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CVE Record

CVE-2023-54165: zsmalloc: move LRU update from zs_map_object() to zs_malloc()

In the Linux kernel, the following vulnerability has been resolved: zsmalloc: move LRU update from zs_map_object() to zs_malloc() Under memory pressure, we sometimes observe the following crash: [ 5694.832838] ------------[ cut here ]------------ [ 5694.842093] list_del corruption, ffff888014b6a448->next is LIST_POISON1 (dead000000000100) [ 5694.858677] WARNING: CPU: 33 PID: 418824 at lib/list_debug.c:47 __list_del_entry_valid+0x42/0x80 [ 5694.961820] CPU: 33 PID: 418824 Comm: fuse_counters.s Kdump: loaded Tainted: G S 5.19.0-0_fbk3_rc3_hoangnhatpzsdynshrv41_10870_g85a9558a25de #1 [ 5694.990194] Hardware name: Wiwynn Twin Lakes MP/Twin Lakes Passive MP, BIOS YMM16 05/24/2021 [ 5695.007072] RIP: 0010:__list_del_entry_valid+0x42/0x80 [ 5695.017351] Code: 08 48 83 c2 22 48 39 d0 74 24 48 8b 10 48 39 f2 75 2c 48 8b 51 08 b0 01 48 39 f2 75 34 c3 48 c7 c7 55 d7 78 82 e8 4e 45 3b 00 <0f> 0b eb 31 48 c7 c7 27 a8 70 82 e8 3e 45 3b 00 0f 0b eb 21 48 c7 [ 5695.054919] RSP: 0018:ffffc90027aef4f0 EFLAGS: 00010246 [ 5695.065366] RAX: 41fe484987275300 RBX: ffff888008988180 RCX: 0000000000000000 [ 5695.079636] RDX: ffff88886006c280 RSI: ffff888860060480 RDI: ffff888860060480 [ 5695.093904] RBP: 0000000000000002 R08: 0000000000000000 R09: ffffc90027aef370 [ 5695.108175] R10: 0000000000000000 R11: ffffffff82fdf1c0 R12: 0000000010000002 [ 5695.122447] R13: ffff888014b6a448 R14: ffff888014b6a420 R15: 00000000138dc240 [ 5695.136717] FS: 00007f23a7d3f740(0000) GS:ffff888860040000(0000) knlGS:0000000000000000 [ 5695.152899] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 5695.164388] CR2: 0000560ceaab6ac0 CR3: 000000001c06c001 CR4: 00000000007706e0 [ 5695.178659] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 5695.192927] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 5695.207197] PKRU: 55555554 [ 5695.212602] Call Trace: [ 5695.217486] <TASK> [ 5695.221674] zs_map_object+0x91/0x270 [ 5695.229000] zswap_frontswap_store+0x33d/0x870 [ 5695.237885] ? do_raw_spin_lock+0x5d/0xa0 [ 5695.245899] __frontswap_store+0x51/0xb0 [ 5695.253742] swap_writepage+0x3c/0x60 [ 5695.261063] shrink_page_list+0x738/0x1230 [ 5695.269255] shrink_lruvec+0x5ec/0xcd0 [ 5695.276749] ? shrink_slab+0x187/0x5f0 [ 5695.284240] ? mem_cgroup_iter+0x6e/0x120 [ 5695.292255] shrink_node+0x293/0x7b0 [ 5695.299402] do_try_to_free_pages+0xea/0x550 [ 5695.307940] try_to_free_pages+0x19a/0x490 [ 5695.316126] __folio_alloc+0x19ff/0x3e40 [ 5695.323971] ? __filemap_get_folio+0x8a/0x4e0 [ 5695.332681] ? walk_component+0x2a8/0xb50 [ 5695.340697] ? generic_permission+0xda/0x2a0 [ 5695.349231] ? __filemap_get_folio+0x8a/0x4e0 [ 5695.357940] ? walk_component+0x2a8/0xb50 [ 5695.365955] vma_alloc_folio+0x10e/0x570 [ 5695.373796] ? walk_component+0x52/0xb50 [ 5695.381634] wp_page_copy+0x38c/0xc10 [ 5695.388953] ? filename_lookup+0x378/0xbc0 [ 5695.397140] handle_mm_fault+0x87f/0x1800 [ 5695.405157] do_user_addr_fault+0x1bd/0x570 [ 5695.413520] exc_page_fault+0x5d/0x110 [ 5695.421017] asm_exc_page_fault+0x22/0x30 After some investigation, I have found the following issue: unlike other zswap backends, zsmalloc performs the LRU list update at the object mapping time, rather than when the slot for the object is allocated. This deviation was discussed and agreed upon during the review process of the zsmalloc writeback patch series: https://lore.kernel.org/lkml/Y3flcAXNxxrvy3ZH@cmpxchg.org/ Unfortunately, this introduces a subtle bug that occurs when there is a concurrent store and reclaim, which interleave as follows: zswap_frontswap_store() shrink_worker() zs_malloc() zs_zpool_shrink() spin_lock(&pool->lock) zs_reclaim_page() zspage = find_get_zspage() spin_unlock(&pool->lock) spin_lock(&pool->lock) zspage = list_first_entry(&pool->lru) ---truncated---

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This Linux kernel issue can crash systems under memory pressure when zswap uses zsmalloc. The source describes list corruption during concurrent storage and reclaim activity. The public bundle does not provide CVSS, CWE, or evidence of active exploitation, so business risk depends on where affected kernels and configurations are deployed.

Executive priority

Treat this as a stability and availability issue until vendor severity data is available. Prioritize servers where memory pressure or swap activity can affect production workloads, especially shared platforms where an unexpected kernel crash has broad operational impact.

Technical view

The flaw is in zsmalloc LRU handling. Updating the LRU during zs_map_object(), rather than allocation, allowed a race between zswap_frontswap_store() and shrink_worker() reclaim. The resolved change moves the LRU update to zs_malloc(), addressing list corruption observed as a kernel warning/crash under memory pressure.

Likely exposure

Linux systems running affected kernel builds with zswap/zsmalloc paths are the most relevant exposure. The bundle lists Linux kernel versions including 6.2, 6.3.5, and 6.4 metadata, but exact distro package exposure needs vendor confirmation because backports may differ.

Exploitation context

No cited source in the bundle reports active exploitation, and KEV is false. The described impact is a concurrency-triggered kernel crash under memory pressure, not a documented remote compromise path. Evidence is incomplete for exploitability beyond the crash condition.

Researcher notes

The source evidence supports a race in zsmalloc LRU accounting tied to zswap reclaim. The bundle lacks CVSS, CWE, exploit reports, and full affected-version semantics. Avoid overclaiming privilege escalation or remote attackability without additional vendor analysis.

Mitigation direction

  • Check Linux distribution advisories for fixed kernel packages containing the referenced stable commits.
  • Prioritize kernel updates on systems using zswap or operating under sustained memory pressure.
  • If immediate patching is unavailable, monitor vendor guidance for supported temporary mitigations.
  • Track affected kernel inventory by exact build, not upstream version alone.

Validation and detection

  • Identify systems running Linux kernels matching the affected source-bundle entries.
  • Check whether deployed kernels include commits e95adf7486f2 or d461aac924b9.
  • Review kernel logs for zsmalloc, zswap, list_del corruption, or related memory-pressure crashes.
  • Confirm vendor packages include the upstream stable fix or an equivalent backport.
Prepared
Confidence
medium
Sources
4

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2023-54165 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
3Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

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Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux64f768c6b32e1957e2b65b70e97cb4cb62344bc4, 64f768c6b32e1957e2b65b70e97cb4cb62344bc4unaffected
LinuxLinux6.2, 0, 6.3.5, 6.4affected
Weakness

CWE details

No CWE listed

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