fs/proc: task_mmu.c: don't read mapcount for migration entry
In the Linux kernel, the following vulnerability has been resolved: fs/proc: task_mmu.c: don't read mapcount for migration entry The syzbot reported the below BUG: kernel BUG at include/linux/page-flags.h:785! invalid opcode: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 4392 Comm: syz-executor560 Not tainted 5.16.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:PageDoubleMap include/linux/page-flags.h:785 [inline] RIP: 0010:__page_mapcount+0x2d2/0x350 mm/util.c:744 Call Trace: page_mapcount include/linux/mm.h:837 [inline] smaps_account+0x470/0xb10 fs/proc/task_mmu.c:466 smaps_pte_entry fs/proc/task_mmu.c:538 [inline] smaps_pte_range+0x611/0x1250 fs/proc/task_mmu.c:601 walk_pmd_range mm/pagewalk.c:128 [inline] walk_pud_range mm/pagewalk.c:205 [inline] walk_p4d_range mm/pagewalk.c:240 [inline] walk_pgd_range mm/pagewalk.c:277 [inline] __walk_page_range+0xe23/0x1ea0 mm/pagewalk.c:379 walk_page_vma+0x277/0x350 mm/pagewalk.c:530 smap_gather_stats.part.0+0x148/0x260 fs/proc/task_mmu.c:768 smap_gather_stats fs/proc/task_mmu.c:741 [inline] show_smap+0xc6/0x440 fs/proc/task_mmu.c:822 seq_read_iter+0xbb0/0x1240 fs/seq_file.c:272 seq_read+0x3e0/0x5b0 fs/seq_file.c:162 vfs_read+0x1b5/0x600 fs/read_write.c:479 ksys_read+0x12d/0x250 fs/read_write.c:619 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae The reproducer was trying to read /proc/$PID/smaps when calling MADV_FREE at the mean time. MADV_FREE may split THPs if it is called for partial THP. It may trigger the below race: CPU A CPU B ----- ----- smaps walk: MADV_FREE: page_mapcount() PageCompound() split_huge_page() page = compound_head(page) PageDoubleMap(page) When calling PageDoubleMap() this page is not a tail page of THP anymore so the BUG is triggered. This could be fixed by elevated refcount of the page before calling mapcount, but that would prevent it from counting migration entries, and it seems overkilling because the race just could happen when PMD is split so all PTE entries of tail pages are actually migration entries, and smaps_account() does treat migration entries as mapcount == 1 as Kirill pointed out. Add a new parameter for smaps_account() to tell this entry is migration entry then skip calling page_mapcount(). Don't skip getting mapcount for device private entries since they do track references with mapcount. Pagemap also has the similar issue although it was not reported. Fixed it as well. [shy828301@gmail.com: v4] [nathan@kernel.org: avoid unused variable warning in pagemap_pmd_range()]
- Published
- Jul 16, 2024
- Updated
- Jun 17, 2026
- EPSS
- 0.3% · 20th percentile
- CWE
- —
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Report tools
Action score
22
Monitor
Low priority for now.
- CVSS
- 22 / 40 · 5.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.3%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpAffected systems
| Vendor | Product | CPE |
|---|---|---|
| linux | linux kernel | cpe:2.3:o:linux:linux_kernel |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- linux linux kernel4.5 and later · before 5.10.102
- linux linux kernel5.11 and later · before 5.15.25
- linux linux kernel5.16 and later · before 5.16.10
- linux linux kernel5.17
Versions reported by the vendor
Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.
Linux Linux
- 4.5affected
- e9b61f19858a5d6c42ce2298cf138279375d0d9b and later · before db3f3636e4aed2cba3e4e7897a053323f7a62249affected · git
- e9b61f19858a5d6c42ce2298cf138279375d0d9b and later · before a8dd0cfa37792863b6c4bf9542975212a6715d49affected · git
- e9b61f19858a5d6c42ce2298cf138279375d0d9b and later · before 05d3f8045efa59457b323caf00bdb9273b7962faaffected · git
- e9b61f19858a5d6c42ce2298cf138279375d0d9b and later · before 24d7275ce2791829953ed4e72f68277ceb2571c6affected · git
- before 4.5not affected · semver
- 5.10.102 and later · up to and including 5.10.*not affected · semver
- 5.15.25 and later · up to and including 5.15.*not affected · semver
- 5.16.10 and later · up to and including 5.16.*not affected · semver
- 5.17 and laternot affected · original_commit_for_fix
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | linux | before 5.16.10-1 | 5.16.10-1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS | kernel-default-base | before 5.3.18-150200.24.203.1.150200.9.105.1 | 5.3.18-150200.24.203.1.150200.9.105.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS | kernel-docs | before 5.3.18-150200.24.203.1 | 5.3.18-150200.24.203.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS | kernel-obs-build | before 5.3.18-150200.24.203.1 | 5.3.18-150200.24.203.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS | kernel-preempt | before 5.3.18-150200.24.203.1 | 5.3.18-150200.24.203.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS | kernel-source | before 5.3.18-150200.24.203.1 | 5.3.18-150200.24.203.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS | kernel-syms | before 5.3.18-150200.24.203.1 | 5.3.18-150200.24.203.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | kernel-64kb | before 5.3.18-150300.59.174.1 | 5.3.18-150300.59.174.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | kernel-default-base | before 5.3.18-150300.59.174.1.150300.18.103.1 | 5.3.18-150300.59.174.1.150300.18.103.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | kernel-docs | before 5.3.18-150300.59.174.1 | 5.3.18-150300.59.174.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | kernel-obs-build | before 5.3.18-150300.59.174.1 | 5.3.18-150300.59.174.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | kernel-preempt | before 5.3.18-150300.59.174.1 | 5.3.18-150300.59.174.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | kernel-source | before 5.3.18-150300.59.174.1 | 5.3.18-150300.59.174.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | kernel-syms | before 5.3.18-150300.59.174.1 | 5.3.18-150300.59.174.1 |
| SUSE:Linux Enterprise Live Patching 15 SP2 | kernel-default | before 5.3.18-150200.24.203.1 | 5.3.18-150200.24.203.1 |
| SUSE:Linux Enterprise Live Patching 15 SP2 | kernel-livepatch-SLE15-SP2_Update_52 | before 1-150200.5.3.1 | 1-150200.5.3.1 |
| SUSE:Linux Enterprise Live Patching 15 SP3 | kernel-default | before 5.3.18-150300.59.174.1 | 5.3.18-150300.59.174.1 |
| SUSE:Linux Enterprise Live Patching 15 SP3 | kernel-livepatch-SLE15-SP3_Update_48 | before 1-150300.7.3.1 | 1-150300.7.3.1 |
| SUSE:Linux Enterprise Micro 5.1 | kernel-rt | before 5.3.18-150300.181.2 | 5.3.18-150300.181.2 |
| SUSE:Linux Enterprise Micro 5.1 | kernel-source-rt | before 5.3.18-150300.181.2 | 5.3.18-150300.181.2 |
| SUSE:Linux Enterprise Server 15 SP3-LTSS | kernel-zfcpdump | before 5.3.18-150300.59.174.1 | 5.3.18-150300.59.174.1 |
Same product
linux: all recordsOther highest-scoring records for the same primary product.
- CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV89Now
- CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV85Now
- CVE-2016-5195Race condition in mm/gup.c in the Linux kernel 2.x through 4.x before 4.8.3 allows local users to gain privileges by leveraging incorrect haKEV83Now
- CVE-2019-13272In the Linux kernel before 5.1.17, ptrace_link in kernel/ptrace.c mishandles the recording of the credentials of a process that wants to creKEV77This week
- CVE-2013-6282The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the v6k and v7 ARM platforms do not validate certain addKEV77This week
- CVE-2013-2094The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9 uses an incorrect integer data type, which allows loKEV77This week
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Linux Linux | 05d3f8045efa59457b323caf00bdb9273b7962fa | Vendor (CNA) |
| Linux Linux | 24d7275ce2791829953ed4e72f68277ceb2571c6 | Vendor (CNA) |
| Linux Linux | a8dd0cfa37792863b6c4bf9542975212a6715d49 | Vendor (CNA) |
| Linux Linux | db3f3636e4aed2cba3e4e7897a053323f7a62249 | Vendor (CNA) |
| debian:linux | 5.16.10-1 · Debian:12 | Package registry (OSV) |
| suse:kernel-64kb | 5.3.18-150300.59.174.1 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | Package registry (OSV) |
| suse:kernel-default | 5.3.18-150300.59.174.1 · SUSE:Linux Enterprise Live Patching 15 SP3 | Package registry (OSV) |
| suse:kernel-default-base | 5.3.18-150300.59.174.1.150300.18.103.1 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | Package registry (OSV) |
| suse:kernel-docs | 5.3.18-150300.59.174.1 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | Package registry (OSV) |
| suse:kernel-livepatch-SLE15-SP3_Update_48 | 1-150300.7.3.1 · SUSE:Linux Enterprise Live Patching 15 SP3 | Package registry (OSV) |
| suse:kernel-obs-build | 5.3.18-150300.59.174.1 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | Package registry (OSV) |
| suse:kernel-preempt | 5.3.18-150300.59.174.1 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | Package registry (OSV) |
| suse:kernel-rt | 5.3.18-150300.181.2 · SUSE:Linux Enterprise Micro 5.1 | Package registry (OSV) |
| suse:kernel-source | 5.3.18-150300.59.174.1 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | Package registry (OSV) |
| suse:kernel-source-rt | 5.3.18-150300.181.2 · SUSE:Linux Enterprise Micro 5.1 | Package registry (OSV) |
| suse:kernel-syms | 5.3.18-150300.59.174.1 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | Package registry (OSV) |
| suse:kernel-zfcpdump | 5.3.18-150300.59.174.1 · SUSE:Linux Enterprise Server 15 SP3-LTSS | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Someone with local access to the system can trigger it.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
—
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- git.kernel.org/stable/c/05d3f8045efa59457b323caf00bdb9273b7962fa
- git.kernel.org/stable/c/24d7275ce2791829953ed4e72f68277ceb2571c6
- git.kernel.org/stable/c/a8dd0cfa37792863b6c4bf9542975212a6715d49
- git.kernel.org/stable/c/db3f3636e4aed2cba3e4e7897a053323f7a62249
Vendor advisories and official records. Exploit/PoC links are deliberately left out.