CVE-2025-38031padata: do not leak refcount in reorder_work

Official description

In the Linux kernel, the following vulnerability has been resolved: padata: do not leak refcount in reorder_work A recent patch that addressed a UAF introduced a reference count leak: the parallel_data refcount is incremented unconditionally, regardless of the return value of queue_work(). If the work item is already queued, the incremented refcount is never decremented. Fix this by checking the return value of queue_work() and decrementing the refcount when necessary. Resolves: Unreferenced object 0xffff9d9f421e3d80 (size 192): comm "cryptomgr_probe", pid 157, jiffies 4294694003 hex dump (first 32 bytes): 80 8b cf 41 9f 9d ff ff b8 97 e0 89 ff ff ff ff ...A............ d0 97 e0 89 ff ff ff ff 19 00 00 00 1f 88 23 00 ..............#. backtrace (crc 838fb36): __kmalloc_cache_noprof+0x284/0x320 padata_alloc_pd+0x20/0x1e0 padata_alloc_shell+0x3b/0xa0 0xffffffffc040a54d cryptomgr_probe+0x43/0xc0 kthread+0xf6/0x1f0 ret_from_fork+0x2f/0x50 ret_from_fork_asm+0x1a/0x30

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/b9ad8e50e8589607e68e6c4cefa7f72bf35a2cb1
• https://git.kernel.org/stable/c/1a426abdf1c86882c9203dd8182f3b8274b89938
• https://git.kernel.org/stable/c/cceb15864e1612ebfbc10ec4e4dcd19a10c0056c
• https://git.kernel.org/stable/c/584a729615fa92f4de45480efb7e569d14be1516
• https://git.kernel.org/stable/c/5300e487487d7a2e3e1e6e9d8f03ed9452e4019e
• https://git.kernel.org/stable/c/1c65ae4988714716101555fe2b9830e33136d6fb
• https://git.kernel.org/stable/c/d6ebcde6d4ecf34f8495fb30516645db3aea8993
• https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
• https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html