{"id":"AZL-64496","summary":"CVE-2025-38102 affecting package kernel for versions less than 6.6.96.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nVMCI: fix race between vmci_host_setup_notify and vmci_ctx_unset_notify\n\nDuring our test, it is found that a warning can be trigger in try_grab_folio\nas follow:\n\n  ------------[ cut here ]------------\n  WARNING: CPU: 0 PID: 1678 at mm/gup.c:147 try_grab_folio+0x106/0x130\n  Modules linked in:\n  CPU: 0 UID: 0 PID: 1678 Comm: syz.3.31 Not tainted 6.15.0-rc5 #163 PREEMPT(undef)\n  RIP: 0010:try_grab_folio+0x106/0x130\n  Call Trace:\n   \u003cTASK\u003e\n   follow_huge_pmd+0x240/0x8e0\n   follow_pmd_mask.constprop.0.isra.0+0x40b/0x5c0\n   follow_pud_mask.constprop.0.isra.0+0x14a/0x170\n   follow_page_mask+0x1c2/0x1f0\n   __get_user_pages+0x176/0x950\n   __gup_longterm_locked+0x15b/0x1060\n   ? gup_fast+0x120/0x1f0\n   gup_fast_fallback+0x17e/0x230\n   get_user_pages_fast+0x5f/0x80\n   vmci_host_unlocked_ioctl+0x21c/0xf80\n  RIP: 0033:0x54d2cd\n  ---[ end trace 0000000000000000 ]---\n\nDigging into the source, context-\u003enotify_page may init by get_user_pages_fast\nand can be seen in vmci_ctx_unset_notify which will try to put_page. However\nget_user_pages_fast is not finished here and lead to following\ntry_grab_folio warning. The race condition is shown as follow:\n\ncpu0\t\t\tcpu1\nvmci_host_do_set_notify\nvmci_host_setup_notify\nget_user_pages_fast(uva, 1, FOLL_WRITE, &context-\u003enotify_page);\nlockless_pages_from_mm\ngup_pgd_range\ngup_huge_pmd  // update &context-\u003enotify_page\n\t\t\tvmci_host_do_set_notify\n\t\t\tvmci_ctx_unset_notify\n\t\t\tnotify_page = context-\u003enotify_page;\n\t\t\tif (notify_page)\n\t\t\tput_page(notify_page);\t// page is freed\n__gup_longterm_locked\n__get_user_pages\nfollow_trans_huge_pmd\ntry_grab_folio // warn here\n\nTo slove this, use local variable page to make notify_page can be seen\nafter finish get_user_pages_fast.","modified":"2026-04-01T05:20:20.590799Z","published":"2025-07-03T09:15:23Z","upstream":["CVE-2025-38102"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-38102"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.6.96.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-64496.json"}}],"schema_version":"1.7.5"}