mm/mm_init: deferred_grow_zone(): fix out-of-range first_deferred_pfn
In the Linux kernel, the following vulnerability has been resolved: mm/mm_init: deferred_grow_zone(): fix out-of-range first_deferred_pfn With CONFIG_DEFERRED_STRUCT_PAGE_INIT enabled, deferred_grow_zone() initializes struct pages early in boot to satisfy an allocation. With a large CMA reservation in place, the ranges deferred_init_memmap() finds may not add up to the allocation it was asked for, and the function ends up initializing the memory map of the entire zone and still falls short. That is fine in itself: the function accounts for it and leaves the caller to decide whether it now has enough memory. However, the update of pgdat->first_deferred_pfn that tracks where uninitialized memory map starts could overflow. If the node's RAM end is not aligned on PAGES_PER_SECTION boundaries and some deferred struct pages were initialized, pgdat->first_deferred_pfn would point past the end of the node's memory. deferred_init_memmap() later picks up from pgdat->first_deferred_pfn and hits a BUG_ON(), because it expects a pfn within its node. For example, when running a kernel with CONFIG_DEFERRED_STRUCT_PAGE_INIT=y and CONFIG_CMA=y using the following qemu command line qemu-system-x86_64 -enable-kvm -m 8032M -kernel bzImage \ -append "nokaslr cma=4768M@0x100000000" the kernel panics: kernel BUG at mm/mm_init.c:2131! CPU: 3 UID: 0 PID: 36 Comm: pgdatinit0 Not tainted 7.2.0-rc6 #1 RIP: 0010:deferred_init_memmap+0x1b8/0x1c0 RAX: 0000000000236000 R13: 0000000000238000 Call Trace: kthr
CVE-2026-93227
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-93227
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "3acb913c9d5bd8dcf61677ccba96d349e7681cf8",
"lessThan": "45489d4f95802903ab35799b400b346fa4e13151",
"versionType": "git"
},
{
"status": "affected",
"version": "3acb913c9d5bd8dcf61677ccba96d349e7681cf8",
"lessThan": "84339578c2d6936ac3a93cd1f0bbaa3468a988f2",
"versionType": "git"
},
{
"status": "affected",
"version": "3acb913c9d5bd8dcf61677ccba96d349e7681cf8",
"lessThan": "97090500d776c3f6d08e857e3a0a7cf092999094",
"versionType": "git"
}
],
"programFiles": [
"mm/mm_init.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.18"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.18",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.18.50",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.4",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"mm/mm_init.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-93227
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #37928 · Revision 1
- Added to Heist Feed
- Publisher date