OESA-2026-1505

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: <TASK> ? 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 </TASK>

The root cause is the same as commit 436901649731 ("bpf: cpumap: Fix memory leak in cpu_map_update_elem"). The kthread is stopped prematurely by kthread_stop() in cpu_map_kthread_stop(), and kthread() doesn'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 ("devres: release resources on device_del()") that got reverted by commit a525a3ddeaca ("driver core: free devres in device_release") 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() -> 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.(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() -> migrate_hugetlbs() -> unmap_and_move_huge_page() <- Takes folio_lock! -> remove_migration_ptes() -> __rmap_walk_file() -> i_mmap_lock_read() <- Waits for i_mmap_rwsem(read lock)!

hugetlbfs_fallocate() -> hugetlbfs_punch_hole() <- Takes i_mmap_rwsem(write lock)! -> hugetlbfs_zero_partial_page() -> filemap_lock_hugetlb_folio() -> filemap_lock_folio() -> __filemap_get_folio <- 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 & 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->req.sg when a PDU length or offset exceeds sg_cnt and then use bogus sg->length/offset values, leading to _copy_to_iter() GPF/KASAN. Guard sg_idx, remaining entries, and sg->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->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)