GHSA-4MXC-9HCF-G45Q
Vulnerability from github – Published: 2026-10-06 09:31 – Updated: 2026-10-06 09:31In the Linux kernel, the following vulnerability has been resolved:
fs/dax: check zero or empty entry before converting xarray entry
Calling dax_to_folio() with empty entry causes kernel panic below when booting a VM with DAX enabled storage.
This patch checks empty entry before calling dax_to_folio() on dax_associate_entry(), dax_disassociate_entry(), and dax_busy_page().
Commit 98c183a4fccf ("fs/dax: don't disassociate zero page entries") added guards in the associate and disassociate paths, but the guards still come after dax_to_folio(), and dax_busy_page() still has the same problem.
[ 0.737679] EXT4-fs (pmem0p1): mounted filesystem 79676804-7c8b-491a-b2a6-9bae3c72af70 ro with ordered data mode. Quota mode: disabled. [ 0.737891] VFS: Mounted root (ext4 filesystem) readonly on device 259:1. [ 0.739119] devtmpfs: mounted [ 0.739476] Freeing unused kernel memory: 1920K [ 0.740156] Run /sbin/init as init process [ 0.740229] with arguments: [ 0.740286] /sbin/init [ 0.740321] with environment: [ 0.740369] HOME=/ [ 0.740400] TERM=linux [ 0.743162] Unable to handle kernel paging request at virtual address fffffdffbf000008 [ 0.743285] Mem abort info: [ 0.743316] ESR = 0x0000000096000006 [ 0.743371] EC = 0x25: DABT (current EL), IL = 32 bits [ 0.743444] SET = 0, FnV = 0 [ 0.743489] EA = 0, S1PTW = 0 [ 0.743545] FSC = 0x06: level 2 translation fault [ 0.743610] Data abort info: [ 0.743656] ISV = 0, ISS = 0x00000006, ISS2 = 0x00000000 [ 0.743720] CM = 0, WnR = 0, TnD = 0, TagAccess = 0 [ 0.743785] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [ 0.743848] swapper pgtable: 4k pages, 48-bit VAs, pgdp=00000000b9d17000 [ 0.743931] [fffffdffbf000008] pgd=10000000bfa3d403, p4d=10000000bfa3d403, pud=1000000040bfe403, pmd=0000000000000000 [ 0.744070] Internal error: Oops: 0000000096000006 [#1] SMP [ 0.748888] CPU: 0 UID: 0 PID: 1 Comm: init Not tainted 6.18.4 #1 NONE [ 0.749421] pstate: 004000c5 (nzcv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 0.749969] pc : dax_disassociate_entry.constprop.0+0x20/0x50 [ 0.750444] lr : dax_insert_entry+0xcc/0x408 [ 0.750802] sp : ffff80008000b9e0 [ 0.751083] x29: ffff80008000b9e0 x28: 0000000000000000 x27: 0000000000000000 [ 0.751682] x26: 0000000001963d01 x25: ffff0000004f7d90 x24: 0000000000000000 [ 0.752264] x23: 0000000000000000 x22: ffff80008000bcc8 x21: 0000000000000011 [ 0.752836] x20: ffff80008000ba90 x19: 0000000001963d01 x18: 0000000000000000 [ 0.753407] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 [ 0.753970] x14: ffffbf3154b9ae70 x13: 0000000000000000 x12: ffffbf3154b9ae70 [ 0.754548] x11: ffffffffffffffff x10: 0000000000000000 x9 : 0000000000000000 [ 0.755122] x8 : 000000000000000d x7 : 000000000000001f x6 : 0000000000000000 [ 0.755707] x5 : 0000000000000000 x4 : 0000000000000000 x3 : fffffdffc0000000 [ 0.756287] x2 : 0000000000000008 x1 : 0000000040000000 x0 : fffffdffbf000000 [ 0.756871] Call trace: [ 0.757107] dax_disassociate_entry.constprop.0+0x20/0x50 (P) [ 0.757592] dax_iomap_pte_fault+0x4fc/0x808 [ 0.757951] dax_iomap_fault+0x28/0x30 [ 0.758258] ext4_dax_huge_fault+0x80/0x2dc [ 0.758594] ext4_dax_fault+0x10/0x3c [ 0.758892] __do_fault+0x38/0x12c [ 0.759175] __handle_mm_fault+0x530/0xcf0 [ 0.759518] handle_mm_fault+0xe4/0x230 [ 0.759833] do_page_fault+0x17c/0x4dc [ 0.760144] do_translation_fault+0x30/0x38 [ 0.760483] do_mem_abort+0x40/0x8c [ 0.760771] el0_ia+0x4c/0x170 [ 0.761032] el0t_64_sync_handler+0xd8/0xdc [ 0.761371] el0t_64_sync+0x168/0x16c [ 0.761677] Code: f9453021 f2dfbfe3 cb813080 8b001860 (f9400401) [ 0.762168] ---[ end trace 0000000000000000 ]--- [ 0.762550] note: init[1] exited with irqs disabled [ 0.762631] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
{
"affected": [],
"aliases": [
"CVE-2026-98259"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-10-06T09:18:14Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/dax: check zero or empty entry before converting xarray entry\n\nCalling dax_to_folio() with empty entry causes kernel panic below when\nbooting a VM with DAX enabled storage.\n\nThis patch checks empty entry before calling dax_to_folio() on\ndax_associate_entry(), dax_disassociate_entry(), and dax_busy_page().\n\nCommit 98c183a4fccf (\"fs/dax: don\u0027t disassociate zero page entries\") added\nguards in the associate and disassociate paths, but the guards still come\nafter dax_to_folio(), and dax_busy_page() still has the same problem.\n\n[ 0.737679] EXT4-fs (pmem0p1): mounted filesystem 79676804-7c8b-491a-b2a6-9bae3c72af70 ro with ordered data mode. Quota mode: disabled.\n[ 0.737891] VFS: Mounted root (ext4 filesystem) readonly on device 259:1.\n[ 0.739119] devtmpfs: mounted\n[ 0.739476] Freeing unused kernel memory: 1920K\n[ 0.740156] Run /sbin/init as init process\n[ 0.740229] with arguments:\n[ 0.740286] /sbin/init\n[ 0.740321] with environment:\n[ 0.740369] HOME=/\n[ 0.740400] TERM=linux\n[ 0.743162] Unable to handle kernel paging request at virtual address fffffdffbf000008\n[ 0.743285] Mem abort info:\n[ 0.743316] ESR = 0x0000000096000006\n[ 0.743371] EC = 0x25: DABT (current EL), IL = 32 bits\n[ 0.743444] SET = 0, FnV = 0\n[ 0.743489] EA = 0, S1PTW = 0\n[ 0.743545] FSC = 0x06: level 2 translation fault\n[ 0.743610] Data abort info:\n[ 0.743656] ISV = 0, ISS = 0x00000006, ISS2 = 0x00000000\n[ 0.743720] CM = 0, WnR = 0, TnD = 0, TagAccess = 0\n[ 0.743785] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0\n[ 0.743848] swapper pgtable: 4k pages, 48-bit VAs, pgdp=00000000b9d17000\n[ 0.743931] [fffffdffbf000008] pgd=10000000bfa3d403, p4d=10000000bfa3d403, pud=1000000040bfe403, pmd=0000000000000000\n[ 0.744070] Internal error: Oops: 0000000096000006 [#1] SMP\n[ 0.748888] CPU: 0 UID: 0 PID: 1 Comm: init Not tainted 6.18.4 #1 NONE\n[ 0.749421] pstate: 004000c5 (nzcv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)\n[ 0.749969] pc : dax_disassociate_entry.constprop.0+0x20/0x50\n[ 0.750444] lr : dax_insert_entry+0xcc/0x408\n[ 0.750802] sp : ffff80008000b9e0\n[ 0.751083] x29: ffff80008000b9e0 x28: 0000000000000000 x27: 0000000000000000\n[ 0.751682] x26: 0000000001963d01 x25: ffff0000004f7d90 x24: 0000000000000000\n[ 0.752264] x23: 0000000000000000 x22: ffff80008000bcc8 x21: 0000000000000011\n[ 0.752836] x20: ffff80008000ba90 x19: 0000000001963d01 x18: 0000000000000000\n[ 0.753407] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000\n[ 0.753970] x14: ffffbf3154b9ae70 x13: 0000000000000000 x12: ffffbf3154b9ae70\n[ 0.754548] x11: ffffffffffffffff x10: 0000000000000000 x9 : 0000000000000000\n[ 0.755122] x8 : 000000000000000d x7 : 000000000000001f x6 : 0000000000000000\n[ 0.755707] x5 : 0000000000000000 x4 : 0000000000000000 x3 : fffffdffc0000000\n[ 0.756287] x2 : 0000000000000008 x1 : 0000000040000000 x0 : fffffdffbf000000\n[ 0.756871] Call trace:\n[ 0.757107] dax_disassociate_entry.constprop.0+0x20/0x50 (P)\n[ 0.757592] dax_iomap_pte_fault+0x4fc/0x808\n[ 0.757951] dax_iomap_fault+0x28/0x30\n[ 0.758258] ext4_dax_huge_fault+0x80/0x2dc\n[ 0.758594] ext4_dax_fault+0x10/0x3c\n[ 0.758892] __do_fault+0x38/0x12c\n[ 0.759175] __handle_mm_fault+0x530/0xcf0\n[ 0.759518] handle_mm_fault+0xe4/0x230\n[ 0.759833] do_page_fault+0x17c/0x4dc\n[ 0.760144] do_translation_fault+0x30/0x38\n[ 0.760483] do_mem_abort+0x40/0x8c\n[ 0.760771] el0_ia+0x4c/0x170\n[ 0.761032] el0t_64_sync_handler+0xd8/0xdc\n[ 0.761371] el0t_64_sync+0x168/0x16c\n[ 0.761677] Code: f9453021 f2dfbfe3 cb813080 8b001860 (f9400401)\n[ 0.762168] ---[ end trace 0000000000000000 ]---\n[ 0.762550] note: init[1] exited with irqs disabled\n[ 0.762631] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b",
"id": "GHSA-4mxc-9hcf-g45q",
"modified": "2026-10-06T09:31:32Z",
"published": "2026-10-06T09:31:32Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98259"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/185cd2f5fe1e3319853cf065905b2885ad0bcbf8"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/44ab7420ab52ab6c04bf225cac7c5c007cedd6c7"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8e2b8614039853e68d5338e37821e8bcee9fc05f"
}
],
"schema_version": "1.4.0",
"severity": []
}
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