cbcvebase.
CVE-2024-56673
published 2024-12-27

CVE-2024-56673: In the Linux kernel, the following vulnerability has been resolved: riscv: mm: Do not call pmd dtor on vmemmap page table teardown The vmemmap's, which is used…

PriorityP421medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
EPSS
0.19%
8.5th percentile
In the Linux kernel, the following vulnerability has been resolved: riscv: mm: Do not call pmd dtor on vmemmap page table teardown The vmemmap's, which is used for RV64 with SPARSEMEM_VMEMMAP, page tables are populated using pmd (page middle directory) hugetables. However, the pmd allocation is not using the generic mechanism used by the VMA code (e.g. pmd_alloc()), or the RISC-V specific create_pgd_mapping()/alloc_pmd_late(). Instead, the vmemmap page table code allocates a page, and calls vmemmap_set_pmd(). This results in that the pmd ctor is *not* called, nor would it make sense to do so. Now, when tearing down a vmemmap page table pmd, the cleanup code would unconditionally, and incorrectly call the pmd dtor, which results in a crash (best case). This issue was found when running the HMM selftests: | tools/testing/selftests/mm# ./test_hmm.sh smoke | ... # when unloading the test_hmm.ko module | page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10915b | flags: 0x1000000000000000(node=0|zone=1) | raw: 1000000000000000 0000000000000000 dead000000000122 0000000000000000 | raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000 | page dumped because: VM_BUG_ON_PAGE(ptdesc->pmd_huge_pte) | ------------[ cut here ]------------ | kernel BUG at include/linux/mm.h:3080! | Kernel BUG [#1] | Modules linked in: test_hmm(-) sch_fq_codel fuse drm drm_panel_orientation_quirks backlight dm_mod | CPU: 1 UID: 0 PID: 514 Comm: modprobe Tainted: G W 6.12.0-00982-gf2a4f1682d07 #2 | Tainted: [W]=WARN | Hardware name: riscv-virtio qemu/qemu, BIOS 2024.10 10/01/2024 | epc : remove_pgd_mapping+0xbec/0x1070 | ra : remove_pgd_mapping+0xbec/0x1070 | epc : ffffffff80010a68 ra : ffffffff80010a68 sp : ff20000000a73940 | gp : ffffffff827b2d88 tp : ff6000008785da40 t0 : ffffffff80fbce04 | t1 : 0720072007200720 t2 : 706d756420656761 s0 : ff20000000a73a50 | s1 : ff6000008915cff8 a0 : 0000000000000039 a1 : 0000000000000008 | a2 : ff600003fff0de20 a3 : 00000

Affected

8 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 6.12.6-1 (forky)linux 6.12.6-1 (forky)
linuxlinux
linuxlinux>= c75a74f4ba19c904c0ae1e011ae2568449409ae4 < 344945806f2f7af68be98bac02836c867f223aa9344945806f2f7af68be98bac02836c867f223aa9
linuxlinux>= c75a74f4ba19c904c0ae1e011ae2568449409ae4 < 21f1b85c8912262adf51707e63614a114425eb1021f1b85c8912262adf51707e63614a114425eb10
linuxlinux_kernel
linuxlinux_kernel>= 0 < 6.12.6-16.12.6-1
linuxlinux_kernel>= 0 < 6.12.6-16.12.6-1
linuxlinux_kernel>= 6.11 < 6.12.66.12.6

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
osv5.5MEDIUM
vendor_debian5.5LOW
vendor_redhat5.5MEDIUM
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