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Linux Kernel: Premature Kthread Shutdown Causes Data Leak

OESA-2026-1505
Summary

A fix has been made to the Linux Kernel to prevent a situation where a critical system thread is stopped too early, leading to potential data loss. This issue affects Linux systems and can result in system warnings and potential data corruption. To fix this, update your Linux kernel to the latest version.

What to do
  • Update kernel to version 5.10.0-303.0.0.206.oe2203sp4.
Affected software
VendorProductAffected versionsFix available
– kernel <= 5.10.0-303.0.0.206.oe2203sp4 5.10.0-303.0.0.206.oe2203sp4
Original title
kernel security update
Original description
The Linux Kernel, the operating system core itself.

Security Fix(es):

In the Linux kernel, the following vulnerability has been resolved:

bpf, cpumap: Make sure kthread is running before map update returns

The following warning was reported when running stress-mode enabled
xdp_redirect_cpu with some RT threads:

------------[ cut here ]------------
WARNING: CPU: 4 PID: 65 at kernel/bpf/cpumap.c:135
CPU: 4 PID: 65 Comm: kworker/4:1 Not tainted 6.5.0-rc2+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
Workqueue: events cpu_map_kthread_stop
RIP: 0010:put_cpu_map_entry+0xda/0x220
......
Call Trace:
&lt;TASK&gt;
? show_regs+0x65/0x70
? __warn+0xa5/0x240
......
? put_cpu_map_entry+0xda/0x220
cpu_map_kthread_stop+0x41/0x60
process_one_work+0x6b0/0xb80
worker_thread+0x96/0x720
kthread+0x1a5/0x1f0
ret_from_fork+0x3a/0x70
ret_from_fork_asm+0x1b/0x30
&lt;/TASK&gt;

The root cause is the same as commit 436901649731 (&quot;bpf: cpumap: Fix memory
leak in cpu_map_update_elem&quot;). The kthread is stopped prematurely by
kthread_stop() in cpu_map_kthread_stop(), and kthread() doesn&apos;t call
cpu_map_kthread_run() at all but XDP program has already queued some
frames or skbs into ptr_ring. So when __cpu_map_ring_cleanup() checks
the ptr_ring, it will find it was not emptied and report a warning.

An alternative fix is to use __cpu_map_ring_cleanup() to drop these
pending frames or skbs when kthread_stop() returns -EINTR, but it may
confuse the user, because these frames or skbs have been handled
correctly by XDP program. So instead of dropping these frames or skbs,
just make sure the per-cpu kthread is running before
__cpu_map_entry_alloc() returns.

After apply the fix, the error handle for kthread_stop() will be
unnecessary because it will always return 0, so just remove it.(CVE-2023-53577)

In the Linux kernel, the following vulnerability has been resolved:

drivers: base: Free devm resources when unregistering a device

In the current code, devres_release_all() only gets called if the device
has a bus and has been probed.

This leads to issues when using bus-less or driver-less devices where
the device might never get freed if a managed resource holds a reference
to the device. This is happening in the DRM framework for example.

We should thus call devres_release_all() in the device_del() function to
make sure that the device-managed actions are properly executed when the
device is unregistered, even if it has neither a bus nor a driver.

This is effectively the same change than commit 2f8d16a996da (&quot;devres:
release resources on device_del()&quot;) that got reverted by commit
a525a3ddeaca (&quot;driver core: free devres in device_release&quot;) over
memory leaks concerns.

This patch effectively combines the two commits mentioned above to
release the resources both on device_del() and device_release() and get
the best of both worlds.(CVE-2023-53596)

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()
-&gt; NO LOCK held
list_for_each_entry(sw, ..)
DMA interrupt
dma_do_tasklet()
-&gt; spin_lock(&amp;desc_lock)
list_move(sw-&gt;node, ...)
spin_unlock(&amp;desc_lock)
| dma_pool_free(sw) &lt;- FREED!
-&gt; access sw-&gt;desc &lt;- UAF!

This issue can be reproduced when running dmatest on the same channel with
multiple threads (threads_per_chan &gt; 1).

Fix by protecting the chain_running list iteration and descriptor access
with the chan-&gt;desc_lock spinlock.(CVE-2025-71221)

In the Linux kernel, the following vulnerability has been resolved:

migrate: correct lock ordering for hugetlb file folios

Syzbot has found a deadlock (analyzed by Lance Yang):

1) Task (5749): Holds folio_lock, then tries to acquire i_mmap_rwsem(read lock).
2) Task (5754): Holds i_mmap_rwsem(write lock), then tries to acquire
folio_lock.

migrate_pages()
-&gt; migrate_hugetlbs()
-&gt; unmap_and_move_huge_page() &lt;- Takes folio_lock!
-&gt; remove_migration_ptes()
-&gt; __rmap_walk_file()
-&gt; i_mmap_lock_read() &lt;- Waits for i_mmap_rwsem(read lock)!

hugetlbfs_fallocate()
-&gt; hugetlbfs_punch_hole() &lt;- Takes i_mmap_rwsem(write lock)!
-&gt; hugetlbfs_zero_partial_page()
-&gt; filemap_lock_hugetlb_folio()
-&gt; filemap_lock_folio()
-&gt; __filemap_get_folio &lt;- Waits for folio_lock!

The migration path is the one taking locks in the wrong order according to
the documentation at the top of mm/rmap.c. So expand the scope of the
existing i_mmap_lock to cover the calls to remove_migration_ptes() too.

This is (mostly) how it used to be after commit c0d0381ade79. That was
removed by 336bf30eb765 for both file &amp; anon hugetlb pages when it should
only have been removed for anon hugetlb pages.(CVE-2026-23097)

In the Linux kernel, the following vulnerability has been resolved:

nvmet-tcp: add bounds checks in nvmet_tcp_build_pdu_iovec

nvmet_tcp_build_pdu_iovec() could walk past cmd-&gt;req.sg when a PDU
length or offset exceeds sg_cnt and then use bogus sg-&gt;length/offset
values, leading to _copy_to_iter() GPF/KASAN. Guard sg_idx, remaining
entries, and sg-&gt;length/offset before building the bvec.(CVE-2026-23112)

In the Linux kernel, the following vulnerability has been resolved:

scsi: target: iscsi: Fix use-after-free in iscsit_dec_conn_usage_count()

In iscsit_dec_conn_usage_count(), the function calls complete() while
holding the conn-&gt;conn_usage_lock. As soon as complete() is invoked, the
waiter (such as iscsit_close_connection()) may wake up and proceed to free
the iscsit_conn structure.

If the waiter frees the memory before the current thread reaches
spin_unlock_bh(), it results in a KASAN slab-use-after-free as the function
attempts to release a lock within the already-freed connection structure.

Fix this by releasing the spinlock before calling complete().(CVE-2026-23216)
Published: 6 Mar 2026 · Updated: 6 Mar 2026 · First seen: 6 Mar 2026