{"id":"DEBIAN-CVE-2023-52490","details":"In the Linux kernel, the following vulnerability has been resolved:  mm: migrate: fix getting incorrect page mapping during page migration  When running stress-ng testing, we found below kernel crash after a few hours:  Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 pc : dentry_name+0xd8/0x224 lr : pointer+0x22c/0x370 sp : ffff800025f134c0 ...... Call trace:   dentry_name+0xd8/0x224   pointer+0x22c/0x370   vsnprintf+0x1ec/0x730   vscnprintf+0x2c/0x60   vprintk_store+0x70/0x234   vprintk_emit+0xe0/0x24c   vprintk_default+0x3c/0x44   vprintk_func+0x84/0x2d0   printk+0x64/0x88   __dump_page+0x52c/0x530   dump_page+0x14/0x20   set_migratetype_isolate+0x110/0x224   start_isolate_page_range+0xc4/0x20c   offline_pages+0x124/0x474   memory_block_offline+0x44/0xf4   memory_subsys_offline+0x3c/0x70   device_offline+0xf0/0x120   ......  After analyzing the vmcore, I found this issue is caused by page migration. The scenario is that, one thread is doing page migration, and we will use the target page's -\u003emapping field to save 'anon_vma' pointer between page unmap and page move, and now the target page is locked and refcount is 1.  Currently, there is another stress-ng thread performing memory hotplug, attempting to offline the target page that is being migrated. It discovers that the refcount of this target page is 1, preventing the offline operation, thus proceeding to dump the page. However, page_mapping() of the target page may return an incorrect file mapping to crash the system in dump_mapping(), since the target page-\u003emapping only saves 'anon_vma' pointer without setting PAGE_MAPPING_ANON flag.  There are seveval ways to fix this issue: (1) Setting the PAGE_MAPPING_ANON flag for target page's -\u003emapping when saving 'anon_vma', but this can confuse PageAnon() for PFN walkers, since the target page has not built mappings yet. (2) Getting the page lock to call page_mapping() in __dump_page() to avoid crashing the system, however, there are still some PFN walkers that call page_mapping() without holding the page lock, such as compaction. (3) Using target page-\u003eprivate field to save the 'anon_vma' pointer and 2 bits page state, just as page-\u003emapping records an anonymous page, which can remove the page_mapping() impact for PFN walkers and also seems a simple way.  So I choose option 3 to fix this issue, and this can also fix other potential issues for PFN walkers, such as compaction.","modified":"2026-09-15T09:02:47.790763567Z","published":"2024-03-11T18:15:16.750Z","upstream":["CVE-2023-52490"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2023-52490"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:13","purl":"pkg:deb/debian/linux?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.6.15-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2023-52490.json"}},{"package":{"name":"linux","ecosystem":"Debian:14","purl":"pkg:deb/debian/linux?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.6.15-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2023-52490.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}