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CVE-2026-46196

tracepoint: balance regfunc() on func_add() failure in tracepoint_add_func()

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.259, 5.15.210, 6.1.176, 6.6.140, 6.12.88, and 2 more
None on Exploit-DB, Metasploit or GitHub

Summary

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.

Timeline

  1. CVE published
  2. Record last updated

Affected versions

  • Linux 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 Linux

    4.10

  • KernelLinux

    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

References 8

git.kernel.org