🚨 CVE-2026-97917
In the Linux kernel, the following vulnerability has been resolved:

accel/ivpu: Validate full buffer range in ivpu_to_cpu_addr

Add a size parameter to ivpu_to_cpu_addr() and validate that the
whole [vpu_addr, vpu_addr + size) range stays within the BO.

🎖@cveNotify

🚨 CVE-2026-97918
In the Linux kernel, the following vulnerability has been resolved:

tracing: Undo the registration when enabling the histogram trigger fails

Commit 6f86bdeab633 ("tracing: Fix bad hist from corrupting named_triggers
list") described how a trigger that is registered but not on file->triggers
ends up freed while still on the global named_triggers list, and moved the
registration down so that hist_trigger_enable() follows it immediately. One
path still gets there. hist_trigger_enable() adds the trigger and takes it
straight back out when the event cannot be enabled:

list_add_tail_rcu(&data->list, &file->triggers);

update_cond_flag(file);

if (trace_event_trigger_enable_disable(file, 1) < 0) {
list_del_rcu(&data->list);
update_cond_flag(file);
ret--;
}

so the list walk in hist_unregister_trigger() matches nothing, test stays
NULL, and the ->free() that would call del_named_trigger() is skipped.
out_unreg falls through to out_free, which frees the trigger anyway:

BUG: KASAN: slab-use-after-free in find_named_trigger+0xac/0xc0
Read of size 8 at addr ffff8880091d3160 by task init/1
find_named_trigger+0xac/0xc0
hist_register_trigger+0xc1/0xa00
event_hist_trigger_parse+0x3146/0x6af0
event_trigger_write+0xce/0x160
Freed by task 69:
kfree+0x154/0x420
trigger_kthread_fn+0xfd/0x160

Leave the trigger where hist_unregister_trigger() can find it and let that
undo the registration, which is the only code that knows all of what
cmd_ops->init() took: the named list entry, the hist_pad reference, the
reference on the trigger a named histogram is shared with, and the copied
cmd_ops. It also pairs the failed trace_event_trigger_enable_disable(),
whose sm_ref and buffered event reference are otherwise left behind.

Since ->free() releases trigger_data and, for a trigger that does not share
its histogram, hist_data with it, out_unreg can no longer fall through to
out_free. For a trigger that does share, hist_register_trigger() has
already destroyed the caller's hist_data, so the fall-through was reading
freed memory there as well.

Move the enable_timestamps check in hist_unregister_trigger() above the
->free() call for the same reason: hist_data does not outlive it once the
trigger being removed is the one that owns it.

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🚨 CVE-2026-97919
In the Linux kernel, the following vulnerability has been resolved:

tracing: Take the reference before publishing the named histogram trigger

event_hist_trigger_named_init() puts the trigger on the global
named_triggers list and only then takes the reference on the trigger it
shares its histogram with:

data->ref++;

save_named_trigger(data->named_data->name, data);

ret = event_hist_trigger_init(data->named_data);
if (ret < 0) {
kfree(data->cmd_ops);
data->cmd_ops = &trigger_hist_cmd;
}

return ret;

event_hist_trigger_init() fails when alloc_hist_pad() cannot allocate, and
nothing takes the trigger back off the list on the way out.
event_hist_trigger_parse() frees it, and the next lookup by name reads the
freed object:

BUG: KASAN: slab-use-after-free in find_named_trigger+0xac/0xc0
Read of size 8 at addr ffff888009346860 by task init/1
find_named_trigger+0xac/0xc0
hist_register_trigger+0xc1/0xa00
event_hist_trigger_parse+0x3146/0x6af0
event_trigger_write+0xce/0x160
Freed by task 67:
kfree+0x154/0x420
trigger_kthread_fn+0xfd/0x160

Do the reference first and publish once it has succeeded, so that nothing
which can fail runs after the trigger becomes findable.

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🚨 CVE-2026-97920
In the Linux kernel, the following vulnerability has been resolved:

tracing: Keep the entry count when the histogram stats allocation fails

print_entries() uses n_entries both as the number of sort entries and as
its own return value, so the -ENOMEM it stores when the stats allocation
fails overwrites the count that the cleanup still needs:

n_entries = tracing_map_sort_entries(map, ...);
if (n_entries < 0)
return n_entries;
...
if (!stats) {
n_entries = -ENOMEM;
goto out;
}
...
out:
tracing_map_destroy_sort_entries(sort_entries, n_entries);

tracing_map_destroy_sort_entries() takes an unsigned int and loops up to
it, so -ENOMEM arrives as 4294967284. It walks an array of at most
map->max_elts pointers and calls destroy_sort_entry(), which dereferences
and frees, on whatever lies past the end.

Reading the hist file of a trigger with a .percent value, with that
allocation forced to fail:

BUG: KASAN: vmalloc-out-of-bounds in tracing_map_destroy_sort_entries+0xa0/0xb0
Read of size 8 at addr ffffc90000045000 by task init/1
tracing_map_destroy_sort_entries+0xa0/0xb0
hist_show+0x6f7/0x1df0
seq_read_iter+0x2b8/0x1190
vfs_read+0x176/0xa40
The buggy address belongs to a 4-page vmalloc region starting at
ffffc90000041000 allocated at tracing_map_sort_entries+0x5c/0xd50

A few pages further the fault is fatal. The registers at the oops confirm
the bound: the loop's end pointer less the array start, over the pointer
size, is 4294967284.

Return the error in a separate variable and leave n_entries holding the
count, the way tracing_map_sort_entries() does on its own error path.

The stats block is only entered for a value carrying .percent or .graph,
which __create_val_field() has rejected since v6.3, so this cannot be
reached in mainline as it stands. It becomes reachable again with
"tracing: hist: let values keep the percent and graph modifiers", so it
should be applied first.

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🚨 CVE-2026-97921
In the Linux kernel, the following vulnerability has been resolved:

tracing: Free histogram the field rejected for a bad modifier

Writing a hist trigger whose value or variable carries a modifier that is
not allowed there leaks the fields that were built for it.

__create_val_field() takes the field from parse_expr() and stores it in
hist_data->fields[] only after the modifier checks have run:

hist_field = parse_expr(hist_data, file, field_str, flags, var_name,
&n_subexprs);
...
if (hist_field->flags & HIST_FIELD_FL_VAR) {
if (hist_field->flags & (...))
goto err;
} else {
if (hist_field->flags & (...))
goto err;
}

hist_data->fields[val_idx] = hist_field;

Both checks jump past that store, and the err label returns without
freeing anything. The error unwinds to create_hist_data(), which calls
destroy_hist_data() -> destroy_hist_fields(), and that reaches a field
only by walking fields[]. A field that never got there is unreachable.

commit e0213434fe3e ("tracing: Do not let histogram values have some
modifiers") set ret to -EINVAL and fell through to the store, which left
the field owned by fields[] and freed along with the rest of hist_data.
Splitting the check into a value case and a variable case replaced that
fall-through with a goto that skips it.

With CONFIG_DEBUG_KMEMLEAK, 200 writes of

# echo 'hist:keys=prev_pid:vals=next_pid.log2' > \
events/sched/sched_switch/trigger

each correctly rejected with -EINVAL, leave 332 unreferenced objects
(63744 bytes) reported at create_hist_field(); 200 install and remove
cycles of a valid trigger leave none. A '.log2' field is two
allocations, since create_hist_field() puts the plain field in
operands[0] of the log2 field, and both are reported.

Use destroy_hist_field() rather than __destroy_hist_field() so that
operands[0] is freed as well. It returns early for HIST_FIELD_FL_VAR_REF,
which is what an operand owned by hist_data->var_refs[] needs; the
rejected field itself is never a var ref, because a var ref never carries
a modifier flag.

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🚨 CVE-2026-97922
In the Linux kernel, the following vulnerability has been resolved:

tracing: Free histogram var refs regardless of how often they are referenced

Using the same variable three or more times in one hist trigger leaks the
variable reference and its strings when the trigger is removed.

commit 656fe2ba85e8 ("tracing: Use hist trigger's var_ref array to destroy
var_refs") made a trigger's var_refs[] array the only owner of a var ref:
destroy_hist_field() returns early for HIST_FIELD_FL_VAR_REF, so the field
expressions never destroy one. One entry, freed once, no count needed.

commit 8bcebc77e85f ("tracing: Fix histogram code when expression has same
var as value") then made repeated references share one object and added a
count of them. Only the increment side exists, since those expressions
still return early and never drop a reference, so __destroy_hist_field()
sees how many references were created rather than how many are left. It
frees when the decremented count is 0 or 1, so two references work and
three or more leak.

Sharing kept one array entry per object, and create_var_ref() searches and
appends within a single trigger, so nothing outside it holds the object.
Removing a trigger whose variables are still referenced is already refused
by check_var_refs() with -EBUSY. Drop the count and free unconditionally.

🎖@cveNotify

🚨 CVE-2026-97923
In the Linux kernel, the following vulnerability has been resolved:

tracing: Free histogram the var ref when its initialization fails

create_var_ref() allocates a VAR_REF hist_field and then calls
init_var_ref() to fill it in. When that fails the field is leaked.

commit 656fe2ba85e8 ("tracing: Use hist trigger's var_ref array to destroy
var_refs") made destroy_hist_field() return early for
HIST_FIELD_FL_VAR_REF, since var refs are freed by walking the trigger's
var_refs[] array instead. create_var_ref() adds the field to that array
only after init_var_ref() has succeeded, so on this path the field is in
neither place and nothing frees it. The call was correct when it was
written, before var refs were taken out of destroy_hist_field().

init_var_ref() cannot free it either. The caller owns the field, so
init_var_ref() undoes only its own string allocations and leaves the
field alone. Freeing it there would leave create_var_ref() passing freed
memory to destroy_hist_field(), which reads its flags.

Call __destroy_hist_field(), which frees the field without consulting
the flag.

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🚨 CVE-2026-97924
In the Linux kernel, the following vulnerability has been resolved:

tracing/user_events: Don't destroy fields when event removal fails

destroy_user_event() destroys the event's fields before attempting to
remove the trace event call. If user_event_set_call_visible() fails,
e.g. because the event is still enabled and trace_remove_event_call()
returns -EBUSY, the event is left registered with an irreversibly
destroyed field list. Any subsequent interaction with the event then
operates on an empty field list while it is still fully visible in
tracefs.

Move the field destruction after the call removal, and splice the
field list back onto the event when the removal fails so the event
remains in a consistent state.

🎖@cveNotify

🚨 CVE-2026-97925
In the Linux kernel, the following vulnerability has been resolved:

tick/broadcast: Plug clockevents replacement race

朱恺乾 reported and decoded the following race condition when a broadcast
device is replaced:

CPUA CPUB
__tick_broadcast_oneshot_control()
bc = tick_broadcast_device.evtdev;
tick_install_broadcast_device(dev)
clockevents_exchange_device(cur, dev)
shutdown(cur);
detach(cur);
cur->handler = noop;
tick_broadcast_device.evtdev = dev;

tick_broadcast_set_event(bc, next_event); <- FAIL: arms a detached device.

If the original broadcast device has a restricted interrupt affinity mask
and the last CPU in that mask goes offline then the BUG() in
tick_cleanup_dead_cpu() triggers because the clockevent device is not in
detached state.

The reason for this is that tick_install_broadcast_device() is not
serialized vs. tick broadcast operations.

The obvious cure is to serialize tick_install_broadcast_device() with
tick_broadcast_lock against a concurrent tick broadcast operation.

That requires to split clockevents_exchange_device() into two parts, one
which does the exchange, shutdown and detach operation and the other which
drops the module reference count. This is required because the module
reference cannot be dropped while holding tick_broadcast_lock.

Let clockevents_exchange_device() do both operations as before, but let the
broadcast device code take the two step approach and do the device
exchange under tick_broadcast_lock and drop the module reference count
after releasing it.

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🚨 CVE-2026-97926
In the Linux kernel, the following vulnerability has been resolved:

ufs: validate cylinder group metadata before caching it

ufs_read_cylinder() copies the cylinder group index and the rotor
positions straight from the on-disk group and caches them without any
check:

ucpi->c_cgx = fs32_to_cpu(sb, ucg->cg_cgx);
ucpi->c_rotor = fs32_to_cpu(sb, ucg->cg_rotor);
ucpi->c_frotor = fs32_to_cpu(sb, ucg->cg_frotor);
ucpi->c_irotor = fs32_to_cpu(sb, ucg->cg_irotor);

They are then used as indices during allocation and free:

- c_cgx indexes the cylinder summary array as
UFS_SB(sb)->fs_cs(ucpi->c_cgx), so a value past s_ncg writes a 32
bit count outside the s_csp allocation.

- c_frotor becomes a bitmap scan start, start = c_frotor >> 3, and
then length = ((s_fpg + 7) >> 3) - start. A start beyond the block
bitmap wraps the unsigned length to a huge value, so ubh_scanc()
walks far past the cylinder group buffers. c_irotor drives the
inode bitmap the same way.

A crafted image can set any of these freely, turning an ordinary
allocation into an out of bounds access.

Reject a cylinder group whose recorded index does not match the group
being read, or whose rotors fall outside the group, before the metadata
is cached. Valid filesystems keep cg_cgx equal to the group number and
the rotors within the group, so only malformed images are rejected.

🎖@cveNotify

🚨 CVE-2026-97927
In the Linux kernel, the following vulnerability has been resolved:

ufs: create the root dentry after loading cylinder metadata

ufs_fill_super() installed sb->s_root before it loaded the cylinder
group structures for a writable mount:

sb->s_root = d_make_root(inode);
...
if (!sb_rdonly(sb))
if (!ufs_read_cylinder_structures(sb))
goto failed;

When ufs_read_cylinder_structures() failed, the error path freed the
in-core superblock information and set sb->s_fs_info to NULL while
sb->s_root stayed installed. get_tree_bdev() then reached
deactivate_locked_super(), and because s_root was present,
generic_shutdown_super() called sync_filesystem() and the put_super
operation. Both dereference UFS_SB(sb), which is now NULL, so a mount
that fails only while reading the cylinder groups oopses during
teardown. A crafted image whose first cylinder group cannot be read
reaches this path.

Load the cylinder group metadata first and create the root dentry last,
so the superblock is published to the VFS only once it is fully set up.
ufs_setup_cstotal() and ufs_read_cylinder_structures() take only the
super_block and do not use the root inode, so the reordering is safe.

🎖@cveNotify

🚨 CVE-2026-97928
In the Linux kernel, the following vulnerability has been resolved:

drm/amdgpu: skip the VMID 0 flush for VRAM

Clear-on-release only runs on VRAM, which amdgpu_ttm_map_buffer() reaches
via its direct MC address without programming a GART window, yet the wipe
still forces a VMID 0 flush. On GFX11 (e.g. Navi33) that spurious SDMA
flush can wedge the engine; only flush when a GART window is actually used.

v2: Let amdgpu_ttm_map_buffer() return whether the VMID 0 flush is needed,
and drive the clear and copy paths from that. (Christian)
v3: Make the vm_needs_flush output parameter mandatory instead of
allowing NULL. (Christian)

(cherry picked from commit a306e406e570b74318ff7d80e5b07b540ca1d3a9)

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🚨 CVE-2026-97929
In the Linux kernel, the following vulnerability has been resolved:

ALSA: usbusx2y: validate URB actual_length in interrupt callback

i_usx2y_in04_int() processes the interrupt URB data without checking
urb->actual_length. A short transfer from a malfunctioning device
would cause the handler to process uninitialized heap data from the
kmalloc-allocated in04_buf, which is then copied to the mmap-accessible
ctl_snapshot[] array.

Fix by using kzalloc() for in04_buf to zero-initialize the buffer,
and adding an actual_length check to skip processing on short
transfers while still resubmitting the URB.

🎖@cveNotify

🚨 CVE-2026-97930
In the Linux kernel, the following vulnerability has been resolved:

ALSA: usbusx2y: fix in04_last array size mismatch with in04_buf

The in04_last array in struct usx2ydev is declared as char[24], but
in04_buf is allocated as sizeof(struct us428_ctls) which is 21 bytes.
In i_usx2y_in04_int(), when ctl_snapshot_last == -2 (initialization
path):

memcpy(usx2y->in04_last, usx2y->in04_buf, sizeof(usx2y->in04_last));

This copies 24 bytes from a 21-byte slab allocation, reading 3 bytes
past the end of the source object.

Introduce a USX2Y_IN04_SIZE constant defined as sizeof(struct
us428_ctls) and use it consistently for the in04_last array, the
in04_buf allocation, the URB transfer length, and the comparison loop,
replacing the bare 24 and 21 literals throughout.

🎖@cveNotify

🚨 CVE-2026-97931
In the Linux kernel, the following vulnerability has been resolved:

ALSA: us122l: Prevent write upgrades for read mappings

The hwdep mmap callback rejects read-buffer mappings that are initially
writable, but leaves VM_MAYWRITE set on mappings created with PROT_READ.
A process that can open the hwdep node O_RDWR can later use mprotect() to
make the mapping writable.

The read allocation begins with struct usb_stream. Its read_size member is
used by the fault handler to decide which pages belong to the read buffer.
The read VMA intentionally remains expandable because pcm_usb_stream uses
mremap() after reading that size. Changing read_size first can therefore
map and access pages beyond the allocation. The same member is also
consumed by usb_stream_free(), where changing it can make
free_pages_exact() release pages outside the allocation.

Clear VM_MAYWRITE for read-buffer mappings after rejecting an initially
writable VMA. This keeps the separate output-buffer mapping writable while
preventing later permission upgrades.

🎖@cveNotify

🚨 CVE-2026-97932
In the Linux kernel, the following vulnerability has been resolved:

tracing: Don't dereference trace_event_file in deferred trigger free

The enable_event trigger defers trace_event_put_ref() to the
trigger free kthread, but the trace_event_file can already be freed
when the instance is removed.

Keep the trace_event_call directly in enable_trigger_data so the
deferred free does not access the freed trace_event_file.

🎖@cveNotify

🚨 CVE-2026-97934
In the Linux kernel, the following vulnerability has been resolved:

tracing: Fix memory corruption from a "STACKTRACE" histogram key

"cpu", "CPU", "stacktrace" and "STACKTRACE" are generic fields, defined
with an offset and a size of zero so that the filter code can match them
by name. parse_field() maps them onto their common_* equivalents for
backward compatibility, but unlike the common_* names it hands the
placeholder back to the caller instead of NULL.

create_hist_field() takes a non-NULL field as a promise that the record
carries a stacktrace and picks HIST_FIELD_FN_STACK, so the __data_loc
word is read from offset 0, that is from common_type, and its low 16
bits are followed as an offset into the record. What is found there
becomes the length of an unbounded memcpy. Pick an event whose id is
small enough that the offset stays inside its own record and the length
is a kernel text address:

# cd /sys/kernel/tracing
# echo 'hist:keys=STACKTRACE' > events/ftrace/print/trigger
# echo hello > trace_marker

Oops: general protection fault, probably for non-canonical address
RIP: 0010:rb_next+0x23/0x60
</IRQ>
RIP: 0010:memcpy+0xc/0x30
event_hist_trigger+0x2e7/0x12c0
Kernel panic - not syncing: Fatal exception in interrupt

Leave the field NULL, which is what the comment above the branch says
the code does and what common_stacktrace already does. FILTER_CPU and
FILTER_COMM are left alone, their create_hist_field() branches never
look at the field.

🎖@cveNotify

🚨 CVE-2026-97935
In the Linux kernel, the following vulnerability has been resolved:

tracing: Set the trace clock before registering the histogram trigger

hist_register_trigger() puts the trigger on the global named_triggers
list in cmd_ops->init(), and only then sets the trace clock:

if (data->cmd_ops->init) {
ret = data->cmd_ops->init(data);
if (ret < 0)
goto out;
}

if (hist_data->enable_timestamps) {
ret = tracing_set_clock(file->tr, hist_data->attrs->clock);
if (ret) {
hist_err(tr, HIST_ERR_SET_CLOCK_FAIL, errpos(clock));
goto out;
}

The clock string is not checked anywhere before that call, so a named
trigger using common_timestamp with an unknown clock fails after it has
already become findable. event_hist_trigger_parse() then frees it
without taking it off the list, and the next lookup by name reads the
freed object:

~# cd /sys/kernel/tracing/events/sched/sched_switch
~# echo 'hist:name=foo:keys=common_pid:ts=common_timestamp:clock=bogus' > trigger
bash: echo: write error: Invalid argument
~# echo 'hist:name=foo:keys=common_pid' > trigger

BUG: KASAN: slab-use-after-free in find_named_trigger+0xac/0xc0
Read of size 8 at addr ffff88800915d760 by task init/1
find_named_trigger+0xac/0xc0
hist_register_trigger+0xc1/0x900
event_hist_trigger_parse+0x3146/0x6af0
event_trigger_write+0xce/0x160
Freed by task 63:
kfree+0x154/0x420
trigger_kthread_fn+0xfd/0x160

Set the clock before the trigger is registered, so that nothing which
can fail runs after it is published, the way commit 6f86bdeab633
("tracing: Fix bad hist from corrupting named_triggers list") moved the
registration below the rest of the setup.

tracing_set_filter_buffering() is reference counted, so the init failure
path has to drop the reference that the clock block now takes first.

🎖@cveNotify

🚨 CVE-2026-97936
In the Linux kernel, the following vulnerability has been resolved:

tracing: Fix memory corruption from the histogram stacktrace modifier

parse_field() sets HIST_FIELD_FL_STACKTRACE from the ".stacktrace"
modifier before it looks the field name up, and nothing afterwards
checks that the name resolved to a field which holds a stacktrace.
create_hist_field() picks HIST_FIELD_FN_STACK on the strength of the
field pointer alone, which reads a __data_loc word from the record and
follows its low 16 bits as an offset into the same record.
event_hist_trigger() takes the first word there as an entry count and
copies that many longs into a 31 entry array:

n_entries = *stack;
memcpy(entries, ++stack, n_entries * sizeof(unsigned long));

Neither end of that copy is bounded, and the count is whatever the event
holds at the offset, so any field will do:

# cd /sys/kernel/tracing/events/sched/sched_process_fork
# echo 'hist:keys=parent_pid.stacktrace' > trigger
# (true)

BUG: kernel NULL pointer dereference, address: 0000000000000008
RIP: 0010:rb_insert_color+0x18/0x130
timerqueue_linked_add+0x7e/0xd0
enqueue_hrtimer+0x39/0xb0
__hrtimer_run_queues+0x10f/0x1f0
</IRQ>
RIP: 0010:memcpy+0xc/0x30
event_hist_trigger+0x165/0x690

The timer interrupt landed on the rbtree the copy had already run over.
No debug options are needed for this; KASAN reports the same write as an
out-of-bounds read of 13835058055416381440 bytes.

Documentation/trace/histogram.rst already states the rule, "must be a
long[] type", so enforce it once the name has been resolved. Names which
resolve to no field at all, "hitcount.stacktrace" and the common_*
pseudo-fields, are refused for the same reason: they hold no stacktrace
to read.

🎖@cveNotify

🚨 CVE-2026-97937
In the Linux kernel, the following vulnerability has been resolved:

ftrace: fork: Initialize function graph state before copy_exec_state()

dup_task_struct() copies the parent's task_struct, including ret_stack.
ftrace_graph_init_task() clears the copied function graph state, but it
currently runs after copy_exec_state().

For non-CLONE_VM forks, copy_exec_state() allocates a new task_exec_state.
If that allocation fails, copy_process() reaches bad_fork_free and
free_task() calls ftrace_graph_exit_task(). Since the child still carries
the parent's ret_stack pointer, the unwind frees the parent's active
function graph return stack. The parent subsequently accesses freed memory
from function_graph_enter_regs().

KASAN reports:

[ 22.190920] ==================================================================
[ 22.195899] BUG: KASAN: slab-use-after-free in function_graph_enter_regs+0xa76/0xb90
[ 22.200747] Write of size 8 at addr ff110000054dc0a8 by task repro/1
[ 22.205134]
[ 22.210770] CPU: 0 UID: 0 PID: 1 Comm: repro Not tainted 7.2.0-07732-g9328b3b03bdc-dirty #3 PREEMPT(lazy)
[ 22.212576] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 22.213750] Call Trace:
[ 22.215271] <TASK>
[ 22.216242] ? ftrace_stub_direct_tramp+0x10/0x10
[ 22.217774] dump_stack_lvl+0x4e/0x70
[ 22.220531] print_report+0x157/0x4b4
[ 22.223202] ? fixup_red_left+0x9/0x30
[ 22.224407] ? complete_report_info+0x83/0x110
[ 22.226679] ? function_graph_enter_regs+0xa76/0xb90
[ 22.228084] kasan_report+0xce/0x100
[ 22.230109] ? function_graph_enter_regs+0xa76/0xb90
[ 22.232860] ? stack_trace_save+0x4/0xd0
[ 22.234156] function_graph_enter_regs+0xa76/0xb90
[ 22.236090] ? kasan_save_stack+0x30/0x50
[ 22.237752] ? __pfx_function_graph_enter_regs+0x10/0x10
[ 22.238694] ? ring_buffer_lock_reserve+0x345/0xf80
[ 22.239628] ? stack_trace_save+0x4/0xd0
[ 22.242121] ? stack_trace_save+0x4/0xd0
[ 22.243588] ftrace_graph_func+0xda/0x160
[ 22.245362] ? ftrace_stub_direct_tramp+0x10/0x10
[ 22.246520] 0xffffffffa0000095
[ 22.250528] ? stack_trace_save+0x9/0xd0
[ 22.251757] ? ring_buffer_unlock_commit+0x11d/0x5c0
[ 22.253152] stack_trace_save+0x9/0xd0
[ 22.254264] kasan_save_stack+0x30/0x50
[ 22.273631] kasan_save_track+0x14/0x30
[ 22.276763] kasan_save_free_info+0x3b/0x70
[ 22.278296] __kasan_slab_free+0x43/0x70
[ 22.280157] kmem_cache_free+0xbf/0x3b0
[ 22.282963] ? ftrace_stub_direct_tramp+0x10/0x10
[ 22.284001] free_task+0xa2/0x160
[ 22.285699] ? ftrace_stub_direct_tramp+0x10/0x10
[ 22.286752] copy_process+0x2aae/0x7bc0

Initialize the child function graph state immediately after
dup_task_struct(), before the first fallible operation.

🎖@cveNotify

🚨 CVE-2026-97938
In the Linux kernel, the following vulnerability has been resolved:

reboot: fix cad_pid use-after-free race

cad_pid is a single kernel-wide struct pid pointer. proc_do_cad_pid()
reads it and passes it to pid_vnr() without protecting the lifetime of
the referenced struct pid. A concurrent writer can replace cad_pid and
drop the final reference to the old struct pid after the reader has
loaded the pointer but before pid_vnr() has finished dereferencing it,
causing a use-after-free.

kill_cad_pid() has the same lifetime race when it passes cad_pid to
kill_pid().

At the time this issue was reported, an unprivileged user could reach the
sysctl through user and PID namespaces because cad_pid was registered in
pid_table[]. Moving cad_pid back to the global reboot sysctl table
corrected that namespace and permission mismatch, but did not fix the
underlying lifetime race.

Fix this by treating cad_pid as an RCU-protected pointer at both read
sites and by waiting for a grace period before dropping the old reference
on the write side.

call_rcu(&old_pid->rcu, ...) cannot be used here because free_pid()
also queues pid->rcu; queueing the same rcu_head twice can corrupt the
RCU callback list.

Original KASAN crash stack:
kernel/pid.c:545 pid_nr_ns() # reads freed pid->level
kernel/pid.c:556 pid_vnr() # calls pid_nr_ns()
kernel/pid.c:775 proc_do_cad_pid() # calls pid_vnr(cad_pid)

🎖@cveNotify