CVE-2026-99093
Full vulnerability record from the local CVENow database.
Description
In the Linux kernel, the following vulnerability has been resolved: mm: don't schedule deferred kernel page table freeing while booting Booting with a boot-time function tracer and a filter, for example ftrace=function ftrace_filter=pud_free_pmd_page panics on 7.3-rc4 as soon as the tracer starts: [ 23.531178] Starting tracer 'function' [ 23.675800] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000038: 0000 [#1] SMP KASAN NOPTI [ 23.819917] KASAN: null-ptr-deref in range [0x00000000000001c0-0x00000000000001c7] [ 23.964025] CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 7.3.0-rc4-fe2ec83746e5-with-fixes-v2+ #195 PREEMPT(undef) [ 24.252248] RIP: 0010:__queue_work+0xab/0xf00 [ 25.981629] Call Trace: [ 26.125727] <TASK> [ 26.413912] ? pagetable_free_kernel+0x20/0x120 [ 26.990283] queue_work_on+0x97/0xf0 [ 27.134382] __cpa_collapse_large_pages+0x501/0x6f0 [ 27.566662] cpa_flush+0x394/0x620 [ 27.998953] change_page_attr_set_clr+0x321/0x4a0 [ 29.151729] set_memory_rox+0xa2/0xf0 [ 29.584018] create_trampoline+0x431/0x6f0 ... [ 44.343347] Kernel panic - not syncing: Attempted to kill the idle task! The boot-time tracer is started from early_trace_init(), which runs before workqueue_init_early(). Making its trampoline read-only splits a large page, and CPA collapses it again right away. The split table has been a kernel page table since commit 9e4a3ec3411b ("x86/mm/pat: Allocate split page tables as kernel page tables"), so the collapse frees it through pagetable_free_kernel(), which queues work on system_percpu_wq - still NULL at that point. That commit is correct in itself; it only lets CPA reach pagetable_free_kernel() before the workqueue that function relies on exists. Keep putting the table on the list, but don't schedule the work while the system is still booting. A core_initcall schedules it once to free whatever was queued by then.
View original CVE JSON
{
"id": "CVE-2026-99093",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-10-26T15:16:48.253",
"lastModified": "2026-10-26T15:16:48.253",
"vulnStatus": "Received",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm: don't schedule deferred kernel page table freeing while booting\n\nBooting with a boot-time function tracer and a filter, for example\n\n ftrace=function ftrace_filter=pud_free_pmd_page\n\npanics on 7.3-rc4 as soon as the tracer starts:\n\n [ 23.531178] Starting tracer 'function'\n [ 23.675800] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000038: 0000 [#1] SMP KASAN NOPTI\n [ 23.819917] KASAN: null-ptr-deref in range [0x00000000000001c0-0x00000000000001c7]\n [ 23.964025] CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 7.3.0-rc4-fe2ec83746e5-with-fixes-v2+ #195 PREEMPT(undef)\n [ 24.252248] RIP: 0010:__queue_work+0xab/0xf00\n [ 25.981629] Call Trace:\n [ 26.125727] <TASK>\n [ 26.413912] ? pagetable_free_kernel+0x20/0x120\n [ 26.990283] queue_work_on+0x97/0xf0\n [ 27.134382] __cpa_collapse_large_pages+0x501/0x6f0\n [ 27.566662] cpa_flush+0x394/0x620\n [ 27.998953] change_page_attr_set_clr+0x321/0x4a0\n [ 29.151729] set_memory_rox+0xa2/0xf0\n [ 29.584018] create_trampoline+0x431/0x6f0\n ...\n [ 44.343347] Kernel panic - not syncing: Attempted to kill the idle task!\n\nThe boot-time tracer is started from early_trace_init(), which runs\nbefore workqueue_init_early(). Making its trampoline read-only splits a\nlarge page, and CPA collapses it again right away. The split table has\nbeen a kernel page table since commit 9e4a3ec3411b\n(\"x86/mm/pat: Allocate split page tables as kernel page tables\"), so the\ncollapse frees it through pagetable_free_kernel(), which queues work on\nsystem_percpu_wq - still NULL at that point. That commit is correct in\nitself; it only lets CPA reach pagetable_free_kernel() before the\nworkqueue that function relies on exists.\n\nKeep putting the table on the list, but don't schedule the work while\nthe system is still booting. A core_initcall schedules it once to free\nwhatever was queued by then."
}
],
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "unaffected",
"programFiles": [
"mm/pgtable-generic.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "84e0cd79d57f06b872154eb5d8f610584133f260",
"lessThan": "7a25ca170c12a9328f6fcf4410713beb516b01c0",
"versionType": "git",
"status": "affected"
},
{
"version": "922873cf4fc34124215070a8ad391bf831538bb9",
"lessThan": "df6c704a08bc0925d5db047b0a6221f962bda4d9",
"versionType": "git",
"status": "affected"
},
{
"version": "9e4a3ec3411bb6bb59e3c1f29b75609f1e87aac4",
"lessThan": "2fb552b0bee70c24c092720028ab4620f5eb2646",
"versionType": "git",
"status": "affected"
}
]
},
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "unaffected",
"programFiles": [
"mm/pgtable-generic.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "6.18.53",
"lessThan": "6.18.57",
"versionType": "semver",
"status": "affected"
},
{
"version": "7.2.7",
"lessThan": "7.2.11",
"versionType": "semver",
"status": "affected"
}
]
}
]
}
],
"metrics": {},
"references": [
{
"url": "https://git.kernel.org/stable/c/2fb552b0bee70c24c092720028ab4620f5eb2646",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/7a25ca170c12a9328f6fcf4410713beb516b01c0",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/df6c704a08bc0925d5db047b0a6221f962bda4d9",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
]
}