CVE-2026-46196
published 2026-05-28CVE-2026-46196: In the Linux kernel, the following vulnerability has been resolved: tracepoint: balance regfunc() on func_add() failure in tracepoint_add_func() When a…
medium5.5
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.
Affected
7 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| linux | linux | — | — |
| linux | linux | >= 8cf868affdc459beee1a941df0cfaba1673740e3 < 247ed8a969f981bfba3112fd4bb441eaa6cef59c | 247ed8a969f981bfba3112fd4bb441eaa6cef59c |
| linux | linux | >= 8cf868affdc459beee1a941df0cfaba1673740e3 < 7bcadb3c2bc1cf60690e931aadd35fb7bd646a49 | 7bcadb3c2bc1cf60690e931aadd35fb7bd646a49 |
| linux | linux | >= 8cf868affdc459beee1a941df0cfaba1673740e3 < 2c5b8eeea006eb694c81631cd5713d494b80be90 | 2c5b8eeea006eb694c81631cd5713d494b80be90 |
| linux | linux | >= 8cf868affdc459beee1a941df0cfaba1673740e3 < 342829e042ac00f3d68d442ea92873fb6683f494 | 342829e042ac00f3d68d442ea92873fb6683f494 |
| linux | linux | >= 8cf868affdc459beee1a941df0cfaba1673740e3 < fad217e16fded7f3c09f8637b0f6a224d58b5f2e | fad217e16fded7f3c09f8637b0f6a224d58b5f2e |
| linux | linux_kernel | — | — |