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Jason Baron 909af768e8 coredump: remove VM_ALWAYSDUMP flag 
The motivation for this patchset was that I was looking at a way for a
qemu-kvm process, to exclude the guest memory from its core dump, which
can be quite large.  There are already a number of filter flags in
/proc/<pid>/coredump_filter, however, these allow one to specify 'types'
of kernel memory, not specific address ranges (which is needed in this
case).

Since there are no more vma flags available, the first patch eliminates
the need for the 'VM_ALWAYSDUMP' flag.  The flag is used internally by
the kernel to mark vdso and vsyscall pages.  However, it is simple
enough to check if a vma covers a vdso or vsyscall page without the need
for this flag.

The second patch then replaces the 'VM_ALWAYSDUMP' flag with a new
'VM_NODUMP' flag, which can be set by userspace using new madvise flags:
'MADV_DONTDUMP', and unset via 'MADV_DODUMP'.  The core dump filters
continue to work the same as before unless 'MADV_DONTDUMP' is set on the
region.

The qemu code which implements this features is at:

  http://people.redhat.com/~jbaron/qemu-dump/qemu-dump.patch

In my testing the qemu core dump shrunk from 383MB -> 13MB with this
patch.

I also believe that the 'MADV_DONTDUMP' flag might be useful for
security sensitive apps, which might want to select which areas are
dumped.

This patch:

The VM_ALWAYSDUMP flag is currently used by the coredump code to
indicate that a vma is part of a vsyscall or vdso section.  However, we
can determine if a vma is in one these sections by checking it against
the gate_vma and checking for a non-NULL return value from
arch_vma_name().  Thus, freeing a valuable vma bit.

Signed-off-by: Jason Baron <jbaron@redhat.com>
Acked-by: Roland McGrath <roland@hack.frob.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Avi Kivity <avi@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-23 16:58:42 -07:00
..
9p 9p: make register_filesystem() the last failure exit 2012-03-20 21:29:45 -04:00
adfs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
affs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
afs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-03-21 13:36:41 -07:00
autofs4 autofs: set things up *before* registering fs type 2012-03-20 21:29:46 -04:00
befs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
bfs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
btrfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-03-21 13:36:41 -07:00
cachefiles switch touch_atime to struct path 2012-03-20 21:29:41 -04:00
ceph switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
cifs Merge git://git.samba.org/sfrench/cifs-2.6 2012-03-23 09:07:15 -07:00
coda switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
configfs make configfs_pin_fs() return root dentry on success 2012-03-20 21:29:48 -04:00
cramfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-03-21 13:36:41 -07:00
debugfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-03-21 13:36:41 -07:00
devpts Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-03-21 13:36:41 -07:00
dlm dlm for 3.4 2012-03-21 13:54:22 -07:00
ecryptfs ecryptfs: make register_filesystem() the last potential failure exit 2012-03-20 21:29:49 -04:00
efs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
exofs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-03-21 13:36:41 -07:00
exportfs
ext2 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-03-21 13:36:41 -07:00
ext3 switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
ext4 ext4: initialization of ext4_li_mtx needs to be done earlier 2012-03-20 22:05:02 -04:00
fat fat: fix bug in enforcing Long File Name length 2012-03-23 16:58:40 -07:00
freevxfs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
fscache
fuse Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-03-21 13:36:41 -07:00
gfs2 Merge git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-3.0-nmw 2012-03-21 18:00:03 -07:00
hfs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
hfsplus hfsplus: add an ioctl to bless files 2012-03-20 21:29:53 -04:00
hostfs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
hpfs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
hppfs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
hugetlbfs Merge branch 'akpm' (Andrew's patch-bomb) 2012-03-22 09:04:48 -07:00
isofs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
jbd Power management updates for 3.4 2012-03-21 10:15:51 -07:00
jbd2 Power management updates for 3.4 2012-03-21 10:15:51 -07:00
jffs2 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-03-21 13:36:41 -07:00
jfs jfs: mising cleanup on register_filesystem() failure 2012-03-20 21:29:48 -04:00
lockd SUNRPC/LOCKD: Fix build warnings when CONFIG_SUNRPC_DEBUG is undefined 2012-03-21 09:31:44 -04:00
logfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-03-21 13:36:41 -07:00
minix Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-03-21 13:36:41 -07:00
ncpfs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
nfs NFS client updates for Linux 3.4 2012-03-23 08:53:47 -07:00
nfs_common
nfsd NFS client updates for Linux 3.4 2012-03-23 08:53:47 -07:00
nilfs2 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-03-21 13:36:41 -07:00
nls NLS: raname "maxlen" to "maxout" in UTF conversion routines 2011-11-26 19:58:47 -08:00
notify fs/notify/notification.c: make subsys_initcall function static 2012-03-23 16:58:31 -07:00
ntfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-03-21 13:36:41 -07:00
ocfs2 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-03-21 13:36:41 -07:00
omfs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
openpromfs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
proc Merge branch 'akpm' (Andrew's patch-bomb) 2012-03-22 09:04:48 -07:00
pstore One pstore patch 2012-03-23 09:24:07 -07:00
qnx4 qnx4: new helper - try_extent() 2012-03-20 21:29:52 -04:00
qnx6 fs: initial qnx6fs addition 2012-03-20 21:29:38 -04:00
quota Merge branch 'for-linus' of git://oss.sgi.com/xfs/xfs 2012-03-23 09:19:22 -07:00
ramfs tidy up after d_make_root() conversion 2012-03-20 21:29:37 -04:00
reiserfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-03-21 13:36:41 -07:00
romfs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
squashfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-03-21 13:36:41 -07:00
sysfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-03-21 13:36:41 -07:00
sysv switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
ubifs - Improve error messages 2012-03-23 09:27:40 -07:00
udf Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-03-21 13:36:41 -07:00
ufs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
xfs Merge branch 'for-linus' of git://oss.sgi.com/xfs/xfs 2012-03-23 09:19:22 -07:00
aio.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-03-21 13:36:41 -07:00
anon_inodes.c anon_inodes: move allocation of anon_inode into ->mount() 2012-03-20 21:29:45 -04:00
attr.c switch is_sxid() to umode_t 2012-01-03 22:55:11 -05:00
bad_inode.c switch ->mknod() to umode_t 2012-01-03 22:54:54 -05:00
binfmt_aout.c take removal of PF_FORKNOEXEC to flush_old_exec() 2012-03-20 21:29:51 -04:00
binfmt_elf.c coredump: remove VM_ALWAYSDUMP flag 2012-03-23 16:58:42 -07:00
binfmt_elf_fdpic.c take removal of PF_FORKNOEXEC to flush_old_exec() 2012-03-20 21:29:51 -04:00
binfmt_em86.c __register_binfmt() made void 2012-03-20 21:29:46 -04:00
binfmt_flat.c take removal of PF_FORKNOEXEC to flush_old_exec() 2012-03-20 21:29:51 -04:00
binfmt_misc.c magic.h: move some FS magic numbers into magic.h 2012-03-23 16:58:31 -07:00
binfmt_script.c __register_binfmt() made void 2012-03-20 21:29:46 -04:00
binfmt_som.c take removal of PF_FORKNOEXEC to flush_old_exec() 2012-03-20 21:29:51 -04:00
bio-integrity.c fs: remove the second argument of k[un]map_atomic() 2012-03-20 21:48:21 +08:00
bio.c bio: don't overflow in bio_get_nr_vecs() 2012-02-08 22:07:18 +01:00
block_dev.c magic.h: move some FS magic numbers into magic.h 2012-03-23 16:58:31 -07:00
buffer.c fs: move code out of buffer.c 2012-01-03 22:54:07 -05:00
char_dev.c char_dev.c: fix up some whitespace errors 2011-12-13 11:18:17 -08:00
compat.c vfs: fix compat_sys_stat() handling of overflows in st_nlink 2012-02-13 20:45:39 -05:00
compat_binfmt_elf.c
compat_ioctl.c ppp: Replace uses of <linux/if_ppp.h> with <linux/ppp-ioctl.h> 2012-03-04 20:41:38 -05:00
dcache.c fs: fix kernel-doc warnings in dcache.c 2012-03-22 15:49:18 -07:00
dcookies.c
direct-io.c Restore direct_io / truncate locking API 2012-02-23 15:56:21 -08:00
drop_caches.c
eventfd.c
eventpoll.c epoll: remove unneeded variable in reverse_path_check() 2012-03-23 16:58:38 -07:00
exec.c Merge branch 'akpm' (Andrew's patch-bomb) 2012-03-22 09:04:48 -07:00
fcntl.c
fhandle.c vfs: prefer ->dentry->d_sb to ->mnt->mnt_sb 2012-01-06 23:16:53 -05:00
fifo.c
file.c vfs: avoid large kmalloc()s for the fdtable 2011-04-28 11:28:20 -07:00
file_table.c vfs: drop_file_write_access() made static 2012-03-20 21:29:32 -04:00
filesystems.c vfs: convert fs_supers to hlist 2012-01-03 22:52:39 -05:00
fs-writeback.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2012-03-20 21:12:50 -07:00
fs_struct.c vfs: take path_get_longterm() out of write_seqcount scope 2012-03-20 21:29:42 -04:00
generic_acl.c switch posix_acl_equiv_mode() to umode_t * 2011-08-01 02:10:06 -04:00
inode.c trim includes in inode.c 2012-03-20 21:29:51 -04:00
internal.h vfs: protect remounting superblock read-only 2012-01-06 23:20:12 -05:00
ioctl.c vfs: fix up ENOIOCTLCMD error handling 2012-01-05 15:40:12 -08:00
ioprio.c block: strip out locking optimization in put_io_context() 2012-02-07 07:51:30 +01:00
Kconfig Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-03-21 13:36:41 -07:00
Kconfig.binfmt fs: binfmt_elf: create Kconfig variable for PIE randomization 2012-01-10 16:30:51 -08:00
libfs.c make simple_pin_fs() pass MS_KERNMOUNT - it's a kernel-internal one 2012-03-20 21:29:44 -04:00
locks.c vfs: fix handling of lock allocation failure in lease-break case 2011-12-26 10:25:26 -08:00
Makefile fs: initial qnx6fs addition 2012-03-20 21:29:38 -04:00
mbcache.c
mount.h vfs: keep list of mounts for each superblock 2012-01-06 23:20:12 -05:00
mpage.c fs: remove unneeded plug in mpage_readpages() 2012-01-12 09:19:54 +01:00
namei.c vfs: tidy up sparse warnings in fs/namei.c 2012-03-22 16:10:40 -07:00
namespace.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2012-01-08 13:21:22 -08:00
no-block.c
open.c switch security_path_chmod() to struct path * 2012-01-06 23:16:53 -05:00
pipe.c magic.h: move some FS magic numbers into magic.h 2012-03-23 16:58:31 -07:00
pnode.c vfs: switch pnode.h macros to struct mount * 2012-01-03 22:57:11 -05:00
pnode.h vfs: switch pnode.h macros to struct mount * 2012-01-03 22:57:11 -05:00
posix_acl.c vfs: pass all mask flags check_acl and posix_acl_permission 2011-10-28 14:58:54 +02:00
proc_namespace.c vfs: switch ->show_options() to struct dentry * 2012-01-06 23:19:54 -05:00
read_write.c
read_write.h
readdir.c
select.c poll: add poll_requested_events() and poll_does_not_wait() functions 2012-03-23 16:58:38 -07:00
seq_file.c seq_file: fix mishandling of consecutive pread() invocations. 2012-03-21 17:54:54 -07:00
signalfd.c epoll: ep_unregister_pollwait() can use the freed pwq->whead 2012-02-24 11:42:50 -08:00
splice.c fs: remove the second argument of k[un]map_atomic() 2012-03-20 21:48:21 +08:00
stack.c
stat.c switch touch_atime to struct path 2012-03-20 21:29:41 -04:00
statfs.c vfs: new helper - vfs_ustat() 2012-01-03 22:53:07 -05:00
super.c Cleanups: rename of flush to invalidate, moving reporting of statistics 2012-03-22 19:52:47 -07:00
sync.c fs: move code out of buffer.c 2012-01-03 22:54:07 -05:00
timerfd.c
utimes.c
xattr.c vfs: mnt_drop_write_file() 2012-01-03 22:52:40 -05:00
xattr_acl.c