{"id":"CVE-2022-49081","summary":"highmem: fix checks in __kmap_local_sched_{in,out}","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nhighmem: fix checks in __kmap_local_sched_{in,out}\n\nWhen CONFIG_DEBUG_KMAP_LOCAL is enabled __kmap_local_sched_{in,out} check\nthat even slots in the tsk-\u003ekmap_ctrl.pteval are unmapped.  The slots are\ninitialized with 0 value, but the check is done with pte_none.  0 pte\nhowever does not necessarily mean that pte_none will return true.  e.g.\non xtensa it returns false, resulting in the following runtime warnings:\n\n WARNING: CPU: 0 PID: 101 at mm/highmem.c:627 __kmap_local_sched_out+0x51/0x108\n CPU: 0 PID: 101 Comm: touch Not tainted 5.17.0-rc7-00010-gd3a1cdde80d2-dirty #13\n Call Trace:\n   dump_stack+0xc/0x40\n   __warn+0x8f/0x174\n   warn_slowpath_fmt+0x48/0xac\n   __kmap_local_sched_out+0x51/0x108\n   __schedule+0x71a/0x9c4\n   preempt_schedule_irq+0xa0/0xe0\n   common_exception_return+0x5c/0x93\n   do_wp_page+0x30e/0x330\n   handle_mm_fault+0xa70/0xc3c\n   do_page_fault+0x1d8/0x3c4\n   common_exception+0x7f/0x7f\n\n WARNING: CPU: 0 PID: 101 at mm/highmem.c:664 __kmap_local_sched_in+0x50/0xe0\n CPU: 0 PID: 101 Comm: touch Tainted: G        W         5.17.0-rc7-00010-gd3a1cdde80d2-dirty #13\n Call Trace:\n   dump_stack+0xc/0x40\n   __warn+0x8f/0x174\n   warn_slowpath_fmt+0x48/0xac\n   __kmap_local_sched_in+0x50/0xe0\n   finish_task_switch$isra$0+0x1ce/0x2f8\n   __schedule+0x86e/0x9c4\n   preempt_schedule_irq+0xa0/0xe0\n   common_exception_return+0x5c/0x93\n   do_wp_page+0x30e/0x330\n   handle_mm_fault+0xa70/0xc3c\n   do_page_fault+0x1d8/0x3c4\n   common_exception+0x7f/0x7f\n\nFix it by replacing !pte_none(pteval) with pte_val(pteval) != 0.","modified":"2026-04-02T08:27:17.166619Z","published":"2025-02-26T01:54:41.639Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/49xxx/CVE-2022-49081.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/66f133ceab7456c789f70a242991ed1b27ba1c3d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/7dd5b3b97716a611fcf67d92fd2370fcb8d50372"},{"type":"WEB","url":"https://git.kernel.org/stable/c/85550b0f5fa5dd3c30469ea702c44444ef242c83"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c21d040de6225414547d9bd31cd200f290991c85"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/49xxx/CVE-2022-49081.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2022-49081"},{"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":"5fbda3ecd14a5343644979c98d6eb65b7e7de9d8"},{"fixed":"c21d040de6225414547d9bd31cd200f290991c85"},{"fixed":"85550b0f5fa5dd3c30469ea702c44444ef242c83"},{"fixed":"7dd5b3b97716a611fcf67d92fd2370fcb8d50372"},{"fixed":"66f133ceab7456c789f70a242991ed1b27ba1c3d"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2022-49081.json"}}],"schema_version":"1.7.5"}