Matthew Wilcox (Oracle) 2431b5f265 mm: turn folio_test_hugetlb into a PageType ... commit d99e3140a4 upstream. The current folio_test_hugetlb() can be fooled by a concurrent folio split into returning true for a folio which has never belonged to hugetlbfs. This can't happen if the caller holds a refcount on it, but we have a few places (memory-failure, compaction, procfs) which do not and should not take a speculative reference. Since hugetlb pages do not use individual page mapcounts (they are always fully mapped and use the entire_mapcount field to record the number of mappings), the PageType field is available now that page_mapcount() ignores the value in this field. In compaction and with CONFIG_DEBUG_VM enabled, the current implementation can result in an oops, as reported by Luis. This happens since 9c5ccf2db0 ("mm: remove HUGETLB_PAGE_DTOR") effectively added some VM_BUG_ON() checks in the PageHuge() testing path. [willy@infradead.org: update vmcoreinfo] Link: https://lkml.kernel.org/r/ZgGZUvsdhaT1Va-T@casper.infradead.org Link: https://lkml.kernel.org/r/20240321142448.1645400-6-willy@infradead.org Fixes: 9c5ccf2db0 ("mm: remove HUGETLB_PAGE_DTOR") Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Reported-by: Luis Chamberlain <mcgrof@kernel.org> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218227 Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Oscar Salvador <osalvador@suse.de> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2024-05-02 16:32:47 +02:00
..
events	mm: turn folio_test_hugetlb into a PageType	2024-05-02 16:32:47 +02:00
misc
stages	tracing: Error if a trace event has an array for a __field()	2023-04-03 11:52:51 -04:00
bpf_probe.h	kernel.h: split out COUNT_ARGS() and CONCATENATE() to args.h	2023-08-18 10:18:56 -07:00
define_custom_trace.h
define_trace.h
perf.h	perf/tracing: Use stage6 of tracing to not duplicate macros	2023-01-25 10:31:24 -05:00
syscall.h
trace_custom_events.h
trace_events.h