| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
crypto: atmel-sha204a - Fix potential UAF and memory leak in remove path
Unregister the hwrng to prevent new ->read() calls and flush the Atmel
I2C workqueue before teardown to prevent a potential UAF if a queued
callback runs while the device is being removed.
Drop the early return to ensure sysfs entries are removed and
->hwrng.priv is freed, preventing a memory leak. |
| In the Linux kernel, the following vulnerability has been resolved:
media: amphion: Fix race between m2m job_abort and device_run
Fix kernel panic caused by race condition where v4l2_m2m_ctx_release()
frees m2m_ctx while v4l2_m2m_try_run() is about to call device_run
with the same context.
Race sequence:
v4l2_m2m_try_run(): v4l2_m2m_ctx_release():
lock/unlock v4l2_m2m_cancel_job()
job_abort()
v4l2_m2m_job_finish()
kfree(m2m_ctx) <- frees ctx
device_run() <- use-after-free crash at 0x538
Crash trace:
Unable to handle kernel read from unreadable memory at virtual address
0000000000000538
v4l2_m2m_try_run+0x78/0x138
v4l2_m2m_device_run_work+0x14/0x20
The amphion vpu driver does not rely on the m2m framework's device_run
callback to perform encode/decode operations.
Fix the race by preventing m2m framework job scheduling entirely:
- Add job_ready callback returning 0 (no jobs ready for m2m framework)
- Remove job_abort callback to avoid the race condition |
| In the Linux kernel, the following vulnerability has been resolved:
net/smc: avoid early lgr access in smc_clc_wait_msg
A CLC decline can be received while the handshake is still in an early
stage, before the connection has been associated with a link group.
The decline handling in smc_clc_wait_msg() updates link-group level sync
state for first-contact declines, but that state only exists after link
group setup has completed. Guard the link-group update accordingly and
keep the per-socket peer diagnosis handling unchanged.
This preserves the existing sync_err handling for established link-group
contexts and avoids touching link-group state before it is available. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: nSVM: Sync interrupt shadow to cached vmcb12 after VMRUN of L2
After VMRUN in guest mode, nested_sync_control_from_vmcb02() syncs
fields written by the CPU from vmcb02 to the cached vmcb12. This is
because the cached vmcb12 is used as the authoritative copy of some of
the controls, and is the payload when saving/restoring nested state.
int_state is also written by the CPU, specifically bit 0 (i.e.
SVM_INTERRUPT_SHADOW_MASK) for nested VMs, but it is not sync'd to
cached vmcb12. This does not cause a problem if KVM_SET_NESTED_STATE
preceeds KVM_SET_VCPU_EVENTS in the restore path, as an interrupt shadow
would be correctly restored to vmcb02 (KVM_SET_VCPU_EVENTS overwrites
what KVM_SET_NESTED_STATE restored in int_state).
However, if KVM_SET_VCPU_EVENTS preceeds KVM_SET_NESTED_STATE, an
interrupt shadow would be restored into vmcb01 instead of vmcb02. This
would mostly be benign for L1 (delays an interrupt), but not for L2. For
L2, the vCPU could hang (e.g. if a wakeup interrupt is delivered before
a HLT that should have been in an interrupt shadow).
Sync int_state to the cached vmcb12 in nested_sync_control_from_vmcb02()
to avoid this problem. With that, KVM_SET_NESTED_STATE restores the
correct interrupt shadow state, and if KVM_SET_VCPU_EVENTS follows it
would overwrite it with the same value. |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: nfnetlink_osf: fix divide-by-zero in OSF_WSS_MODULO
nf_osf_match_one() computes ctx->window % f->wss.val in the
OSF_WSS_MODULO branch with no guard for f->wss.val == 0. A
CAP_NET_ADMIN user can add such a fingerprint via nfnetlink; a
subsequent matching TCP SYN divides by zero and panics the kernel.
Reject the bogus fingerprint in nfnl_osf_add_callback() above the
per-option for-loop. f->wss is per-fingerprint, not per-option, so
the check must run regardless of f->opt_num (including 0). Also
reject wss.wc >= OSF_WSS_MAX; nf_osf_match_one() already treats that
as "should not happen".
Crash:
Oops: divide error: 0000 [#1] SMP KASAN NOPTI
RIP: 0010:nf_osf_match_one (net/netfilter/nfnetlink_osf.c:98)
Call Trace:
<IRQ>
nf_osf_match (net/netfilter/nfnetlink_osf.c:220)
xt_osf_match_packet (net/netfilter/xt_osf.c:32)
ipt_do_table (net/ipv4/netfilter/ip_tables.c:348)
nf_hook_slow (net/netfilter/core.c:622)
ip_local_deliver (net/ipv4/ip_input.c:265)
ip_rcv (include/linux/skbuff.h:1162)
__netif_receive_skb_one_core (net/core/dev.c:6181)
process_backlog (net/core/dev.c:6642)
__napi_poll (net/core/dev.c:7710)
net_rx_action (net/core/dev.c:7945)
handle_softirqs (kernel/softirq.c:622) |
| In the Linux kernel, the following vulnerability has been resolved:
fbdev: tdfxfb: avoid divide-by-zero on FBIOPUT_VSCREENINFO
Much like commit 19f953e74356 ("fbdev: fb_pm2fb: Avoid potential divide
by zero error"), we also need to prevent that same crash from happening
in the udlfb driver as it uses pixclock directly when dividing, which
will crash. |
| In the Linux kernel, the following vulnerability has been resolved:
fbdev: udlfb: avoid divide-by-zero on FBIOPUT_VSCREENINFO
Much like commit 19f953e74356 ("fbdev: fb_pm2fb: Avoid potential divide
by zero error"), we also need to prevent that same crash from happening
in the udlfb driver as it uses pixclock directly when dividing, which
will crash. |
| In the Linux kernel, the following vulnerability has been resolved:
staging: sm750fb: fix division by zero in ps_to_hz()
ps_to_hz() is called from hw_sm750_crtc_set_mode() without validating
that pixclock is non-zero. A zero pixclock passed via FBIOPUT_VSCREENINFO
causes a division by zero.
Fix by rejecting zero pixclock in lynxfb_ops_check_var(), consistent
with other framebuffer drivers. |
| In the Linux kernel, the following vulnerability has been resolved:
ocfs2: fix use-after-free in ocfs2_fault() when VM_FAULT_RETRY
filemap_fault() may drop the mmap_lock before returning VM_FAULT_RETRY,
as documented in mm/filemap.c:
"If our return value has VM_FAULT_RETRY set, it's because the mmap_lock
may be dropped before doing I/O or by lock_folio_maybe_drop_mmap()."
When this happens, a concurrent munmap() can call remove_vma() and free
the vm_area_struct via RCU. The saved 'vma' pointer in ocfs2_fault() then
becomes a dangling pointer, and the subsequent trace_ocfs2_fault() call
dereferences it -- a use-after-free.
Fix this by saving ip_blkno as a plain integer before calling
filemap_fault(), and removing vma from the trace event. Since
ip_blkno is copied by value before the lock can be dropped, it
remains valid regardless of what happens to the vma or inode
afterward. |
| In the Linux kernel, the following vulnerability has been resolved:
PCI: endpoint: pci-epf-vntb: Stop cmd_handler work in epf_ntb_epc_cleanup
Disable the delayed work before clearing BAR mappings and doorbells to
avoid running the handler after resources have been torn down.
Unable to handle kernel paging request at virtual address ffff800083f46004
[...]
Internal error: Oops: 0000000096000007 [#1] SMP
[...]
Call trace:
epf_ntb_cmd_handler+0x54/0x200 [pci_epf_vntb] (P)
process_one_work+0x154/0x3b0
worker_thread+0x2c8/0x400
kthread+0x148/0x210
ret_from_fork+0x10/0x20 |
| In the Linux kernel, the following vulnerability has been resolved:
mm: blk-cgroup: fix use-after-free in cgwb_release_workfn()
cgwb_release_workfn() calls css_put(wb->blkcg_css) and then later accesses
wb->blkcg_css again via blkcg_unpin_online(). If css_put() drops the last
reference, the blkcg can be freed asynchronously (css_free_rwork_fn ->
blkcg_css_free -> kfree) before blkcg_unpin_online() dereferences the
pointer to access blkcg->online_pin, resulting in a use-after-free:
BUG: KASAN: slab-use-after-free in blkcg_unpin_online (./include/linux/instrumented.h:112 ./include/linux/atomic/atomic-instrumented.h:400 ./include/linux/refcount.h:389 ./include/linux/refcount.h:432 ./include/linux/refcount.h:450 block/blk-cgroup.c:1367)
Write of size 4 at addr ff11000117aa6160 by task kworker/71:1/531
Workqueue: cgwb_release cgwb_release_workfn
Call Trace:
<TASK>
blkcg_unpin_online (./include/linux/instrumented.h:112 ./include/linux/atomic/atomic-instrumented.h:400 ./include/linux/refcount.h:389 ./include/linux/refcount.h:432 ./include/linux/refcount.h:450 block/blk-cgroup.c:1367)
cgwb_release_workfn (mm/backing-dev.c:629)
process_scheduled_works (kernel/workqueue.c:3278 kernel/workqueue.c:3385)
Freed by task 1016:
kfree (./include/linux/kasan.h:235 mm/slub.c:2689 mm/slub.c:6246 mm/slub.c:6561)
css_free_rwork_fn (kernel/cgroup/cgroup.c:5542)
process_scheduled_works (kernel/workqueue.c:3302 kernel/workqueue.c:3385)
** Stack based on commit 66672af7a095 ("Add linux-next specific files
for 20260410")
I am seeing this crash sporadically in Meta fleet across multiple kernel
versions. A full reproducer is available at:
https://github.com/leitao/debug/blob/main/reproducers/repro_blkcg_uaf.sh
(The race window is narrow. To make it easily reproducible, inject a
msleep(100) between css_put() and blkcg_unpin_online() in
cgwb_release_workfn(). With that delay and a KASAN-enabled kernel, the
reproducer triggers the splat reliably in less than a second.)
Fix this by moving blkcg_unpin_online() before css_put(), so the
cgwb's CSS reference keeps the blkcg alive while blkcg_unpin_online()
accesses it. |
| In the Linux kernel, the following vulnerability has been resolved:
media: em28xx: fix use-after-free in em28xx_v4l2_open()
em28xx_v4l2_open() reads dev->v4l2 without holding dev->lock,
creating a race with em28xx_v4l2_init()'s error path and
em28xx_v4l2_fini(), both of which free the em28xx_v4l2 struct
and set dev->v4l2 to NULL under dev->lock.
This race leads to two issues:
- use-after-free in v4l2_fh_init() when accessing vdev->ctrl_handler,
since the video_device is embedded in the freed em28xx_v4l2 struct.
- NULL pointer dereference in em28xx_resolution_set() when accessing
v4l2->norm, since dev->v4l2 has been set to NULL.
Fix this by moving the mutex_lock() before the dev->v4l2 read and
adding a NULL check for dev->v4l2 under the lock. |
| In the Linux kernel, the following vulnerability has been resolved:
bcache: fix cached_dev.sb_bio use-after-free and crash
In our production environment, we have received multiple crash reports
regarding libceph, which have caught our attention:
```
[6888366.280350] Call Trace:
[6888366.280452] blk_update_request+0x14e/0x370
[6888366.280561] blk_mq_end_request+0x1a/0x130
[6888366.280671] rbd_img_handle_request+0x1a0/0x1b0 [rbd]
[6888366.280792] rbd_obj_handle_request+0x32/0x40 [rbd]
[6888366.280903] __complete_request+0x22/0x70 [libceph]
[6888366.281032] osd_dispatch+0x15e/0xb40 [libceph]
[6888366.281164] ? inet_recvmsg+0x5b/0xd0
[6888366.281272] ? ceph_tcp_recvmsg+0x6f/0xa0 [libceph]
[6888366.281405] ceph_con_process_message+0x79/0x140 [libceph]
[6888366.281534] ceph_con_v1_try_read+0x5d7/0xf30 [libceph]
[6888366.281661] ceph_con_workfn+0x329/0x680 [libceph]
```
After analyzing the coredump file, we found that the address of
dc->sb_bio has been freed. We know that cached_dev is only freed when it
is stopped.
Since sb_bio is a part of struct cached_dev, rather than an alloc every
time. If the device is stopped while writing to the superblock, the
released address will be accessed at endio.
This patch hopes to wait for sb_write to complete in cached_dev_free.
It should be noted that we analyzed the cause of the problem, then tell
all details to the QWEN and adopted the modifications it made. |
| In the Linux kernel, the following vulnerability has been resolved:
media: as102: fix to not free memory after the device is registered in as102_usb_probe()
In as102_usb driver, the following race condition occurs:
```
CPU0 CPU1
as102_usb_probe()
kzalloc(); // alloc as102_dev_t
....
usb_register_dev();
fd = sys_open("/path/to/dev"); // open as102 fd
....
usb_deregister_dev();
....
kfree(); // free as102_dev_t
....
sys_close(fd);
as102_release() // UAF!!
as102_usb_release()
kfree(); // DFB!!
```
When a USB character device registered with usb_register_dev() is later
unregistered (via usb_deregister_dev() or disconnect), the device node is
removed so new open() calls fail. However, file descriptors that are
already open do not go away immediately: they remain valid until the last
reference is dropped and the driver's .release() is invoked.
In as102, as102_usb_probe() calls usb_register_dev() and then, on an
error path, does usb_deregister_dev() and frees as102_dev_t right away.
If userspace raced a successful open() before the deregistration, that
open FD will later hit as102_release() --> as102_usb_release() and access
or free as102_dev_t again, occur a race to use-after-free and
double-free vuln.
The fix is to never kfree(as102_dev_t) directly once usb_register_dev()
has succeeded. After deregistration, defer freeing memory to .release().
In other words, let release() perform the last kfree when the final open
FD is closed. |
| In the Linux kernel, the following vulnerability has been resolved:
media: hackrf: fix to not free memory after the device is registered in hackrf_probe()
In hackrf driver, the following race condition occurs:
```
CPU0 CPU1
hackrf_probe()
kzalloc(); // alloc hackrf_dev
....
v4l2_device_register();
....
fd = sys_open("/path/to/dev"); // open hackrf fd
....
v4l2_device_unregister();
....
kfree(); // free hackrf_dev
....
sys_ioctl(fd, ...);
v4l2_ioctl();
video_is_registered() // UAF!!
....
sys_close(fd);
v4l2_release() // UAF!!
hackrf_video_release()
kfree(); // DFB!!
```
When a V4L2 or video device is unregistered, the device node is removed so
new open() calls are blocked.
However, file descriptors that are already open-and any in-flight I/O-do
not terminate immediately; they remain valid until the last reference is
dropped and the driver's release() is invoked.
Therefore, freeing device memory on the error path after hackrf_probe()
has registered dev it will lead to a race to use-after-free vuln, since
those already-open handles haven't been released yet.
And since release() free memory too, race to use-after-free and
double-free vuln occur.
To prevent this, if device is registered from probe(), it should be
modified to free memory only through release() rather than calling
kfree() directly. |
| In the Linux kernel, the following vulnerability has been resolved:
can: raw: fix ro->uniq use-after-free in raw_rcv()
raw_release() unregisters raw CAN receive filters via can_rx_unregister(),
but receiver deletion is deferred with call_rcu(). This leaves a window
where raw_rcv() may still be running in an RCU read-side critical section
after raw_release() frees ro->uniq, leading to a use-after-free of the
percpu uniq storage.
Move free_percpu(ro->uniq) out of raw_release() and into a raw-specific
socket destructor. can_rx_unregister() takes an extra reference to the
socket and only drops it from the RCU callback, so freeing uniq from
sk_destruct ensures the percpu area is not released until the relevant
callbacks have drained.
[mkl: applied manually] |
| In the Linux kernel, the following vulnerability has been resolved:
drm/imagination: Synchronize interrupts before suspending the GPU
The runtime PM suspend callback doesn't know whether the IRQ handler is
in progress on a different CPU core and doesn't wait for it to finish.
Depending on timing, the IRQ handler could be running while the GPU is
suspended, leading to kernel crashes when trying to access GPU
registers. See example signature below.
In a power off sequence initiated by the runtime PM suspend callback,
wait for any IRQ handlers in progress on other CPU cores to finish, by
calling synchronize_irq().
At the same time, remove the runtime PM resume/put calls in the threaded
IRQ handler. On top of not being the right approach to begin with, and
being at the wrong place as they should have wrapped all GPU register
accesses, the driver would hit a deadlock between synchronize_irq()
being called from a runtime PM suspend callback, holding the device
power lock, and the resume callback requiring the same.
Example crash signature on a TI AM68 SK platform:
[ 337.241218] SError Interrupt on CPU0, code 0x00000000bf000000 -- SError
[ 337.241239] CPU: 0 UID: 0 PID: 112 Comm: irq/234-gpu Tainted: G M 6.17.7-B2C-00005-g9c7bbe4ea16c #2 PREEMPT
[ 337.241246] Tainted: [M]=MACHINE_CHECK
[ 337.241249] Hardware name: Texas Instruments AM68 SK (DT)
[ 337.241252] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 337.241256] pc : pvr_riscv_irq_pending+0xc/0x24
[ 337.241277] lr : pvr_device_irq_thread_handler+0x64/0x310
[ 337.241282] sp : ffff800085b0bd30
[ 337.241284] x29: ffff800085b0bd50 x28: ffff0008070d9eab x27: ffff800083a5ce10
[ 337.241291] x26: ffff000806e48f80 x25: ffff0008070d9eac x24: 0000000000000000
[ 337.241296] x23: ffff0008068e9bf0 x22: ffff0008068e9bd0 x21: ffff800085b0bd30
[ 337.241301] x20: ffff0008070d9e00 x19: ffff0008068e9000 x18: 0000000000000001
[ 337.241305] x17: 637365645f656c70 x16: 0000000000000000 x15: ffff000b7df9ff40
[ 337.241310] x14: 0000a585fe3c0d0e x13: 000000999704f060 x12: 000000000002771a
[ 337.241314] x11: 00000000000000c0 x10: 0000000000000af0 x9 : ffff800085b0bd00
[ 337.241318] x8 : ffff0008071175d0 x7 : 000000000000b955 x6 : 0000000000000003
[ 337.241323] x5 : 0000000000000000 x4 : 0000000000000002 x3 : 0000000000000000
[ 337.241327] x2 : ffff800080e39d20 x1 : ffff800080e3fc48 x0 : 0000000000000000
[ 337.241333] Kernel panic - not syncing: Asynchronous SError Interrupt
[ 337.241337] CPU: 0 UID: 0 PID: 112 Comm: irq/234-gpu Tainted: G M 6.17.7-B2C-00005-g9c7bbe4ea16c #2 PREEMPT
[ 337.241342] Tainted: [M]=MACHINE_CHECK
[ 337.241343] Hardware name: Texas Instruments AM68 SK (DT)
[ 337.241345] Call trace:
[ 337.241348] show_stack+0x18/0x24 (C)
[ 337.241357] dump_stack_lvl+0x60/0x80
[ 337.241364] dump_stack+0x18/0x24
[ 337.241368] vpanic+0x124/0x2ec
[ 337.241373] abort+0x0/0x4
[ 337.241377] add_taint+0x0/0xbc
[ 337.241384] arm64_serror_panic+0x70/0x80
[ 337.241389] do_serror+0x3c/0x74
[ 337.241392] el1h_64_error_handler+0x30/0x48
[ 337.241400] el1h_64_error+0x6c/0x70
[ 337.241404] pvr_riscv_irq_pending+0xc/0x24 (P)
[ 337.241410] irq_thread_fn+0x2c/0xb0
[ 337.241416] irq_thread+0x170/0x334
[ 337.241421] kthread+0x12c/0x210
[ 337.241428] ret_from_fork+0x10/0x20
[ 337.241434] SMP: stopping secondary CPUs
[ 337.241451] Kernel Offset: disabled
[ 337.241453] CPU features: 0x040000,02002800,20002001,0400421b
[ 337.241456] Memory Limit: none
[ 337.457921] ---[ end Kernel panic - not syncing: Asynchronous SError Interrupt ]--- |
| In the Linux kernel, the following vulnerability has been resolved:
af_unix: Give up GC if MSG_PEEK intervened.
Igor Ushakov reported that GC purged the receive queue of
an alive socket due to a race with MSG_PEEK with a nice repro.
This is the exact same issue previously fixed by commit
cbcf01128d0a ("af_unix: fix garbage collect vs MSG_PEEK").
After GC was replaced with the current algorithm, the cited
commit removed the locking dance in unix_peek_fds() and
reintroduced the same issue.
The problem is that MSG_PEEK bumps a file refcount without
interacting with GC.
Consider an SCC containing sk-A and sk-B, where sk-A is
close()d but can be recv()ed via sk-B.
The bad thing happens if sk-A is recv()ed with MSG_PEEK from
sk-B and sk-B is close()d while GC is checking unix_vertex_dead()
for sk-A and sk-B.
GC thread User thread
--------- -----------
unix_vertex_dead(sk-A)
-> true <------.
\
`------ recv(sk-B, MSG_PEEK)
invalidate !! -> sk-A's file refcount : 1 -> 2
close(sk-B)
-> sk-B's file refcount : 2 -> 1
unix_vertex_dead(sk-B)
-> true
Initially, sk-A's file refcount is 1 by the inflight fd in sk-B
recvq. GC thinks sk-A is dead because the file refcount is the
same as the number of its inflight fds.
However, sk-A's file refcount is bumped silently by MSG_PEEK,
which invalidates the previous evaluation.
At this moment, sk-B's file refcount is 2; one by the open fd,
and one by the inflight fd in sk-A. The subsequent close()
releases one refcount by the former.
Finally, GC incorrectly concludes that both sk-A and sk-B are dead.
One option is to restore the locking dance in unix_peek_fds(),
but we can resolve this more elegantly thanks to the new algorithm.
The point is that the issue does not occur without the subsequent
close() and we actually do not need to synchronise MSG_PEEK with
the dead SCC detection.
When the issue occurs, close() and GC touch the same file refcount.
If GC sees the refcount being decremented by close(), it can just
give up garbage-collecting the SCC.
Therefore, we only need to signal the race during MSG_PEEK with
a proper memory barrier to make it visible to the GC.
Let's use seqcount_t to notify GC when MSG_PEEK occurs and let
it defer the SCC to the next run.
This way no locking is needed on the MSG_PEEK side, and we can
avoid imposing a penalty on every MSG_PEEK unnecessarily.
Note that we can retry within unix_scc_dead() if MSG_PEEK is
detected, but we do not do so to avoid hung task splat from
abusive MSG_PEEK calls. |
| In the Linux kernel, the following vulnerability has been resolved:
net: add proper RCU protection to /proc/net/ptype
Yin Fengwei reported an RCU stall in ptype_seq_show() and provided
a patch.
Real issue is that ptype_seq_next() and ptype_seq_show() violate
RCU rules.
ptype_seq_show() runs under rcu_read_lock(), and reads pt->dev
to get device name without any barrier.
At the same time, concurrent writers can remove a packet_type structure
(which is correctly freed after an RCU grace period) and clear pt->dev
without an RCU grace period.
Define ptype_iter_state to carry a dev pointer along seq_net_private:
struct ptype_iter_state {
struct seq_net_private p;
struct net_device *dev; // added in this patch
};
We need to record the device pointer in ptype_get_idx() and
ptype_seq_next() so that ptype_seq_show() is safe against
concurrent pt->dev changes.
We also need to add full RCU protection in ptype_seq_next().
(Missing READ_ONCE() when reading list.next values)
Many thanks to Dong Chenchen for providing a repro. |
| In the Linux kernel, the following vulnerability has been resolved:
dmaengine: mmp_pdma: Fix race condition in mmp_pdma_residue()
Add proper locking in mmp_pdma_residue() to prevent use-after-free when
accessing descriptor list and descriptor contents.
The race occurs when multiple threads call tx_status() while the tasklet
on another CPU is freeing completed descriptors:
CPU 0 CPU 1
----- -----
mmp_pdma_tx_status()
mmp_pdma_residue()
-> NO LOCK held
list_for_each_entry(sw, ..)
DMA interrupt
dma_do_tasklet()
-> spin_lock(&desc_lock)
list_move(sw->node, ...)
spin_unlock(&desc_lock)
| dma_pool_free(sw) <- FREED!
-> access sw->desc <- UAF!
This issue can be reproduced when running dmatest on the same channel with
multiple threads (threads_per_chan > 1).
Fix by protecting the chain_running list iteration and descriptor access
with the chan->desc_lock spinlock. |
