CVE-2022-49675 tick/nohz: unexport __init-annotated tick_nohz_full_setup()
A kernel panic can occur if a module attempts to access an exported initialization function that has been freed, causing a denial of service.
- 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
What is CVE-2022-49675?
CVE-2022-49675 is a medium-severity vulnerability in Linux kernel, published on 26 Feb 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:
tick/nohz: unexport __init-annotated tick_nohz_full_setup()
EXPORT_SYMBOL and __init is a bad combination because the .init.text section is freed up after the initialization. Hence, modules cannot use symbols annotated __init. The access to a freed symbol may end up with kernel panic.
modpost used to detect it, but it had been broken for a decade.
Commit 28438794aba4 ("modpost: fix section mismatch check for exported init/exit sections") fixed it so modpost started to warn it again, then this showed up:
MODPOST vmlinux.symvers WARNING: modpost: vmlinux.o(___ksymtab_gpl+tick_nohz_full_setup+0x0): Section mismatch in reference from the variable __ksymtab_tick_nohz_full_setup to the function .init.text:tick_nohz_full_setup() The symbol tick_nohz_full_setup is exported and annotated __init Fix this by removing the __init annotation of tick_nohz_full_setup or drop the export.
Drop the export because tick_nohz_full_setup() is only called from the built-in code in kernel/sched/isolation.c.
Weakness: CWE-908
Which versions are affected by CVE-2022-49675?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2022-49675?
Apply the vendor's patch.
Is CVE-2022-49675 being exploited?
There is no known exploitation of CVE-2022-49675 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2022-49675, GHSA-vq7c-8j8c-5xqp, UBUNTU-CVE-2022-49675.