# CVE-2022-50517: linux: In the Linux kernel, the following vulnerability has been resolved:  mm/huge_memory: do not clobber swp_entry_t durin...

CVE-2022-50517 is fixed in linux on 1 platform, first by DEBIAN-CVE-2022-50517, released October 7, 2025. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2022-50517
- Priority: Routine
- CVSS: 5.5 (medium)
- EPSS: 0.0015
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 7, 2025

## Description

In the Linux kernel, the following vulnerability has been resolved:  mm/huge_memory: do not clobber swp_entry_t during THP split  The following has been observed when running stressng mmap since commit b653db77350c ("mm: Clear page->private when splitting or migrating a page")     watchdog: BUG: soft lockup - CPU#75 stuck for 26s! [stress-ng:9546]    CPU: 75 PID: 9546 Comm: stress-ng Tainted: G            E      6.0.0-revert-b653db77-fix+ #29 0357d79b60fb09775f678e4f3f64ef0579ad1374    Hardware name: SGI.COM C2112-4GP3/X10DRT-P-Series, BIOS 2.0a 05/09/2016    RIP: 0010:xas_descend+0x28/0x80    Code: cc cc 0f b6 0e 48 8b 57 08 48 d3 ea 83 e2 3f 89 d0 48 83 c0 04 48 8b 44 c6 08 48 89 77 18 48 89 c1 83 e1 03 48 83 f9 02 75 08 <48> 3d fd 00 00 00 76 08 88 57 12 c3 cc cc cc cc 48 c1 e8 02 89 c2    RSP: 0018:ffffbbf02a2236a8 EFLAGS: 00000246    RAX: ffff9cab7d6a0002 RBX: ffffe04b0af88040 RCX: 0000000000000002    RDX: 0000000000000030 RSI: ffff9cab60509b60 RDI: ffffbbf02a2236c0    RBP: 0000000000000000 R08: ffff9cab60509b60 R09: ffffbbf02a2236c0    R10: 0000000000000001 R11: ffffbbf02a223698 R12: 0000000000000000    R13: ffff9cab4e28da80 R14: 0000000000039c01 R15: ffff9cab4e28da88    FS:  00007fab89b85e40(0000) GS:ffff9cea3fcc0000(0000) knlGS:0000000000000000    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033    CR2: 00007fab84e00000 CR3: 00000040b73a4003 CR4: 00000000003706e0    DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000    DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400    Call Trace:     <TASK>     xas_load+0x3a/0x50     __filemap_get_folio+0x80/0x370     ? put_swap_page+0x163/0x360     pagecache_get_page+0x13/0x90     __try_to_reclaim_swap+0x50/0x190     scan_swap_map_slots+0x31e/0x670     get_swap_pages+0x226/0x3c0     folio_alloc_swap+0x1cc/0x240     add_to_swap+0x14/0x70     shrink_page_list+0x968/0xbc0     reclaim_page_list+0x70/0xf0     reclaim_pages+0xdd/0x120     madvise_cold_or_pageout_pte_range+0x814/0xf30     walk_pgd_range+0x637/0xa30     __walk_page_range+0x142/0x170     walk_page_range+0x146/0x170     madvise_pageout+0xb7/0x280     ? asm_common_interrupt+0x22/0x40     madvise_vma_behavior+0x3b7/0xac0     ? find_vma+0x4a/0x70     ? find_vma+0x64/0x70     ? madvise_vma_anon_name+0x40/0x40     madvise_walk_vmas+0xa6/0x130     do_madvise+0x2f4/0x360     __x64_sys_madvise+0x26/0x30     do_syscall_64+0x5b/0x80     ? do_syscall_64+0x67/0x80     ? syscall_exit_to_user_mode+0x17/0x40     ? do_syscall_64+0x67/0x80     ? syscall_exit_to_user_mode+0x17/0x40     ? do_syscall_64+0x67/0x80     ? do_syscall_64+0x67/0x80     ? common_interrupt+0x8b/0xa0     entry_SYSCALL_64_after_hwframe+0x63/0xcd  The problem can be reproduced with the mmtests config config-workload-stressng-mmap.  It does not always happen and when it triggers is variable but it has happened on multiple machines.  The intent of commit b653db77350c patch was to avoid the case where PG_private is clear but folio->private is not-NULL.  However, THP tail pages uses page->private for "swp_entry_t if folio_test_swapcache()" as stated in the documentation for struct folio.  This patch only clobbers page->private for tail pages if the head page was not in swapcache and warns once if page->private had an unexpected value.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.0.7-1 | [DEBIAN-CVE-2022-50517](https://patchblox.com/security/data/fix/linux/debian-cve-2022-50517.md) | Oct 7, 2025 |
| Linux | linux Debian 13.5 (trixie) | 6.0.7-1 | [DEBIAN-CVE-2022-50517](https://patchblox.com/security/data/fix/linux/debian-cve-2022-50517.md) | Oct 7, 2025 |
| Linux | linux Debian 14 | 6.0.7-1 | [DEBIAN-CVE-2022-50517](https://patchblox.com/security/data/fix/linux/debian-cve-2022-50517.md) | Oct 7, 2025 |

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