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 <egore...@linux.ibm.com> --- makedumpfile.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/makedumpfile.c b/makedumpfile.c index ca4b0f1cb58f..56aa026e7b34 100644 --- a/makedumpfile.c +++ b/makedumpfile.c @@ -6457,9 +6457,11 @@ __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 > 11) { - ERRMSG("Invalid buddy page order: pfn=%llx, _mapcount=%x, _count=%x, private=%lx\n", pfn, _mapcount, _count, private); - abort(); + 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@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
