This change makes __exclude_unnecessary_pages() more robust by verifying that the order of a free page is valid before computing the size of its memory block in the buddy system. The order of a free page cannot be larger than (MAX_ORDER - 1) because the array 'zone.free_area' is of size MAX_ORDER. This situation is reproducible with some s390x dumps: __exclude_unnecessary_pages: Invalid free page order: pfn=2690c0, order=52, max order=8 References: - https://listman.redhat.com/archives/crash-utility/2021-September/009204.html - https://www.kernel.org/doc/gorman/html/understand/understand009.html Signed-off-by: Alexander Egorenkov <egorenar@xxxxxxxxxxxxx> --- makedumpfile.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/makedumpfile.c b/makedumpfile.c index 2ef345879524..56aa026e7b34 100644 --- a/makedumpfile.c +++ b/makedumpfile.c @@ -6457,6 +6457,12 @@ __exclude_unnecessary_pages(unsigned long mem_map, else if ((info->dump_level & DL_EXCLUDE_FREE) && info->page_is_buddy && info->page_is_buddy(flags, _mapcount, private, _count)) { + if (private >= ARRAY_LENGTH(zone.free_area)) { + ERRMSG("Invalid free page order: pfn=%llx, order=%lu, max order=%lu\n", + pfn, private, ARRAY_LENGTH(zone.free_area) - 1); + free(page_cache); + return FALSE; + } nr_pages = 1 << private; pfn_counter = &pfn_free; } -- 2.34.1 _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
