Description
In the Linux kernel, the following vulnerability has been resolved:
x86/mm/pat: fix VM_PAT handling in COW mappings
PAT handling won't do the right thing in COW mappings: the first PTE (or,
in fact, all PTEs) can be replaced during write faults to point at anon
folios. Reliably recovering the correct PFN and cachemode using
follow_phys() from PTEs will not work in COW mappings.
Using follow_phys(), we might just get the address+protection of the anon
folio (which is very wrong), or fail on swap/nonswap entries, failing
follow_phys() and triggering a WARN_ON_ONCE() in untrack_pfn() and
track_pfn_copy(), not properly calling free_pfn_range().
In free_pfn_range(), we either wouldn't call memtype_free() or would call
it with the wrong range, possibly leaking memory.
To fix that, let's update follow_phys() to refuse returning anon folios,
and fallback to using the stored PFN inside vma->vm_pgoff for COW mappings
if we run into that.
We will now properly handle untrack_pfn() with COW mappings, where we
don't need the cachemode. We'll have to fail fork()->track_pfn_copy() if
the first page was replaced by an anon folio, though: we'd have to store
the cachemode in the VMA to make this work, likely growing the VMA size.
For now, lets keep it simple and let track_pfn_copy() just fail in that
case: it would have failed in the past with swap/nonswap entries already,
and it would have done the wrong thing with anon folios.
Simple reproducer to trigger the WARN_ON_ONCE() in untrack_pfn():
<--- C reproducer --->
#include <stdio.h>
#include <sys/mman.h>
#include <unistd.h>
#include <liburing.h>
int main(void)
{
struct io_uring_params p = {};
int ring_fd;
size_t size;
char *map;
ring_fd = io_uring_setup(1, &p);
if (ring_fd < 0) {
perror("io_uring_setup");
return 1;
}
size = p.sq_off.array + p.sq_entries * sizeof(unsigned);
/* Map the submission queue ring MAP_PRIVATE */
map = mmap(0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE,
ring_fd, IORING_OFF_SQ_RING);
if (map == MAP_FAILED) {
perror("mmap");
return 1;
}
/* We have at least one page. Let's COW it. */
*map = 0;
pause();
return 0;
}
<--- C reproducer --->
On a system with 16 GiB RAM and swap configured:
# ./iouring &
# memhog 16G
# killall iouring
[ 301.552930] ------------[ cut here ]------------
[ 301.553285] WARNING: CPU: 7 PID: 1402 at arch/x86/mm/pat/memtype.c:1060 untrack_pfn+0xf4/0x100
[ 301.553989] Modules linked in: binfmt_misc nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_g
[ 301.558232] CPU: 7 PID: 1402 Comm: iouring Not tainted 6.7.5-100.fc38.x86_64 #1
[ 301.558772] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebu4
[ 301.559569] RIP: 0010:untrack_pfn+0xf4/0x100
[ 301.559893] Code: 75 c4 eb cf 48 8b 43 10 8b a8 e8 00 00 00 3b 6b 28 74 b8 48 8b 7b 30 e8 ea 1a f7 000
[ 301.561189] RSP: 0018:ffffba2c0377fab8 EFLAGS: 00010282
[ 301.561590] RAX: 00000000ffffffea RBX: ffff9208c8ce9cc0 RCX: 000000010455e047
[ 301.562105] RDX: 07fffffff0eb1e0a RSI: 0000000000000000 RDI: ffff9208c391d200
[ 301.562628] RBP: 0000000000000000 R08: ffffba2c0377fab8 R09: 0000000000000000
[ 301.563145] R10: ffff9208d2292d50 R11: 0000000000000002 R12: 00007fea890e0000
[ 301.563669] R13: 0000000000000000 R14: ffffba2c0377fc08 R15: 0000000000000000
[ 301.564186] FS: 0000000000000000(0000) GS:ffff920c2fbc0000(0000) knlGS:0000000000000000
[ 301.564773] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 301.565197] CR2: 00007fea88ee8a20 CR3: 00000001033a8000 CR4: 0000000000750ef0
[ 301.565725] PKRU: 55555554
[ 301.565944] Call Trace:
[ 301.566148] <TASK>
[ 301.566325] ? untrack_pfn+0xf4/0x100
[ 301.566618] ? __warn+0x81/0x130
[ 301.566876] ? untrack_pfn+0xf4/0x100
[ 3
---truncated---
x86/mm/pat: fix VM_PAT handling in COW mappings
PAT handling won't do the right thing in COW mappings: the first PTE (or,
in fact, all PTEs) can be replaced during write faults to point at anon
folios. Reliably recovering the correct PFN and cachemode using
follow_phys() from PTEs will not work in COW mappings.
Using follow_phys(), we might just get the address+protection of the anon
folio (which is very wrong), or fail on swap/nonswap entries, failing
follow_phys() and triggering a WARN_ON_ONCE() in untrack_pfn() and
track_pfn_copy(), not properly calling free_pfn_range().
In free_pfn_range(), we either wouldn't call memtype_free() or would call
it with the wrong range, possibly leaking memory.
To fix that, let's update follow_phys() to refuse returning anon folios,
and fallback to using the stored PFN inside vma->vm_pgoff for COW mappings
if we run into that.
We will now properly handle untrack_pfn() with COW mappings, where we
don't need the cachemode. We'll have to fail fork()->track_pfn_copy() if
the first page was replaced by an anon folio, though: we'd have to store
the cachemode in the VMA to make this work, likely growing the VMA size.
For now, lets keep it simple and let track_pfn_copy() just fail in that
case: it would have failed in the past with swap/nonswap entries already,
and it would have done the wrong thing with anon folios.
Simple reproducer to trigger the WARN_ON_ONCE() in untrack_pfn():
<--- C reproducer --->
#include <stdio.h>
#include <sys/mman.h>
#include <unistd.h>
#include <liburing.h>
int main(void)
{
struct io_uring_params p = {};
int ring_fd;
size_t size;
char *map;
ring_fd = io_uring_setup(1, &p);
if (ring_fd < 0) {
perror("io_uring_setup");
return 1;
}
size = p.sq_off.array + p.sq_entries * sizeof(unsigned);
/* Map the submission queue ring MAP_PRIVATE */
map = mmap(0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE,
ring_fd, IORING_OFF_SQ_RING);
if (map == MAP_FAILED) {
perror("mmap");
return 1;
}
/* We have at least one page. Let's COW it. */
*map = 0;
pause();
return 0;
}
<--- C reproducer --->
On a system with 16 GiB RAM and swap configured:
# ./iouring &
# memhog 16G
# killall iouring
[ 301.552930] ------------[ cut here ]------------
[ 301.553285] WARNING: CPU: 7 PID: 1402 at arch/x86/mm/pat/memtype.c:1060 untrack_pfn+0xf4/0x100
[ 301.553989] Modules linked in: binfmt_misc nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_g
[ 301.558232] CPU: 7 PID: 1402 Comm: iouring Not tainted 6.7.5-100.fc38.x86_64 #1
[ 301.558772] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebu4
[ 301.559569] RIP: 0010:untrack_pfn+0xf4/0x100
[ 301.559893] Code: 75 c4 eb cf 48 8b 43 10 8b a8 e8 00 00 00 3b 6b 28 74 b8 48 8b 7b 30 e8 ea 1a f7 000
[ 301.561189] RSP: 0018:ffffba2c0377fab8 EFLAGS: 00010282
[ 301.561590] RAX: 00000000ffffffea RBX: ffff9208c8ce9cc0 RCX: 000000010455e047
[ 301.562105] RDX: 07fffffff0eb1e0a RSI: 0000000000000000 RDI: ffff9208c391d200
[ 301.562628] RBP: 0000000000000000 R08: ffffba2c0377fab8 R09: 0000000000000000
[ 301.563145] R10: ffff9208d2292d50 R11: 0000000000000002 R12: 00007fea890e0000
[ 301.563669] R13: 0000000000000000 R14: ffffba2c0377fc08 R15: 0000000000000000
[ 301.564186] FS: 0000000000000000(0000) GS:ffff920c2fbc0000(0000) knlGS:0000000000000000
[ 301.564773] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 301.565197] CR2: 00007fea88ee8a20 CR3: 00000001033a8000 CR4: 0000000000750ef0
[ 301.565725] PKRU: 55555554
[ 301.565944] Call Trace:
[ 301.566148] <TASK>
[ 301.566325] ? untrack_pfn+0xf4/0x100
[ 301.566618] ? __warn+0x81/0x130
[ 301.566876] ? untrack_pfn+0xf4/0x100
[ 3
---truncated---
Analysis
Analysis and contextual insights are available on OpenCVE Cloud.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
|||||||||||||||||||||||||||||||||
| Linux | Linux | affected |
|
Configuration 1 [-]
|
Configuration 2 [-]
|
| Package | CPE | Advisory | Released Date |
|---|---|---|---|
| Red Hat Enterprise Linux 8 | |||
| kernel-rt-0:4.18.0-553.22.1.rt7.363.el8_10 | cpe:/a:redhat:enterprise_linux:8::nfv | RHSA-2024:7001 | 2024-09-24T00:00:00Z |
| kernel-0:4.18.0-553.22.1.el8_10 | cpe:/o:redhat:enterprise_linux:8 | RHSA-2024:7000 | 2024-09-24T00:00:00Z |
| Red Hat Enterprise Linux 9 | |||
| kernel-0:5.14.0-503.11.1.el9_5 | cpe:/a:redhat:enterprise_linux:9 | RHSA-2024:9315 | 2024-11-12T00:00:00Z |
| kernel-0:5.14.0-503.11.1.el9_5 | cpe:/o:redhat:enterprise_linux:9 | RHSA-2024:9315 | 2024-11-12T00:00:00Z |
| Red Hat Enterprise Linux 9.4 Extended Update Support | |||
| kernel-0:5.14.0-427.68.1.el9_4 | cpe:/a:redhat:rhel_eus:9.4 | RHSA-2025:7526 | 2025-05-14T00:00:00Z |
No data available yet.
Remediation
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
Sign in to view the affected projects.
Advisories
| Source | ID | Title |
|---|---|---|
 Debian DLA |
DLA-3840-1 | linux security update |
| Debian DLA |
DLA-3842-1 | linux-5.10 security update |
 Ubuntu USN |
USN-6893-1 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-6893-2 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-6893-3 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-6896-1 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-6896-2 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-6896-3 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-6896-4 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-6896-5 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-6898-1 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-6898-2 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-6898-3 | Linux kernel kernel vulnerabilities |
| Ubuntu USN |
USN-6898-4 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-6917-1 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-6918-1 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-6919-1 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-6927-1 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-7019-1 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-7121-1 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-7121-2 | Linux kernel (Azure) vulnerabilities |
| Ubuntu USN |
USN-7121-3 | Linux kernel (Oracle) vulnerabilities |
| Ubuntu USN |
USN-7148-1 | Linux kernel vulnerabilities |
References
History
Tue, 12 May 2026 12:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
Tue, 23 Dec 2025 19:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Debian
Debian debian Linux Linux Linux linux Kernel |
|
| Weaknesses | CWE-401 | |
| CPEs | cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.9:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.9:rc2:*:*:*:*:*:* |
|
| Vendors & Products |
Debian
Debian debian Linux Linux Linux linux Kernel |
Wed, 14 May 2025 15:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Redhat rhel Eus
|
|
| CPEs | cpe:/a:redhat:rhel_eus:9.4 | |
| Vendors & Products |
Redhat rhel Eus
|
Fri, 22 Nov 2024 12:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
Wed, 13 Nov 2024 02:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| CPEs | cpe:/a:redhat:enterprise_linux:9 cpe:/o:redhat:enterprise_linux:9 |
Tue, 05 Nov 2024 10:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
Tue, 24 Sep 2024 11:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| CPEs | cpe:/o:redhat:enterprise_linux:8 |
Tue, 24 Sep 2024 06:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Redhat
Redhat enterprise Linux |
|
| CPEs | cpe:/a:redhat:enterprise_linux:8::nfv | |
| Vendors & Products |
Redhat
Redhat enterprise Linux |
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-05-12T11:52:17.843Z
Reserved: 2024-05-17T13:50:33.110Z
Link: CVE-2024-35877
Vulnrichment
Updated: 2024-08-02T03:21:48.797Z
NVD
Status : Modified
Published: 2024-05-19T09:15:08.990
Modified: 2026-05-12T12:16:38.203
Link: CVE-2024-35877
Redhat
OpenCVE Enrichment
No data.
Weaknesses