From accb61fe7bb0f5c2a4102239e4981650f9048519 Mon Sep 17 00:00:00 2001 From: Jason Baron Date: Fri, 23 Mar 2012 15:02:51 -0700 Subject: coredump: add VM_NODUMP, MADV_NODUMP, MADV_CLEAR_NODUMP Since we no longer need the VM_ALWAYSDUMP flag, let's use the freed bit for 'VM_NODUMP' flag. The idea is is to add a new madvise() flag: MADV_DONTDUMP, which can be set by applications to specifically request memory regions which should not dump core. The specific application I have in mind is qemu: we can add a flag there that wouldn't dump all of guest memory when qemu dumps core. This flag might also be useful for security sensitive apps that want to absolutely make sure that parts of memory are not dumped. To clear the flag use: MADV_DODUMP. [akpm@linux-foundation.org: s/MADV_NODUMP/MADV_DONTDUMP/, s/MADV_CLEAR_NODUMP/MADV_DODUMP/, per Roland] [akpm@linux-foundation.org: fix up the architectures which broke] Signed-off-by: Jason Baron Acked-by: Roland McGrath Cc: Chris Metcalf Cc: Avi Kivity Cc: Ralf Baechle Cc: Richard Henderson Cc: Ivan Kokshaysky Cc: Matt Turner Cc: "James E.J. Bottomley" Cc: Helge Deller Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/madvise.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'mm') diff --git a/mm/madvise.c b/mm/madvise.c index f5ab745672b7..1ccbba5b6674 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -65,6 +65,12 @@ static long madvise_behavior(struct vm_area_struct * vma, } new_flags &= ~VM_DONTCOPY; break; + case MADV_DONTDUMP: + new_flags |= VM_NODUMP; + break; + case MADV_DODUMP: + new_flags &= ~VM_NODUMP; + break; case MADV_MERGEABLE: case MADV_UNMERGEABLE: error = ksm_madvise(vma, start, end, behavior, &new_flags); @@ -293,6 +299,8 @@ madvise_behavior_valid(int behavior) case MADV_HUGEPAGE: case MADV_NOHUGEPAGE: #endif + case MADV_DONTDUMP: + case MADV_DODUMP: return 1; default: -- cgit v1.2.3