Bug 2395311 (CVE-2022-50271)

Summary: CVE-2022-50271 kernel: vhost/vsock: Use kvmalloc/kvfree for larger packets
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Version: unspecifiedKeywords: Security
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OS: Linux   
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Description OSIDB Bzimport 2025-09-15 15:06:49 UTC 
In the Linux kernel, the following vulnerability has been resolved:

vhost/vsock: Use kvmalloc/kvfree for larger packets.

When copying a large file over sftp over vsock, data size is usually 32kB,
and kmalloc seems to fail to try to allocate 32 32kB regions.

 vhost-5837: page allocation failure: order:4, mode:0x24040c0
 Call Trace:
  [<ffffffffb6a0df64>] dump_stack+0x97/0xdb
  [<ffffffffb68d6aed>] warn_alloc_failed+0x10f/0x138
  [<ffffffffb68d868a>] ? __alloc_pages_direct_compact+0x38/0xc8
  [<ffffffffb664619f>] __alloc_pages_nodemask+0x84c/0x90d
  [<ffffffffb6646e56>] alloc_kmem_pages+0x17/0x19
  [<ffffffffb6653a26>] kmalloc_order_trace+0x2b/0xdb
  [<ffffffffb66682f3>] __kmalloc+0x177/0x1f7
  [<ffffffffb66e0d94>] ? copy_from_iter+0x8d/0x31d
  [<ffffffffc0689ab7>] vhost_vsock_handle_tx_kick+0x1fa/0x301 [vhost_vsock]
  [<ffffffffc06828d9>] vhost_worker+0xf7/0x157 [vhost]
  [<ffffffffb683ddce>] kthread+0xfd/0x105
  [<ffffffffc06827e2>] ? vhost_dev_set_owner+0x22e/0x22e [vhost]
  [<ffffffffb683dcd1>] ? flush_kthread_worker+0xf3/0xf3
  [<ffffffffb6eb332e>] ret_from_fork+0x4e/0x80
  [<ffffffffb683dcd1>] ? flush_kthread_worker+0xf3/0xf3

Work around by doing kvmalloc instead.
Comment 1 Jon Moroney 2025-09-15 23:09:15 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025091505-CVE-2022-50271-2175@gregkh/T