CVE-2023-53007: tracing: Make sure trace_printk() can output as soon as it can be used

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-03-27 · updated 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: tracing: Make sure trace_printk() can output as soon as it can be used Currently trace_printk() can be used as soon as early_trace_init() is called from start_kernel(). But if a crash happens, and "ftrace_dump_on_oops" is set on the kernel command line, all you get will be: [ 0.456075] <idle>-0 0dN.2. 347519us : Unknown type 6 [ 0.456075] <idle>-0 0dN.2. 353141us : Unknown type 6 [ 0.456075] <idle>-0 0dN.2. 358684us : Unknown type 6 This is because the trace_printk() event (type 6) hasn't been registered yet. That gets done via an early_initcall(), which may be early, but not early enough. Instead of registering the trace_printk() event (and other ftrace events, which are not trace events) via an early_initcall(), have them registered at the same time that trace_printk() can be used. This way, if there is a crash before early_initcall(), then the trace_printk()s will actually be useful.

Affected products

Linux kernel: from 4.12 before 4.14.305; from 4.15 before 4.19.272; from 4.20 before 5.4.231; from 5.5 before 5.10.166; from 5.11 before 5.15.91; from 5.16 before 6.1.9 — fixed in 4.14.305, 4.19.272, 5.10.166, 5.15.91, 5.4.231, 6.1.9

How to fix

Upgrade to a fixed version: Linux kernel 4.14.305, 4.19.272, 5.10.166, 5.15.91. Check the vendor advisory for mitigations.

References

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