diff options
| author | Atsushi Kumagai <ats-kumagai@wm.jp.nec.com> | 2016-04-28 16:18:21 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-04-28 19:34:04 -0700 |
| commit | d7f53518f713d3d9bf5ed150f943853fb94e7473 (patch) | |
| tree | 4fdd506ffcbf64fb211c70e8bce92c251af903cf | |
| parent | 8639a847b0e11f8d2daa3eafe15a9609c91fd357 (diff) | |
kexec: export OFFSET(page.compound_head) to find out compound tail page
PageAnon() always look at head page to check PAGE_MAPPING_ANON and tail
page's page->mapping has just a poisoned data since commit 1c290f642101
("mm: sanitize page->mapping for tail pages").
If makedumpfile checks page->mapping of a compound tail page to
distinguish anonymous page as usual, it must fail in newer kernel. So
it's necessary to export OFFSET(page.compound_head) to avoid checking
compound tail pages.
The problem is that unnecessary hugepages won't be removed from a dump
file in kernels 4.5.x and later. This means that extra disk space would
be consumed. It's a problem, but not critical.
Signed-off-by: Atsushi Kumagai <ats-kumagai@wm.jp.nec.com>
Acked-by: Dave Young <dyoung@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | kernel/kexec_core.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c index cbbb4c724149..1391d3ee3b86 100644 --- a/kernel/kexec_core.c +++ b/kernel/kexec_core.c @@ -1417,6 +1417,7 @@ static int __init crash_save_vmcoreinfo_init(void) VMCOREINFO_OFFSET(page, private); VMCOREINFO_OFFSET(page, compound_dtor); VMCOREINFO_OFFSET(page, compound_order); + VMCOREINFO_OFFSET(page, compound_head); VMCOREINFO_OFFSET(pglist_data, node_zones); VMCOREINFO_OFFSET(pglist_data, nr_zones); #ifdef CONFIG_FLAT_NODE_MEM_MAP |