Bug 2348265 (CVE-2022-49625)

Summary: CVE-2022-49625 kernel: sfc: fix kernel panic when creating VF
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: low    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2025-02-26 03:23:23 UTC 
In the Linux kernel, the following vulnerability has been resolved:

sfc: fix kernel panic when creating VF

When creating VFs a kernel panic can happen when calling to
efx_ef10_try_update_nic_stats_vf.

When releasing a DMA coherent buffer, sometimes, I don't know in what
specific circumstances, it has to unmap memory with vunmap. It is
disallowed to do that in IRQ context or with BH disabled. Otherwise, we
hit this line in vunmap, causing the crash:
  BUG_ON(in_interrupt());

This patch reenables BH to release the buffer.

Log messages when the bug is hit:
 kernel BUG at mm/vmalloc.c:2727!
 invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
 CPU: 6 PID: 1462 Comm: NetworkManager Kdump: loaded Tainted: G          I      --------- ---  5.14.0-119.el9.x86_64 #1
 Hardware name: Dell Inc. PowerEdge R740/06WXJT, BIOS 2.8.2 08/27/2020
 RIP: 0010:vunmap+0x2e/0x30
 ...skip...
 Call Trace:
  __iommu_dma_free+0x96/0x100
  efx_nic_free_buffer+0x2b/0x40 [sfc]
  efx_ef10_try_update_nic_stats_vf+0x14a/0x1c0 [sfc]
  efx_ef10_update_stats_vf+0x18/0x40 [sfc]
  efx_start_all+0x15e/0x1d0 [sfc]
  efx_net_open+0x5a/0xe0 [sfc]
  __dev_open+0xe7/0x1a0
  __dev_change_flags+0x1d7/0x240
  dev_change_flags+0x21/0x60
  ...skip...
Comment 1 Avinash Hanwate 2025-02-26 12:23:48 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025022616-CVE-2022-49625-2fa2@gregkh/T
Comment 4 Avinash Hanwate 2025-02-27 14:46:10 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025022616-CVE-2022-49625-2fa2@gregkh/T