# CVE-2023-53509: qed: allow sleep in qed_mcp_trace_dump()

> A bug in the Linux kernel qed driver causes excessive CPU blocking during trace dumps, leading to thread scheduling delays and potential denial of service.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 1 Oct 2025
- **Updated:** 11 May 2026
- **Also known as:** AZL-75107, BELL-CVE-2023-53509, DEBIAN-CVE-2023-53509, GHSA-xj77-m3jq-h2r8, ROOT-OS-DEBIAN-11-CVE-2023-53509, ROOT-OS-UBUNTU-2204-CVE-2023-53509, UBUNTU-CVE-2023-53509

## What is CVE-2023-53509?

CVE-2023-53509 is a medium-severity denial of service vulnerability in Linux kernel, published on 1 Oct 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

qed: allow sleep in qed_mcp_trace_dump()

By default, qed_mcp_cmd_and_union() delays 10us at a time in a loop
that can run 500K times, so calls to qed_mcp_nvm_rd_cmd()
may block the current thread for over 5s.
We observed thread scheduling delays over 700ms in production,
with stacktraces pointing to this code as the culprit.

qed_mcp_trace_dump() is called from ethtool, so sleeping is permitted.
It already can sleep in qed_mcp_halt(), which calls qed_mcp_cmd().
Add a "can sleep" parameter to qed_find_nvram_image() and
qed_nvram_read() so they can sleep during qed_mcp_trace_dump().
qed_mcp_trace_get_meta_info() and qed_mcp_trace_read_meta(),
called only by qed_mcp_trace_dump(), allow these functions to sleep.
I can't tell if the other caller (qed_grc_dump_mcp_hw_dump()) can sleep,
so keep b_can_sleep set to false when it calls these functions.

An example stacktrace from a custom warning we added to the kernel
showing a thread that has not scheduled despite long needing resched:
[ 2745.362925,17] ------------[ cut here ]------------
[ 2745.362941,17] WARNING: CPU: 23 PID: 5640 at arch/x86/kernel/irq.c:233 do_IRQ+0x15e/0x1a0()
[ 2745.362946,17] Thread not rescheduled for 744 ms after irq 99
[ 2745.362956,17] Modules linked in: ...
[ 2745.363339,17] CPU: 23 PID: 5640 Comm: lldpd Tainted: P           O    4.4.182+ #202104120910+6d1da174272d.61x
[ 2745.363343,17] Hardware name: FOXCONN MercuryB/Quicksilver Controller, BIOS H11P1N09 07/08/2020
[ 2745.363346,17]  0000000000000000 ffff885ec07c3ed8 ffffffff8131eb2f ffff885ec07c3f20
[ 2745.363358,17]  ffffffff81d14f64 ffff885ec07c3f10 ffffffff81072ac2 ffff88be98ed0000
[ 2745.363369,17]  0000000000000063 0000000000000174 0000000000000074 0000000000000000
[ 2745.363379,17] Call Trace:
[ 2745.363382,17]  <IRQ>  [<ffffffff8131eb2f>] dump_stack+0x8e/0xcf
[ 2745.363393,17]  [<ffffffff81072ac2>] warn_slowpath_common+0x82/0xc0
[ 2745.363398,17]  [<ffffffff81072b4c>] warn_slowpath_fmt+0x4c/0x50
[ 2745.363404,17]  [<ffffffff810d5a8e>] ? rcu_irq_exit+0xae/0xc0
[ 2745.363408,17]  [<ffffffff817c99fe>] do_IRQ+0x15e/0x1a0
[ 2745.363413,17]  [<ffffffff817c7ac9>] common_interrupt+0x89/0x89
[ 2745.363416,17]  <EOI>  [<ffffffff8132aa74>] ? delay_tsc+0x24/0x50
[ 2745.363425,17]  [<ffffffff8132aa04>] __udelay+0x34/0x40
[ 2745.363457,17]  [<ffffffffa04d45ff>] qed_mcp_cmd_and_union+0x36f/0x7d0 [qed]
[ 2745.363473,17]  [<ffffffffa04d5ced>] qed_mcp_nvm_rd_cmd+0x4d/0x90 [qed]
[ 2745.363490,17]  [<ffffffffa04e1dc7>] qed_mcp_trace_dump+0x4a7/0x630 [qed]
[ 2745.363504,17]  [<ffffffffa04e2556>] ? qed_fw_asserts_dump+0x1d6/0x1f0 [qed]
[ 2745.363520,17]  [<ffffffffa04e4ea7>] qed_dbg_mcp_trace_get_dump_buf_size+0x37/0x80 [qed]
[ 2745.363536,17]  [<ffffffffa04ea881>] qed_dbg_feature_size+0x61/0xa0 [qed]
[ 2745.363551,17]  [<ffffffffa04eb427>] qed_dbg_all_data_size+0x247/0x260 [qed]
[ 2745.363560,17]  [<ffffffffa0482c10>] qede_get_regs_len+0x30/0x40 [qede]
[ 2745.363566,17]  [<ffffffff816c9783>] ethtool_get_drvinfo+0xe3/0x190
[ 2745.363570,17]  [<ffffffff816cc152>] dev_ethtool+0x1362/0x2140
[ 2745.363575,17]  [<ffffffff8109bcc6>] ? finish_task_switch+0x76/0x260
[ 2745.363580,17]  [<ffffffff817c2116>] ? __schedule+0x3c6/0x9d0
[ 2745.363585,17]  [<ffffffff810dbd50>] ? hrtimer_start_range_ns+0x1d0/0x370
[ 2745.363589,17]  [<ffffffff816c1e5b>] ? dev_get_by_name_rcu+0x6b/0x90
[ 2745.363594,17]  [<ffffffff816de6a8>] dev_ioctl+0xe8/0x710
[ 2745.363599,17]  [<ffffffff816a58a8>] sock_do_ioctl+0x48/0x60
[ 2745.363603,17]  [<ffffffff816a5d87>] sock_ioctl+0x1c7/0x280
[ 2745.363608,17]  [<ffffffff8111f393>] ? seccomp_phase1+0x83/0x220
[ 2745.363612,17]  [<ffffffff811e3503>] do_vfs_ioctl+0x2b3/0x4e0
[ 2745.363616,17]  [<ffffffff811e3771>] SyS_ioctl+0x41/0x70
[ 2745.363619,17]  [<ffffffff817c6ffe>] entry_SYSCALL_64_fastpath+0x1e/0x79
[ 2745.363622,17] ---[ end trace f6954aa440266421 ]---

## Which versions are affected by CVE-2023-53509?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2023-53509?

Apply the vendor's patch.

## Is CVE-2023-53509 being exploited?

There is no known exploitation of CVE-2023-53509 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-53509 and fix it if it is affected.

What it is: CVE-2023-53509 is a medium-severity denial of service vulnerability in Linux kernel, published on 1 Oct 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-53509 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2023-53509/ (Markdown: https://insights.sbomify.com/CVE-2023-53509/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-53509
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-53509
- OSV: https://osv.dev/vulnerability/CVE-2023-53509

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-53509/
Summaries are generated and may contain mistakes; the official description above is the record.