{"id":"CVE-2025-40199","summary":"page_pool: Fix PP_MAGIC_MASK to avoid crashing on some 32-bit arches","details":"In the Linux kernel, the following vulnerability has been resolved:\n\npage_pool: Fix PP_MAGIC_MASK to avoid crashing on some 32-bit arches\n\nHelge reported that the introduction of PP_MAGIC_MASK let to crashes on\nboot on his 32-bit parisc machine. The cause of this is the mask is set\ntoo wide, so the page_pool_page_is_pp() incurs false positives which\ncrashes the machine.\n\nJust disabling the check in page_pool_is_pp() will lead to the page_pool\ncode itself malfunctioning; so instead of doing this, this patch changes\nthe define for PP_DMA_INDEX_BITS to avoid mistaking arbitrary kernel\npointers for page_pool-tagged pages.\n\nThe fix relies on the kernel pointers that alias with the pp_magic field\nalways being above PAGE_OFFSET. With this assumption, we can use the\nlowest bit of the value of PAGE_OFFSET as the upper bound of the\nPP_DMA_INDEX_MASK, which should avoid the false positives.\n\nBecause we cannot rely on PAGE_OFFSET always being a compile-time\nconstant, nor on it always being \u003e0, we fall back to disabling the\ndma_index storage when there are not enough bits available. This leaves\nus in the situation we were in before the patch in the Fixes tag, but\nonly on a subset of architecture configurations. This seems to be the\nbest we can do until the transition to page types in complete for\npage_pool pages.\n\nv2:\n- Make sure there's at least 8 bits available and that the PAGE_OFFSET\n  bit calculation doesn't wrap","modified":"2026-04-02T12:48:19.446637Z","published":"2025-11-12T21:56:33.510Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/40xxx/CVE-2025-40199.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/15b8a5b4cdc16e9a8bb2a548e12a0fd92997605a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/95920c2ed02bde551ab654e9749c2ca7bc3100e0"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f62934cea32c8f7b11b747975d69bf5afe4264cf"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/40xxx/CVE-2025-40199.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-40199"},{"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":"4f51fb0d257ff4d406ec27966902de075e3b118e"},{"fixed":"15b8a5b4cdc16e9a8bb2a548e12a0fd92997605a"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"ee62ce7a1d909ccba0399680a03c2dee83bcae95"},{"fixed":"f62934cea32c8f7b11b747975d69bf5afe4264cf"},{"fixed":"95920c2ed02bde551ab654e9749c2ca7bc3100e0"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"0"},{"last_affected":"c30ae60f41f9edd6e1b5cad41cf28ce04dae39e4"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-40199.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.12.54"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.17.4"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-40199.json"}}],"schema_version":"1.7.5"}