Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: tracing: Fix WARN_ON in tracing_buffers_mmap_close When a process forks, the child process copies the parent's VMAs but the user_mapped reference count is not incremented. As a result, when both the parent and child processes exit, tracing_buffers_mmap_close() is called twice. On the second call, user_mapped is already 0, causing the function to return -ENODEV and triggering a WARN_ON. Normally, this isn't an issue as the memory is mapped with VM_DONTCOPY set. But this is only a hint, and the application can call madvise(MADVISE_DOFORK) which resets the VM_DONTCOPY flag. When the application does that, it can trigger this issue on fork. Fix it by incrementing the user_mapped reference count without re-mapping the pages in the VMA's open callback.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected cf9f0f7c4c5bb45e7bb270e48bab6f7837825a64 before 91f3e8d84c89918769e71393f839c9fefadc2580; affected cf9f0f7c4c5bb45e7bb270e48bab6f7837825a64 before cdd96641b64297a2db42676f051362b76280a58b; affected cf9f0f7c4c5bb45e7bb270e48bab6f7837825a64 before b0f269ba6fefe9e3cb9feedcf78fcd0b633800c0; affected cf9f0f7c4c5bb45e7bb270e48bab6f7837825a64 before e39bb9e02b68942f8e9359d2a3efe7d37ae6be0e |
| Linux / Linux | affected 6.10; unaffected 0 before 6.10; unaffected 6.12.77 through 6.12.*; unaffected 6.18.17 through 6.18.*; unaffected 6.19.7 through 6.19.*; unaffected 7.0 through * |
CWE
No CWE identifiers supplied.