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CVE-2026-99249
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published on November 3, 2026
In the Linux kernel, the following vulnerability has been resolved:
pid_namespace: make zap_pid_ns_processes() freezable
When the init of a pid namespace exits, zap_pid_ns_processes() waits
until all other pids in the namespace are freed. A tracer outside the
namespace that does not reap its traced zombies keeps those pids
allocated, so this wait has no upper bound, and while it lasts every
suspend attempt fails:
Freezing user space processes failed after 20.006 seconds (2 tasks refusing to freeze, wq_busy=0):
Neither wait is freezable. The first loop sleeps in do_wait(), which
returns -ERESTARTSYS on the freezer's fake signal; the loop then clears
TIF_SIGPENDING and waits again without ever freezing. The final loop
sleeps in TASK_INTERRUPTIBLE, and since nothing clears TIF_SIGPENDING
there, schedule() returns immediately after the first freeze attempt
and the task spins until the wait ends.
Sleep in TASK_INTERRUPTIBLE | TASK_FREEZABLE in do_wait(), so that the
freezer can freeze tasks waiting there directly, and in TASK_IDLE |
TASK_FREEZABLE in the final loop, like coredump_task_exit() does.
This was hit with Chromium-based browsers: crashpad ptrace-attaches the
threads of a crashed renderer, which is a pid namespace init, and does
not reap those killed during the dump.
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CVE-2026-99248
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published on November 3, 2026
In the Linux kernel, the following vulnerability has been resolved:
i2c: xiic: restore non-managed runtime PM to fix clk WARN flood
The devres conversion replaced manual pm_runtime_enable()/disable() with
devm_pm_runtime_set_active_enabled() and dropped the remove-time runtime
PM teardown. The managed release tears runtime PM down in the wrong
order: it calls pm_runtime_dont_use_autosuspend() before
pm_runtime_disable(), i.e. while runtime PM is still enabled, and devres
is LIFO so the devm_clk_get_enabled() release runs afterwards.
At remove(), pm_runtime_put_sync() leaves the device active with the
autosuspend timer armed. Clearing use_autosuspend then makes rpm_idle()
suspend immediately, and xiic_i2c_runtime_suspend() clk_disable()s the
clock. The later devm_clk_get_enabled() release clk_disable_unprepare()s
the already-disabled clock, so clk_core_disable() WARNs ("clkN already
disabled") on every teardown.
Drop the managed helper and restore the non-managed runtime PM setup and
teardown, so runtime PM is enabled once in probe and disabled once in
remove and the clock enable count stays balanced.
Order the remove teardown so runtime PM is disabled before the usage
count is dropped: pm_runtime_disable() followed by pm_runtime_put_noidle()
instead of pm_runtime_put_sync(). Dropping the count first with autosuspend
still enabled arms the autosuspend timer, and a preemption before
pm_runtime_disable() lets it expire, suspend the device and clk_disable()
the clock, which the devm release then disables again - the same WARN.
Restore the non-managed IRQ request as well. The probe error paths now
unwind runtime PM by hand via goto, and a devm-registered handler is only
freed later during devres unwind, so it would stay live across the manual
teardown (and across any future failing step added after it). Request the
IRQ with request_threaded_irq() and free it explicitly in the probe error
path and in remove. The probe error path also clears use_autosuspend, to
match the teardown in remove().
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CVE-2026-99247
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published on November 3, 2026
In the Linux kernel, the following vulnerability has been resolved:
tracing: Do not initialize tracefs work if tracing is disabled
If trace buffer allocation fails during early boot (e.g. in
early_trace_init() - allocate_trace_buffers()), tracing_disabled is
left set to 1 and the global trace array events list remains
uninitialized.
Later during boot, tracer_init_tracefs() (invoked via fs_initcall)
queues tracerfs_init_work asynchronously without checking if tracing was
disabled. When tracer_init_tracefs_work_func() runs, it calls
event_trace_init() and init_tracer_tracefs(&global_trace, NULL)
unconditionally. This leads to __find_event_file() dereferencing an
uninitialized tr->events list, causing an early boot NULL pointer
dereference Oops:
BUG: Kernel NULL pointer dereference on read at 0x00000010
Faulting instruction address: 0xc000000000485be0
Oops: Kernel access of bad area, sig: 7 [#1]
...
NIP [c000000000485be0] __find_event_file+0x70/0x3c0
LR [c000000000448874] init_tracer_tracefs+0x274/0xc80
Call Trace:
init_tracer_tracefs+0x274/0xc80
tracer_init_tracefs_work_func+0x50/0x320
process_one_work+0x1e8/0x5c0
worker_thread+0x1dc/0x3d0
kthread+0x194/0x1b0
start_kernel_thread+0x14/0x18
Check tracing_disabled at the beginning of tracer_init_tracefs_work_func()
and return immediately if tracing is disabled or failed to initialize,
preventing the crash.
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CVE-2026-99246
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published on November 3, 2026
In the Linux kernel, the following vulnerability has been resolved:
tipc: protect node reset trace dump with node lock
The tipc_node_reset_links trace event asks tipc_node_dump() to walk the
node's link entries. Unlike the other node events that request link data,
this event runs without the node lock.
This permits bearer teardown to free a link while the trace callback is
dumping it:
CPU 0 CPU 1
trace_tipc_node_reset_links()
tipc_node_dump()
l = n-links[0].link
tipc_node_write_lock()
kfree(l)
n->links[0].link = NULL
tipc_node_write_unlock()
tipc_link_dump(l)
tipc_link_dump() then dereferences the stale pointer. KASAN reported:
BUG: KASAN: slab-use-after-free in tipc_link_dump
Read of size 4 by task poc/115
Call Trace:
tipc_link_dump+0x10cb/0x16b0
tipc_node_dump+0x4bb/0x740
trace_event_raw_event_tipc_node_class+0x258/0x360
tipc_node_reset_links+0x14d/0x1a0
tipc_rcv+0x13f5/0x3030
tipc_udp_recv+0x4e3/0x670
Allocated by task 0:
tipc_link_create+0x1e1/0x1020
tipc_node_check_dest+0x7d2/0x11a0
tipc_disc_rcv+0xdbf/0x1430
Freed by task 89:
kfree+0x131/0x3c0
tipc_node_link_down+0x267/0x4b0
tipc_node_delete_links+0xec/0x160
bearer_disable+0x107/0x260
Take the node write lock around the trace event. This serializes the
dump against tipc_node_link_down(delete=true), which frees the link
under the same write lock.
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CVE-2026-99245
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published on November 3, 2026
In the Linux kernel, the following vulnerability has been resolved:
KEYS: Fix key_reject_and_link() race with keyring restriction
The restrict_link check in key_reject_and_link() is done before taking
the keyring semaphore, racing with a concurrent keyring_restrict()
that installs the restriction while holding the semaphore in write
mode.
Move the check to after __key_link_lock(), so it is done under the
semaphore, matching the pattern used in __key_create_or_update().
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CVE-2026-99244
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published on November 3, 2026
In the Linux kernel, the following vulnerability has been resolved:
pid_namespace: prevent TIF_NOTIFY_SIGNAL from interrupting the reaper
Since commit 7fea700e04bd ("zap_pid_ns_processes: clear
TIF_NOTIFY_SIGNAL along with TIF_SIGPENDING") zap_pid_ns_processes()
clears TIF_NOTIFY_SIGNAL before every kernel_wait4() call. Otherwise
kernel_wait4() doesn't sleep and returns -ERESTARTSYS if
signal_pending() is true and the reaper busy-waits.
But clearing TIF_NOTIFY_SIGNAL doesn't fix it. It can get raised again.
For example, klp_send_signals() sets it raw against any task that hasn't
transitioned yet. And it keeps sending it until the livepatch finishes.
The sleep loop waiting for pid_allocated to drop has the same problem
and it doesn't even clear anything. So a schedule() in
TASK_INTERRUPTIBLE returns immediately.
Use a no_notify_signal guard. signal_pending() will ignore
TIF_NOTIFY_SIGNAL and the pid namespace reaper sleeps until a child
exits or free_pid() wakes it.
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CVE-2026-99242
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published on November 2, 2026
In the Linux kernel, the following vulnerability has been resolved:
ntfs: fix race between fallocate and mmap reads
The fallocate implementation only takes invalidate_lock for punch hole,
collapse range, and insert range operations. For standard allocation modes
(mode == 0, FALLOC_FL_KEEP_SIZE), the lock is not held.
During ntfs_attr_fallocate(), new clusters are mapped to the runlist via
ntfs_attr_map_cluster() before being zeroed by ntfs_dio_zero_range(). This
creates a window where concurrent mmap page faults can read uninitialized
disk data.
Since mmap uses filemap_fault() which takes invalidate_lock in shared mode,
it can fault in pages during this window and expose old disk contents to
userspace. This is an information leak and data integrity issue.
Fix by taking invalidate_lock for all fallocate operations, not just for
punch/collapse/insert modes. This prevents concurrent page faults from
accessing unzeroed clusters during the allocation window.
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CVE-2026-99241
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published on November 2, 2026
In the Linux kernel, the following vulnerability has been resolved:
ntfs: take invalidate_lock in ntfs_filemap_page_mkwrite()
ntfs_filemap_page_mkwrite() calls iomap_page_mkwrite() without holding
mapping-invalidate_lock, so a concurrent truncate or fallocate can be
in the middle of invalidating pagecache and rewriting the runlist while
the write fault maps blocks and dirties the folio. This races with
ntfs_attr_fallocate(), which merges clusters into the in-memory
runlist, drops the runlist lock, and only afterwards zeroes the newly
allocated clusters on disk; and with the punch-hole/insert/collapse
paths that free clusters after truncating the cache.
Per Documentation/filesystems/locking.rst, ->page_mkwrite() must ensure
there are no truncate/invalidate races, "usually mapping->invalidate_lock
is suitable for proper serialization". xfs takes its mmaplock (= the
invalidate_lock rwsem) shared in exactly this path.
Take invalidate_lock shared around iomap_page_mkwrite(). The read-only
fault path is already covered because filemap_fault() itself grabs
invalidate_lock shared on instantiation/read paths; only page_mkwrite
was bypassing it in this driver.
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CVE-2026-99240
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published on November 2, 2026
In the Linux kernel, the following vulnerability has been resolved:
mm/damon/core: error damos_commit_quota_goal() for zero target_value
Patch series "mm/damon: move zero damos quota target_value handling to the
core layer".
Having zero DAMOS quota target value can cause division by zero. DAMON
API callers are checking the target value parameters to avoid that. It is
easy to make mistakes in some of the multiple API callers. Move that to
the core layer.
Patch 1 adds the corner case handling into the core layer DAMON parameters
validation logic. Patches 2 and 3 remove no more needed DAMON API callers
side handling of the corner case in DAMON_LRU_SORT and DMON_SAMPLIE_MTIER,
respectively.
This patch (of 3):
If a DAMOS scheme has a damos_quota_goal of zero target_value,
damos_quota_goal() could trigger division-by-zero error. Hence each DAMON
API callers should do the zero target_value validation. It is easy to
make mistakes. Actually such bugs in DAMON_LRU_SORT and
DAMON_SAMPLE_MTIER were found and fixed [1].
It is better to handle the corner case only once in the core layer,
instead of multiple places in all DAMON API callers. One straightforward
option is using an alternative denominator for the corner case in the
damos_quota_goal(). However, the zero target_value is meaningless. In
this case, the quota goal is always evaluated as achieved or
over-achieved. The quota will only keep being reduced.
Simply avoid using zero target_value by adding a check in the core layer
DAMOS quota goal parameters validation/commit path,
damos_commit_quota_goal(). Update it to return an error in the case.
Also update its caller to propagate the error.
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CVE-2026-99239
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published on November 2, 2026
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: L2CAP: refuse __l2cap_chan_add if chan already has conn
l2cap_chan may be linked to l2cap_conn at most once. This is assumed in
several places, eg l2cap_chan_del cleanup.
There is a TOCTOU race where the invariant is violated:
[Task 1] [Task 2]
l2cap_chan_connect l2cap_sock_bind
l2cap_chan_lock lock_sock
l2cap_state_change if (sk-sk_state != BT_OPEN)
chan->state = BT_CONNECT
l2cap_sock_state_change_cb chan->state = BT_BOUND
sk->sk_state = BT_BOUND
lock_sock ------------------ release_sock
sk->sk_state = BT_CONNECT
l2cap_sock_connect() does not check sk->sk_state, so since chan->state
is now BT_BOUND, subsequent connect() ends up with second
__l2cap_chan_add.
Explicitly document and check the invariant in __l2cap_chan_add with
WARN_ON_ONCE. The only callsite where it could be hit is
l2cap_chan_connect, so add pre-check there to avoid relying on
chan->state. chan->state read/write is not properly guarded currently so
there can be other TOCTOUC problems.
Add l2cap_lock_chan in l2cap_sock_bind() to guard chan->state write.
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CVE-2026-99238
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published on November 2, 2026
In the Linux kernel, the following vulnerability has been resolved:
tracing: Hold trace_types_lock when updating modules in persistent instances
trace_module_record() walks ftrace_trace_arrays from the module notifier
without trace_types_lock. A concurrent rmdir of an instance removes it
from the list and frees it under that lock, so a module load or unload
can walk into a freed trace_array.
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CVE-2026-99237
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published on November 2, 2026
In the Linux kernel, the following vulnerability has been resolved:
tracing: Hold trace_types_lock when resetting last boot data from readers
update_last_data_if_empty() is called from tracing_open() with O_TRUNC,
tracing_read_pipe() and tracing_buffers_read() without trace_types_lock.
Two readers can both pass the LAST_BOOT test and free module_delta
twice, and a module notifier can update module_delta while it is being
freed.
Take trace_types_lock in those paths and keep the callers that already
hold it on an unlocked variant.
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CVE-2026-99236
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published on November 2, 2026
In the Linux kernel, the following vulnerability has been resolved:
tracing: Reject incomplete event filter expressions
A non-empty expression normally finishes in predicate_parse()'s inner
loop, which resolves the pending logical operators before jumping to
finalization. If the input ends after an operator, possibly followed by
unary '!' tokens, the outer loop instead falls through with unresolved
operator state.
For example, "common_pid == 1 || common_pid == 2 &&" leaves
prog[0].target equal to -1. The second pass then reads prog[-1] before
the forward-jump check can reject it. Depending on adjacent slab
contents, it can also copy an out-of-bounds word into a branch target
that passes the forward-only check. A self-targeted perf tracepoint
counting event can reach this path through PERF_EVENT_IOC_SET_FILTER.
Reject the outer-loop fallthrough when a predicate has already been
parsed. This ensures that non-empty expressions only reach finalization
after the inner loop has resolved their operators. Keep the existing
no-filter error for input that has no predicates. Add a regression test
for trailing logical operators and unary negations.
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CVE-2026-99235
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published on November 2, 2026
In the Linux kernel, the following vulnerability has been resolved:
tracing: Save the event file instead of the compatible histogram
create_field_var_hist() creates a histogram on the matched event to
supply a field variable, and records it on the target so it can be torn
down later:
hist_data = find_compatible_hist(target_hist_data, file);
...
/* Save the compatible histogram information */
var_hist-hist_data = hist_data;
hist_data is not the histogram it creates. It is one that was already
there, whose keys the new one copies. The saved pointer has a single
user, unregister_field_var_hists(), which runs when the target is
removed:
file = hist_data->field_var_hists[i]->hist_data->event_file;
find_compatible_hist() matches on keys alone, so it can pick one with no
variables of its own. check_var_refs() then returns false and the user
can remove it while the target still points at it:
BUG: KASAN: slab-use-after-free in event_hist_trigger_free+0x2b2/0x320
Read of size 8 at addr ffff8880093b90e0 by task init/1
Freed by task 1:
kfree+0x154/0x420
event_hist_trigger_free+0x1d5/0x320
event_hist_trigger_parse+0x35f3/0x69e0
trigger_process_regex+0x1a6/0x250
Save the event file instead. It is all the dereference ever wanted, and
it does not go away when the user removes a trigger.
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CVE-2026-99234
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published on November 2, 2026
In the Linux kernel, the following vulnerability has been resolved:
tracing: Unregister field variable histograms when the command fails
An action that names a field on another event needs that field as a
variable, so create_field_var_hist() registers a second hist trigger on
that event to provide it, and records it in
target_hist_data-field_var_hists[].
If a later part of the same command fails, create_actions() returns an
error and event_hist_trigger_parse() jumps to out_free. The write fails
with -EINVAL and sched_switch gets no trigger, but:
# echo 'hist:keys=pid:ts0=common_timestamp.usecs' >> \
events/sched/sched_waking/trigger
# echo 'my_synth u64 lat; int a; int b' >> synthetic_events
# echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0:\
onmatch(sched.sched_waking).my_synth($wakeup_lat,prio,nosuchfld)'\
>> events/sched/sched_switch/trigger
# cat events/sched/sched_waking/trigger
hist:keys=pid:vals=hitcount:ts0=common_timestamp.usecs:sort=hitcount:size=2048:clock=global [active]
hist:keys=pid:vals=hitcount:synthetic_prio=prio:sort=hitcount:size=2048 [active]
The second histogram is the one created for 'prio'. It is still active and
still counting.
out_free reaches destroy_field_var_hists(), which frees the
field_var_hists[] entries, but never unregister_field_var_hists(), which is
what removes the triggers and runs only from event_hist_trigger_free(). The
entry is freed and the trigger is left with nothing tracking it.
Unregister the field variable histograms in out_free as well, and record
each one as soon as its trigger is registered rather than after the lookup
that follows it, so no exit can leave a registered trigger untracked. The
entry then belongs to field_var_hists[] and is released by
destroy_field_var_hists(), so freeing it on that exit would be a double
free.
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CVE-2026-99233
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published on November 2, 2026
In the Linux kernel, the following vulnerability has been resolved:
tracing/histograms: Verify event_call identity when updating synth_event refcount
In event_hist_trigger_parse() and hist_unreg_all(), the histogram
registration and unregistration paths look up find_synth_event() using
trace_event_name(file-event_call) and adjust se->ref if a match is
found.
Because find_synth_event() only compares the event basename, registering
or removing a histogram on a non-synthetic trace event whose basename
matches a synthetic event erroneously modifies the synthetic event's
reference count. If a histogram is registered on the non-synthetic
event before the synthetic event is created and removed afterwards,
se->ref is decremented without a matching increment, allowing the
synthetic event to be freed while an active histogram action still holds
a pointer to it.
Introduce find_synth_event_call() to verify that &se->call matches
file->event_call before adjusting se->ref.
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CVE-2026-99232
•
published on November 2, 2026
In the Linux kernel, the following vulnerability has been resolved:
tracing/syscalls: Use copy_from_user for the faultable syscall buffer
syscall_copy_user_array() copies the buffer argument of faultable
syscalls (write, pwrite64, ...) with __copy_from_user(), which skips
access_ok(). Use copy_from_user() instead so a non-user address is
rejected and the entry is recorded as faulted.
It could be a security concern for machines that trust perf a bit too
much.
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CVE-2026-99231
•
published on November 2, 2026
In the Linux kernel, the following vulnerability has been resolved:
io_uring/waitid: own the request before clearing -head
io_waitid_remove_wq() only takes the wait queue lock if ->head is set.
io_waitid_wait() clears ->head first thing, before it tries to become the
owner of the request by bumping ->refs. If somebody else owns the request
at that point, nothing keeps it from completing the request while the
wake up handler is still going to touch it:
CPU0 (io_waitid_wait) CPU1 (io_waitid, holds a ref)
list_del_init(&wait->entry)
smp_store_release(&iw->head, NULL)
__do_wait() finds another child
io_waitid_remove_wq()
// ->head == NULL, no locking
io_waitid_finish(), IOU_COMPLETE
// request freed and reused
atomic_fetch_inc(&iw->refs)
The same goes for __io_waitid_cancel() if it claims the request in that
window. ->refs is part of the per opcode data of the request, so this
increments whatever the next user of the request keeps there. If that
happens to be zero, the handler concludes that it owns the request, and
queues io_waitid_cb() for it. With the window held open by a delay, and
the request reused for a receive that is waiting for data:
BUG: KASAN: slab-use-after-free in __wake_up_common+0x1ca/0x1f0
__wake_up_sync_key+0x36/0x50
sock_def_readable+0xf1/0x420
unix_stream_sendmsg+0x60b/0x1110
Allocated by task 87:
io_arm_apoll+0x1ed/0x940
Freed by task 87:
__io_submit_flush_completions+0x118d/0x1a10
tctx_task_work_run+0x327/0x950
Only clear ->head once the handler owns the request. If it doesn't, the
owner finds ->head set and has to wait for the lock, which is held by the
caller of the handler. Deleting the already deleted entry again is
harmless.
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CVE-2026-99230
•
published on November 2, 2026
In the Linux kernel, the following vulnerability has been resolved:
io_uring/cmd: don't leave list poison in -hash_node
io_uring_cmd_del_cancelable() uses hlist_del() to take a command off
->cancelable_uring_cmd, which leaves LIST_POISON1/2 behind in
->hash_node. Requests are recycled through the request cache without
being reinitialised, and not every user of ->hash_node sets it up before
it is used:
If a vectored futex wait is woken while futex_wait_multiple_setup() is
still queueing the futexes, io_futexv_wait() doesn't add the request to
->futex_list, and leaves the completion to the task_work queued by the
wake up. io_futexv_complete() ends in __io_futex_complete(), whose
hlist_del_init() is fine for a request that is unhashed, which is how all
other users of the node leave it. If the request was a cancelable
uring_cmd in its previous life, e.g. a ublk FETCH_REQ, it writes through
LIST_POISON2:
Oops: general protection fault, probably for non-canonical address
KASAN: maybe wild-memory-access in range [0xdead000000000120-...]
RIP: 0010:io_futexv_complete+0x219/0x420
Call Trace:
tctx_task_work_run+0x804/0x950
tctx_task_work+0x71/0xa0
task_work_run+0x118/0x200
Leave the node unhashed.
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CVE-2026-99229
•
published on November 2, 2026
In the Linux kernel, the following vulnerability has been resolved:
io_uring/wait: don't spin on a stuck overflow list
As long as IO_CHECK_CQ_OVERFLOW_BIT is set, io_cqring_wait_schedule()
returns right away, before it gets to look at signals or arms the timeout,
for io_cqring_wait() to flush the overflow list. If that doesn't empty the
list, and the CQ ring doesn't hold the number of events the caller wants,
the loop starts over, with the same result. The task spins in the kernel,
and can't be killed.
The assumption is that this can't happen: if CQEs can't be flushed, the
ring is full, and min_events is capped to the size of the ring. But:
- With IORING_SETUP_CQE_MIXED a 32b CQE needs two contiguous entries. It
is stuck on the list if a single one is free, and then the ring holds
less than cq_entries events. A single threaded application that asks
for as many events as the ring has entries never gets out of
io_uring_enter().
- Whether the ring is full is up to the CQ head, which the application
can write to. While one thread waits for events on an empty ring,
another one can move the head back so that the ring looks full and
have a CQE overflow. The waiter can't be stopped any more, not even by
SIGKILL.
Only the application can make room in the CQ ring. Return to it if the
list could not be flushed.