Commit accb61fe authored by Jason Baron's avatar Jason Baron Committed by Linus Torvalds
Browse files

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: default avatarJason Baron <jbaron@redhat.com>
Acked-by: default avatarRoland McGrath <roland@hack.frob.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 909af768

arch/alpha/include/asm/mman.h

+4 −0
Original line number Diff line number Diff line
@@ -56,6 +56,10 @@ 
#define MADV_HUGEPAGE	14		/* Worth backing with hugepages */

#define MADV_NOHUGEPAGE	15		/* Not worth backing with hugepages */



#define MADV_DONTDUMP   16		/* Explicity exclude from the core dump,

					   overrides the coredump filter bits */

#define MADV_DODUMP	17		/* Clear the MADV_NODUMP flag */



/* compatibility flags */

#define MAP_FILE	0

arch/mips/include/asm/mman.h

+4 −0
Original line number Diff line number Diff line
@@ -80,6 +80,10 @@ 
#define MADV_HUGEPAGE	14		/* Worth backing with hugepages */

#define MADV_NOHUGEPAGE	15		/* Not worth backing with hugepages */



#define MADV_DONTDUMP   16		/* Explicity exclude from the core dump,

					   overrides the coredump filter bits */

#define MADV_DODUMP	17		/* Clear the MADV_NODUMP flag */



/* compatibility flags */

#define MAP_FILE	0

arch/parisc/include/asm/mman.h

+4 −0
Original line number Diff line number Diff line
@@ -62,6 +62,10 @@ 
#define MADV_HUGEPAGE	67		/* Worth backing with hugepages */

#define MADV_NOHUGEPAGE	68		/* Not worth backing with hugepages */



#define MADV_DONTDUMP   69		/* Explicity exclude from the core dump,

					   overrides the coredump filter bits */

#define MADV_DODUMP	70		/* Clear the MADV_NODUMP flag */



/* compatibility flags */

#define MAP_FILE	0

#define MAP_VARIABLE	0

arch/xtensa/include/asm/mman.h

+4 −0
Original line number Diff line number Diff line
@@ -86,6 +86,10 @@ 
#define MADV_HUGEPAGE	14		/* Worth backing with hugepages */

#define MADV_NOHUGEPAGE	15		/* Not worth backing with hugepages */



#define MADV_DONTDUMP   16		/* Explicity exclude from the core dump,

					   overrides the coredump filter bits */

#define MADV_DODUMP	17		/* Clear the MADV_NODUMP flag */



/* compatibility flags */

#define MAP_FILE	0

fs/binfmt_elf.c

+3 −0
Original line number Diff line number Diff line
@@ -1127,6 +1127,9 @@ static unsigned long vma_dump_size(struct vm_area_struct *vma, 
	if (always_dump_vma(vma))

		goto whole;



	if (vma->vm_flags & VM_NODUMP)

		return 0;



	/* Hugetlb memory check */

	if (vma->vm_flags & VM_HUGETLB) {

		if ((vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_SHARED))

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