnerability to execute arbitrary code in the context of the current process.
OpenFGA is a high-performance and flexible authorization/permission engine built for developers and inspired by Google Zanzibar. OpenFGA v1.9.3 to v1.9.4 ( openfga-0.2.40 <= Helm chart <= openfga-0.2.41, v1.9.3 <= docker <= v.1.9.4) are vulnerable to improper policy enforcement when certain Check and ListObject calls are executed. This vulnerability is fixed in 1.9.5.
** UNSUPPORTED WHEN ASSIGNED ** Improper Neutralization of Expression/Command Delimiters vulnerability in Apache Commons OGNL.
This issue affects Apache Commons OGNL: all versions.
When using the API Ognl.getValue, the OGNL engine parses and evaluates the provided expression with powerful capabilities, including accessing and invoking related methods,
etc. Although OgnlRuntime attempts to restrict certain dangerous classes and methods (such as java.lang.Runtime) through a blocklist, these restrictions are not comprehensive.
Attackers may be able to bypass the restrictions by leveraging class objects that are not covered by the blocklist and potentially achieve arbitrary code execution.
As this project is retired, we do not plan to release a version that fixes this issue. Users are recommended to find an alternative or restrict access to the instance to trusted users.
NOTE: This vulnerability only affects products that are no longer supported by the maintainer.
A reflected cross-site scripting (XSS) vulnerability in the Liferay Portal 7.4.0 through 7.4.3.132, and Liferay DXP 2025.Q1.0 through 2025.Q1.8, 2024.Q4.0 through 2024.Q4.7, 2024.Q3.1 through 2024.Q3.13, 2024.Q2.0 through 2024.Q2.13, 2024.Q1.1 through 2024.Q1.16 and 7.4 GA through update 92 allows an remote authenticated user to inject JavaScript in message board threads and categories.
Meshtastic is an open source mesh networking solution. Prior to v2.6.3, an attacker can send NodeInfo with a empty publicKey first, then overwrite it with a new key. First sending a empty key bypasses 'if (p.public_key.size > 0) {', clearing the existing publicKey (and resetting the size to 0) for a known node. Then a new key bypasses 'if (info->user.public_key.size > 0) {', and this malicious key is stored in NodeDB. This vulnerability is fixed in 2.6.3.
ColdFusion versions 2025.1, 2023.13, 2021.19 and earlier are affected by a Server-Side Request Forgery (SSRF) vulnerability that could lead to limited file system read. A high-privilege authenticated attacker can force the application to make arbitrary requests via injection of arbitrary URLs. Exploitation of this issue does not require user interaction.
Liferay Portal 7.4.0 through 7.4.3.132, and Liferay DXP 2025.Q1.0 through 2025.Q1.10, 2024.Q4.0 through 2024.Q4.7, 2024.Q3.1 through 2024.Q3.13, 2024.Q2.1 through 2024.Q2.13, 2024.Q1.1 through 2024.Q1.17 and 7.4 GA through update 92 is vulnerable to Insecure Direct Object Reference (IDOR) in the groupId parameter of the _com_liferay_roles_selector_web_portlet_RolesSelectorPortlet_groupId. When an organization administrator modifies this parameter id value, they can gain unauthorized access to user lists from other organizations.
A reflected cross-site scripting (XSS) vulnerability in the Liferay Portal 7.4.3.132, and Liferay DXP 2025.Q1.0 through 2025.Q1.7 allows a remote authenticated attacker to inject JavaScript code via the content page's name field. This malicious payload is then reflected and executed within the user's browser when viewing the "document View Usages" page.
A vulnerability was detected in ThingsBoard 4.1. This vulnerability affects unknown code of the component Add Gateway Handler. The manipulation leads to improper neutralization of special elements used in a template engine. The attack can be initiated remotely. The exploit has been disclosed to the public and may be used. The vendor replies, that "[t]he fix will come within upcoming release (v4.2) and will be inherited by maintenance releases of LTS versions (starting 4.0)."
A security issue was discovered in the Kubernetes Image Builder where default credentials are enabled during the Windows image build process when using the Nutanix or VMware OVA providers. These credentials, which allow root access, are disabled at the conclusion of the build. Kubernetes clusters are only affected if their nodes use VM images created via the Image Builder project and the vulnerability was exploited during the build process, which requires an attacker to access the build VM and modify the image while the build is in progress.
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: validate command request size
In commit 2b9b8f3b68ed ("ksmbd: validate command payload size"), except
for SMB2_OPLOCK_BREAK_HE command, the request size of other commands
is not checked, it's not expected. Fix it by add check for request
size of other commands.
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix wrong next length validation of ea buffer in smb2_set_ea()
There are multiple smb2_ea_info buffers in FILE_FULL_EA_INFORMATION request
from client. ksmbd find next smb2_ea_info using ->NextEntryOffset of
current smb2_ea_info. ksmbd need to validate buffer length Before
accessing the next ea. ksmbd should check buffer length using buf_len,
not next variable. next is the start offset of current ea that got from
previous ea.
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix out of bounds read in smb2_sess_setup
ksmbd does not consider the case of that smb2 session setup is
in compound request. If this is the second payload of the compound,
OOB read issue occurs while processing the first payload in
the smb2_sess_setup().
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: validate session id and tree id in the compound request
This patch validate session id and tree id in compound request.
If first operation in the compound is SMB2 ECHO request, ksmbd bypass
session and tree validation. So work->sess and work->tcon could be NULL.
If secound request in the compound access work->sess or tcon, It cause
NULL pointer dereferecing error.
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix out-of-bound read in smb2_write
ksmbd_smb2_check_message doesn't validate hdr->NextCommand. If
->NextCommand is bigger than Offset + Length of smb2 write, It will
allow oversized smb2 write length. It will cause OOB read in smb2_write.
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: not allow guest user on multichannel
This patch return STATUS_NOT_SUPPORTED if binding session is guest.
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: call rcu_barrier() in ksmbd_server_exit()
racy issue is triggered the bug by racing between closing a connection
and rmmod. In ksmbd, rcu_barrier() is not called at module unload time,
so nothing prevents ksmbd from getting unloaded while it still has RCU
callbacks pending. It leads to trigger unintended execution of kernel
code locally and use to defeat protections such as Kernel Lockdown
In the Linux kernel, the following vulnerability has been resolved:
mptcp: plug races between subflow fail and subflow creation
We have races similar to the one addressed by the previous patch between
subflow failing and additional subflow creation. They are just harder to
trigger.
The solution is similar. Use a separate flag to track the condition
'socket state prevent any additional subflow creation' protected by the
fallback lock.
The socket fallback makes such flag true, and also receiving or sending
an MP_FAIL option.
The field 'allow_infinite_fallback' is now always touched under the
relevant lock, we can drop the ONCE annotation on write.
In the Linux kernel, the following vulnerability has been resolved:
virtio-net: fix recursived rtnl_lock() during probe()
The deadlock appears in a stack trace like:
virtnet_probe()
rtnl_lock()
virtio_config_changed_work()
netdev_notify_peers()
rtnl_lock()
It happens if the VMM sends a VIRTIO_NET_S_ANNOUNCE request while the
virtio-net driver is still probing.
The config_work in probe() will get scheduled until virtnet_open() enables
the config change notification via virtio_config_driver_enable().
In the Linux kernel, the following vulnerability has been resolved:
ipv6: mcast: Delay put pmc->idev in mld_del_delrec()
pmc->idev is still used in ip6_mc_clear_src(), so as mld_clear_delrec()
does, the reference should be put after ip6_mc_clear_src() return.
In the Linux kernel, the following vulnerability has been resolved:
efivarfs: Fix memory leak of efivarfs_fs_info in fs_context error paths
When processing mount options, efivarfs allocates efivarfs_fs_info (sfi)
early in fs_context initialization. However, sfi is associated with the
superblock and typically freed when the superblock is destroyed. If the
fs_context is released (final put) before fill_super is called—such as
on error paths or during reconfiguration—the sfi structure would leak,
as ownership never transfers to the superblock.
Implement the .free callback in efivarfs_context_ops to ensure any
allocated sfi is properly freed if the fs_context is torn down before
fill_super, preventing this memory leak.
In the Linux kernel, the following vulnerability has been resolved:
hwmon: (corsair-cpro) Validate the size of the received input buffer
Add buffer_recv_size to store the size of the received bytes.
Validate buffer_recv_size in send_usb_cmd().
In the Linux kernel, the following vulnerability has been resolved:
iio: adc: axp20x_adc: Add missing sentinel to AXP717 ADC channel maps
The AXP717 ADC channel maps is missing a sentinel entry at the end. This
causes a KASAN warning.
Add the missing sentinel entry.
In the Linux kernel, the following vulnerability has been resolved:
atm: clip: Fix memory leak of struct clip_vcc.
ioctl(ATMARP_MKIP) allocates struct clip_vcc and set it to
vcc->user_back.
The code assumes that vcc_destroy_socket() passes NULL skb
to vcc->push() when the socket is close()d, and then clip_push()
frees clip_vcc.
However, ioctl(ATMARPD_CTRL) sets NULL to vcc->push() in
atm_init_atmarp(), resulting in memory leak.
Let's serialise two ioctl() by lock_sock() and check vcc->push()
in atm_init_atmarp() to prevent memleak.
In the Linux kernel, the following vulnerability has been resolved:
net: ethernet: ti: am65-cpsw-nuss: Fix skb size by accounting for skb_shared_info
While transitioning from netdev_alloc_ip_align() to build_skb(), memory
for the "skb_shared_info" member of an "skb" was not allocated. Fix this
by allocating "PAGE_SIZE" as the skb length, accounting for the packet
length, headroom and tailroom, thereby including the required memory space
for skb_shared_info.
In the Linux kernel, the following vulnerability has been resolved:
rxrpc: Fix bug due to prealloc collision
When userspace is using AF_RXRPC to provide a server, it has to preallocate
incoming calls and assign to them call IDs that will be used to thread
related recvmsg() and sendmsg() together. The preallocated call IDs will
automatically be attached to calls as they come in until the pool is empty.
To the kernel, the call IDs are just arbitrary numbers, but userspace can
use the call ID to hold a pointer to prepared structs. In any case, the
user isn't permitted to create two calls with the same call ID (call IDs
become available again when the call ends) and EBADSLT should result from
sendmsg() if an attempt is made to preallocate a call with an in-use call
ID.
However, the cleanup in the error handling will trigger both assertions in
rxrpc_cleanup_call() because the call isn't marked complete and isn't
marked as having been released.
Fix this by setting the call state in rxrpc_service_prealloc_one() and then
marking it as being released before calling the cleanup function.
In the Linux kernel, the following vulnerability has been resolved:
drm/tegra: nvdec: Fix dma_alloc_coherent error check
Check for NULL return value with dma_alloc_coherent, in line with
Robin's fix for vic.c in 'drm/tegra: vic: Fix DMA API misuse'.
In the Linux kernel, the following vulnerability has been resolved:
net: appletalk: Fix device refcount leak in atrtr_create()
When updating an existing route entry in atrtr_create(), the old device
reference was not being released before assigning the new device,
leading to a device refcount leak. Fix this by calling dev_put() to
release the old device reference before holding the new one.
In the Linux kernel, the following vulnerability has been resolved:
wifi: mt76: mt7925: Fix null-ptr-deref in mt7925_thermal_init()
devm_kasprintf() returns NULL on error. Currently, mt7925_thermal_init()
does not check for this case, which results in a NULL pointer
dereference.
Add NULL check after devm_kasprintf() to prevent this issue.
In the Linux kernel, the following vulnerability has been resolved:
HID: quirks: Add quirk for 2 Chicony Electronics HP 5MP Cameras
The Chicony Electronics HP 5MP Cameras (USB ID 04F2:B824 & 04F2:B82C)
report a HID sensor interface that is not actually implemented.
Attempting to access this non-functional sensor via iio_info causes
system hangs as runtime PM tries to wake up an unresponsive sensor.
Add these 2 devices to the HID ignore list since the sensor interface is
non-functional by design and should not be exposed to userspace.
In the Linux kernel, the following vulnerability has been resolved:
tracing: Add down_write(trace_event_sem) when adding trace event
When a module is loaded, it adds trace events defined by the module. It
may also need to modify the modules trace printk formats to replace enum
names with their values.
If two modules are loaded at the same time, the adding of the event to the
ftrace_events list can corrupt the walking of the list in the code that is
modifying the printk format strings and crash the kernel.
The addition of the event should take the trace_event_sem for write while
it adds the new event.
Also add a lockdep_assert_held() on that semaphore in
__trace_add_event_dirs() as it iterates the list.
In the Linux kernel, the following vulnerability has been resolved:
dmaengine: nbpfaxi: Fix memory corruption in probe()
The nbpf->chan[] array is allocated earlier in the nbpf_probe() function
and it has "num_channels" elements. These three loops iterate one
element farther than they should and corrupt memory.
The changes to the second loop are more involved. In this case, we're
copying data from the irqbuf[] array into the nbpf->chan[] array. If
the data in irqbuf[i] is the error IRQ then we skip it, so the iterators
are not in sync. I added a check to ensure that we don't go beyond the
end of the irqbuf[] array. I'm pretty sure this can't happen, but it
seemed harmless to add a check.
On the other hand, after the loop has ended there is a check to ensure
that the "chan" iterator is where we expect it to be. In the original
code we went one element beyond the end of the array so the iterator
wasn't in the correct place and it would always return -EINVAL. However,
now it will always be in the correct place. I deleted the check since
we know the result.
In the Linux kernel, the following vulnerability has been resolved:
net: phy: Don't register LEDs for genphy
If a PHY has no driver, the genphy driver is probed/removed directly in
phy_attach/detach. If the PHY's ofnode has an "leds" subnode, then the
LEDs will be (un)registered when probing/removing the genphy driver.
This could occur if the leds are for a non-generic driver that isn't
loaded for whatever reason. Synchronously removing the PHY device in
phy_detach leads to the following deadlock:
rtnl_lock()
ndo_close()
...
phy_detach()
phy_remove()
phy_leds_unregister()
led_classdev_unregister()
led_trigger_set()
netdev_trigger_deactivate()
unregister_netdevice_notifier()
rtnl_lock()
There is a corresponding deadlock on the open/register side of things
(and that one is reported by lockdep), but it requires a race while this
one is deterministic.
Generic PHYs do not support LEDs anyway, so don't bother registering
them.
In the Linux kernel, the following vulnerability has been resolved:
net: airoha: fix potential use-after-free in airoha_npu_get()
np->name was being used after calling of_node_put(np), which
releases the node and can lead to a use-after-free bug.
Previously, of_node_put(np) was called unconditionally after
of_find_device_by_node(np), which could result in a use-after-free if
pdev is NULL.
This patch moves of_node_put(np) after the error check to ensure
the node is only released after both the error and success cases
are handled appropriately, preventing potential resource issues.
In the Linux kernel, the following vulnerability has been resolved:
phy: tegra: xusb: Fix unbalanced regulator disable in UTMI PHY mode
When transitioning from USB_ROLE_DEVICE to USB_ROLE_NONE, the code
assumed that the regulator should be disabled. However, if the regulator
is marked as always-on, regulator_is_enabled() continues to return true,
leading to an incorrect attempt to disable a regulator which is not
enabled.
This can result in warnings such as:
[ 250.155624] WARNING: CPU: 1 PID: 7326 at drivers/regulator/core.c:3004
_regulator_disable+0xe4/0x1a0
[ 250.155652] unbalanced disables for VIN_SYS_5V0
To fix this, we move the regulator control logic into
tegra186_xusb_padctl_id_override() function since it's directly related
to the ID override state. The regulator is now only disabled when the role
transitions from USB_ROLE_HOST to USB_ROLE_NONE, by checking the VBUS_ID
register. This ensures that regulator enable/disable operations are
properly balanced and only occur when actually transitioning to/from host
mode.
In the Linux kernel, the following vulnerability has been resolved:
netfs: Fix copy-to-cache so that it performs collection with ceph+fscache
The netfs copy-to-cache that is used by Ceph with local caching sets up a
new request to write data just read to the cache. The request is started
and then left to look after itself whilst the app continues. The request
gets notified by the backing fs upon completion of the async DIO write, but
then tries to wake up the app because NETFS_RREQ_OFFLOAD_COLLECTION isn't
set - but the app isn't waiting there, and so the request just hangs.
Fix this by setting NETFS_RREQ_OFFLOAD_COLLECTION which causes the
notification from the backing filesystem to put the collection onto a work
queue instead.
In the Linux kernel, the following vulnerability has been resolved:
net: libwx: fix the using of Rx buffer DMA
The wx_rx_buffer structure contained two DMA address fields: 'dma' and
'page_dma'. However, only 'page_dma' was actually initialized and used
to program the Rx descriptor. But 'dma' was uninitialized and used in
some paths.
This could lead to undefined behavior, including DMA errors or
use-after-free, if the uninitialized 'dma' was used. Althrough such
error has not yet occurred, it is worth fixing in the code.
In the Linux kernel, the following vulnerability has been resolved:
iio: common: st_sensors: Fix use of uninitialize device structs
Throughout the various probe functions &indio_dev->dev is used before it
is initialized. This caused a kernel panic in st_sensors_power_enable()
when the call to devm_regulator_bulk_get_enable() fails and then calls
dev_err_probe() with the uninitialized device.
This seems to only cause a panic with dev_err_probe(), dev_err(),
dev_warn() and dev_info() don't seem to cause a panic, but are fixed
as well.
The issue is reported and traced here: [1]
In the Linux kernel, the following vulnerability has been resolved:
comedi: pcl812: Fix bit shift out of bounds
When checking for a supported IRQ number, the following test is used:
if ((1 << it->options[1]) & board->irq_bits) {
However, `it->options[i]` is an unchecked `int` value from userspace, so
the shift amount could be negative or out of bounds. Fix the test by
requiring `it->options[1]` to be within bounds before proceeding with
the original test. Valid `it->options[1]` values that select the IRQ
will be in the range [1,15]. The value 0 explicitly disables the use of
interrupts.
In the Linux kernel, the following vulnerability has been resolved:
comedi: aio_iiro_16: Fix bit shift out of bounds
When checking for a supported IRQ number, the following test is used:
if ((1 << it->options[1]) & 0xdcfc) {
However, `it->options[i]` is an unchecked `int` value from userspace, so
the shift amount could be negative or out of bounds. Fix the test by
requiring `it->options[1]` to be within bounds before proceeding with
the original test. Valid `it->options[1]` values that select the IRQ
will be in the range [1,15]. The value 0 explicitly disables the use of
interrupts.
In the Linux kernel, the following vulnerability has been resolved:
bpf: Reject %p% format string in bprintf-like helpers
static const char fmt[] = "%p%";
bpf_trace_printk(fmt, sizeof(fmt));
The above BPF program isn't rejected and causes a kernel warning at
runtime:
Please remove unsupported %\x00 in format string
WARNING: CPU: 1 PID: 7244 at lib/vsprintf.c:2680 format_decode+0x49c/0x5d0
This happens because bpf_bprintf_prepare skips over the second %,
detected as punctuation, while processing %p. This patch fixes it by
not skipping over punctuation. %\x00 is then processed in the next
iteration and rejected.
In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix use-after-free in cifs_oplock_break
A race condition can occur in cifs_oplock_break() leading to a
use-after-free of the cinode structure when unmounting:
cifs_oplock_break()
_cifsFileInfo_put(cfile)
cifsFileInfo_put_final()
cifs_sb_deactive()
[last ref, start releasing sb]
kill_sb()
kill_anon_super()
generic_shutdown_super()
evict_inodes()
dispose_list()
evict()
destroy_inode()
call_rcu(&inode->i_rcu, i_callback)
spin_lock(&cinode->open_file_lock) <- OK
[later] i_callback()
cifs_free_inode()
kmem_cache_free(cinode)
spin_unlock(&cinode->open_file_lock) <- UAF
cifs_done_oplock_break(cinode) <- UAF
The issue occurs when umount has already released its reference to the
superblock. When _cifsFileInfo_put() calls cifs_sb_deactive(), this
releases the last reference, triggering the immediate cleanup of all
inodes under RCU. However, cifs_oplock_break() continues to access the
cinode after this point, resulting in use-after-free.
Fix this by holding an extra reference to the superblock during the
entire oplock break operation. This ensures that the superblock and
its inodes remain valid until the oplock break completes.
In the Linux kernel, the following vulnerability has been resolved:
ice: add NULL check in eswitch lag check
The function ice_lag_is_switchdev_running() is being called from outside of
the LAG event handler code. This results in the lag->upper_netdev being
NULL sometimes. To avoid a NULL-pointer dereference, there needs to be a
check before it is dereferenced.
In the Linux kernel, the following vulnerability has been resolved:
rxrpc: Fix irq-disabled in local_bh_enable()
The rxrpc_assess_MTU_size() function calls down into the IP layer to find
out the MTU size for a route. When accepting an incoming call, this is
called from rxrpc_new_incoming_call() which holds interrupts disabled
across the code that calls down to it. Unfortunately, the IP layer uses
local_bh_enable() which, config dependent, throws a warning if IRQs are
enabled:
WARNING: CPU: 1 PID: 5544 at kernel/softirq.c:387 __local_bh_enable_ip+0x43/0xd0
...
RIP: 0010:__local_bh_enable_ip+0x43/0xd0
...
Call Trace:
<TASK>
rt_cache_route+0x7e/0xa0
rt_set_nexthop.isra.0+0x3b3/0x3f0
__mkroute_output+0x43a/0x460
ip_route_output_key_hash+0xf7/0x140
ip_route_output_flow+0x1b/0x90
rxrpc_assess_MTU_size.isra.0+0x2a0/0x590
rxrpc_new_incoming_peer+0x46/0x120
rxrpc_alloc_incoming_call+0x1b1/0x400
rxrpc_new_incoming_call+0x1da/0x5e0
rxrpc_input_packet+0x827/0x900
rxrpc_io_thread+0x403/0xb60
kthread+0x2f7/0x310
ret_from_fork+0x2a/0x230
ret_from_fork_asm+0x1a/0x30
...
hardirqs last enabled at (23): _raw_spin_unlock_irq+0x24/0x50
hardirqs last disabled at (24): _raw_read_lock_irq+0x17/0x70
softirqs last enabled at (0): copy_process+0xc61/0x2730
softirqs last disabled at (25): rt_add_uncached_list+0x3c/0x90
Fix this by moving the call to rxrpc_assess_MTU_size() out of
rxrpc_init_peer() and further up the stack where it can be done without
interrupts disabled.
It shouldn't be a problem for rxrpc_new_incoming_call() to do it after the
locks are dropped as pmtud is going to be performed by the I/O thread - and
we're in the I/O thread at this point.
In the Linux kernel, the following vulnerability has been resolved:
rxrpc: Fix recv-recv race of completed call
If a call receives an event (such as incoming data), the call gets placed
on the socket's queue and a thread in recvmsg can be awakened to go and
process it. Once the thread has picked up the call off of the queue,
further events will cause it to be requeued, and once the socket lock is
dropped (recvmsg uses call->user_mutex to allow the socket to be used in
parallel), a second thread can come in and its recvmsg can pop the call off
the socket queue again.
In such a case, the first thread will be receiving stuff from the call and
the second thread will be blocked on call->user_mutex. The first thread
can, at this point, process both the event that it picked call for and the
event that the second thread picked the call for and may see the call
terminate - in which case the call will be "released", decoupling the call
from the user call ID assigned to it (RXRPC_USER_CALL_ID in the control
message).
The first thread will return okay, but then the second thread will wake up
holding the user_mutex and, if it sees that the call has been released by
the first thread, it will BUG thusly:
kernel BUG at net/rxrpc/recvmsg.c:474!
Fix this by just dequeuing the call and ignoring it if it is seen to be
already released. We can't tell userspace about it anyway as the user call
ID has become stale.