Bugzilla – Bug 1223054
VUL-0: CVE-2024-26850: kernel: mm/debug_vm_pgtable: BUG_ON with pud advanced test
Last modified: 2024-04-18 11:36:20 UTC
In the Linux kernel, the following vulnerability has been resolved: mm/debug_vm_pgtable: fix BUG_ON with pud advanced test Architectures like powerpc add debug checks to ensure we find only devmap PUD pte entries. These debug checks are only done with CONFIG_DEBUG_VM. This patch marks the ptes used for PUD advanced test devmap pte entries so that we don't hit on debug checks on architecture like ppc64 as below. WARNING: CPU: 2 PID: 1 at arch/powerpc/mm/book3s64/radix_pgtable.c:1382 radix__pud_hugepage_update+0x38/0x138 .... NIP [c0000000000a7004] radix__pud_hugepage_update+0x38/0x138 LR [c0000000000a77a8] radix__pudp_huge_get_and_clear+0x28/0x60 Call Trace: [c000000004a2f950] [c000000004a2f9a0] 0xc000000004a2f9a0 (unreliable) [c000000004a2f980] [000d34c100000000] 0xd34c100000000 [c000000004a2f9a0] [c00000000206ba98] pud_advanced_tests+0x118/0x334 [c000000004a2fa40] [c00000000206db34] debug_vm_pgtable+0xcbc/0x1c48 [c000000004a2fc10] [c00000000000fd28] do_one_initcall+0x60/0x388 Also kernel BUG at arch/powerpc/mm/book3s64/pgtable.c:202! .... NIP [c000000000096510] pudp_huge_get_and_clear_full+0x98/0x174 LR [c00000000206bb34] pud_advanced_tests+0x1b4/0x334 Call Trace: [c000000004a2f950] [000d34c100000000] 0xd34c100000000 (unreliable) [c000000004a2f9a0] [c00000000206bb34] pud_advanced_tests+0x1b4/0x334 [c000000004a2fa40] [c00000000206db34] debug_vm_pgtable+0xcbc/0x1c48 [c000000004a2fc10] [c00000000000fd28] do_one_initcall+0x60/0x388 References: http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2024-26850 https://www.cve.org/CVERecord?id=CVE-2024-26850 https://git.kernel.org/stable/c/720da1e593b85a550593b415bf1d79a053133451 https://git.kernel.org/stable/c/d2a9510c0e39d06f5544075c13040407bdbf2803 https://git.kernel.org/stable/c/eeeddf85fc58d48c58ad916e4ca12363ebd8ab21 https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2024/CVE-2024-26850.mbox https://bugzilla.redhat.com/show_bug.cgi?id=2275752
These are VM_BUG_ON and we do not enable CONFIG_DEBUG_VM so this doesn't affect any of our kernels.
(In reply to Michal Hocko from comment #1) > These are VM_BUG_ON and we do not enable CONFIG_DEBUG_VM so this doesn't > affect any of our kernels. Thanks Michal. Closing