{"id":"AZL-55172","summary":"CVE-2024-56613 affecting package kernel for versions less than 6.6.76.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched/numa: fix memory leak due to the overwritten vma-\u003enumab_state\n\n[Problem Description]\nWhen running the hackbench program of LTP, the following memory leak is\nreported by kmemleak.\n\n  # /opt/ltp/testcases/bin/hackbench 20 thread 1000\n  Running with 20*40 (== 800) tasks.\n\n  # dmesg | grep kmemleak\n  ...\n  kmemleak: 480 new suspected memory leaks (see /sys/kernel/debug/kmemleak)\n  kmemleak: 665 new suspected memory leaks (see /sys/kernel/debug/kmemleak)\n\n  # cat /sys/kernel/debug/kmemleak\n  unreferenced object 0xffff888cd8ca2c40 (size 64):\n    comm \"hackbench\", pid 17142, jiffies 4299780315\n    hex dump (first 32 bytes):\n      ac 74 49 00 01 00 00 00 4c 84 49 00 01 00 00 00  .tI.....L.I.....\n      00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................\n    backtrace (crc bff18fd4):\n      [\u003cffffffff81419a89\u003e] __kmalloc_cache_noprof+0x2f9/0x3f0\n      [\u003cffffffff8113f715\u003e] task_numa_work+0x725/0xa00\n      [\u003cffffffff8110f878\u003e] task_work_run+0x58/0x90\n      [\u003cffffffff81ddd9f8\u003e] syscall_exit_to_user_mode+0x1c8/0x1e0\n      [\u003cffffffff81dd78d5\u003e] do_syscall_64+0x85/0x150\n      [\u003cffffffff81e0012b\u003e] entry_SYSCALL_64_after_hwframe+0x76/0x7e\n  ...\n\nThis issue can be consistently reproduced on three different servers:\n  * a 448-core server\n  * a 256-core server\n  * a 192-core server\n\n[Root Cause]\nSince multiple threads are created by the hackbench program (along with\nthe command argument 'thread'), a shared vma might be accessed by two or\nmore cores simultaneously. When two or more cores observe that\nvma-\u003enumab_state is NULL at the same time, vma-\u003enumab_state will be\noverwritten.\n\nAlthough current code ensures that only one thread scans the VMAs in a\nsingle 'numa_scan_period', there might be a chance for another thread\nto enter in the next 'numa_scan_period' while we have not gotten till\nnumab_state allocation [1].\n\nNote that the command `/opt/ltp/testcases/bin/hackbench 50 process 1000`\ncannot the reproduce the issue. It is verified with 200+ test runs.\n\n[Solution]\nUse the cmpxchg atomic operation to ensure that only one thread executes\nthe vma-\u003enumab_state assignment.\n\n[1] https://lore.kernel.org/lkml/1794be3c-358c-4cdc-a43d-a1f841d91ef7@amd.com/","modified":"2026-04-01T05:18:31.294134Z","published":"2024-12-27T15:15:20Z","upstream":["CVE-2024-56613"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-56613"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.6.76.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-55172.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}