| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2024-39477: mm/hugetlb: do not call vma_add_reservation upon ENOMEM |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| mm/hugetlb: do not call vma_add_reservation upon ENOMEM |
| |
| sysbot reported a splat [1] on __unmap_hugepage_range(). This is because |
| vma_needs_reservation() can return -ENOMEM if |
| allocate_file_region_entries() fails to allocate the file_region struct |
| for the reservation. |
| |
| Check for that and do not call vma_add_reservation() if that is the case, |
| otherwise region_abort() and region_del() will see that we do not have any |
| file_regions. |
| |
| If we detect that vma_needs_reservation() returned -ENOMEM, we clear the |
| hugetlb_restore_reserve flag as if this reservation was still consumed, so |
| free_huge_folio() will not increment the resv count. |
| |
| [1] https://lore.kernel.org/linux-mm/0000000000004096100617c58d54@google.com/T/#ma5983bc1ab18a54910da83416b3f89f3c7ee43aa |
| |
| The Linux kernel CVE team has assigned CVE-2024-39477 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.9 with commit df7a6d1f64056aec572162c5d35ed9ff86ece6f3 and fixed in 6.9.5 with commit aa998f9dcb34c28448f86e8f5490f20d5eb0eac7 |
| Issue introduced in 6.9 with commit df7a6d1f64056aec572162c5d35ed9ff86ece6f3 and fixed in 6.10 with commit 8daf9c702ee7f825f0de8600abff764acfedea13 |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2024-39477 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| mm/hugetlb.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/aa998f9dcb34c28448f86e8f5490f20d5eb0eac7 |
| https://git.kernel.org/stable/c/8daf9c702ee7f825f0de8600abff764acfedea13 |
