{"id":"CVE-2022-48943","summary":"KVM: x86/mmu: make apf token non-zero to fix bug","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: x86/mmu: make apf token non-zero to fix bug\n\nIn current async pagefault logic, when a page is ready, KVM relies on\nkvm_arch_can_dequeue_async_page_present() to determine whether to deliver\na READY event to the Guest. This function test token value of struct\nkvm_vcpu_pv_apf_data, which must be reset to zero by Guest kernel when a\nREADY event is finished by Guest. If value is zero meaning that a READY\nevent is done, so the KVM can deliver another.\nBut the kvm_arch_setup_async_pf() may produce a valid token with zero\nvalue, which is confused with previous mention and may lead the loss of\nthis READY event.\n\nThis bug may cause task blocked forever in Guest:\n INFO: task stress:7532 blocked for more than 1254 seconds.\n       Not tainted 5.10.0 #16\n \"echo 0 \u003e /proc/sys/kernel/hung_task_timeout_secs\" disables this message.\n task:stress          state:D stack:    0 pid: 7532 ppid:  1409\n flags:0x00000080\n Call Trace:\n  __schedule+0x1e7/0x650\n  schedule+0x46/0xb0\n  kvm_async_pf_task_wait_schedule+0xad/0xe0\n  ? exit_to_user_mode_prepare+0x60/0x70\n  __kvm_handle_async_pf+0x4f/0xb0\n  ? asm_exc_page_fault+0x8/0x30\n  exc_page_fault+0x6f/0x110\n  ? asm_exc_page_fault+0x8/0x30\n  asm_exc_page_fault+0x1e/0x30\n RIP: 0033:0x402d00\n RSP: 002b:00007ffd31912500 EFLAGS: 00010206\n RAX: 0000000000071000 RBX: ffffffffffffffff RCX: 00000000021a32b0\n RDX: 000000000007d011 RSI: 000000000007d000 RDI: 00000000021262b0\n RBP: 00000000021262b0 R08: 0000000000000003 R09: 0000000000000086\n R10: 00000000000000eb R11: 00007fefbdf2baa0 R12: 0000000000000000\n R13: 0000000000000002 R14: 000000000007d000 R15: 0000000000001000","modified":"2026-04-02T08:27:09.761958Z","published":"2024-08-22T03:30:14.027Z","related":["SUSE-SU-2024:3190-1","SUSE-SU-2024:3209-1","SUSE-SU-2024:3227-1","SUSE-SU-2024:3408-1","SUSE-SU-2024:3483-1","SUSE-SU-2024:3559-1","SUSE-SU-2024:3566-1","SUSE-SU-2024:3591-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/48xxx/CVE-2022-48943.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/4c3644b6c96c5daa5149e5abddc07234eea47c7c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/62040f5cd7d937de547836e747b6aa8212fec573"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6f3c1fc53d86d580d8d6d749c4af23705e4f6f79"},{"type":"WEB","url":"https://git.kernel.org/stable/c/72fdfc75d4217b32363cc80def3de2cb3fef3f02"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/48xxx/CVE-2022-48943.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2022-48943"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"2635b5c4a0e407b84f68e188c719f28ba0e9ae1b"},{"fixed":"72fdfc75d4217b32363cc80def3de2cb3fef3f02"},{"fixed":"4c3644b6c96c5daa5149e5abddc07234eea47c7c"},{"fixed":"62040f5cd7d937de547836e747b6aa8212fec573"},{"fixed":"6f3c1fc53d86d580d8d6d749c4af23705e4f6f79"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2022-48943.json"}}],"schema_version":"1.7.5"}