To avoid potential problems with an empty /dev open /dev/console
from rootfs instead of waiting to mount our root filesystem and
mounting it there. This effectively guarantees that there will
be a device node, and it won't be on a filesystem that we will
ever unmount, so there are no issues with leaving /dev/console
open and pinning the filesystem.
This is actually more effective than automatically mounting
devtmpfs on /dev because it removes removes the occasionally
problematic assumption that /dev/console exists from the boot
code.
With this patch I was able to throw busybox on my /boot partition
(which has no /dev directory) and boot into userspace without
problems.
The only possible negative consequence I can think of is that
someone out there deliberately used did not use a character device
that is major 5 minor 2 for /dev/console. Does anyone know of a
situation in which that could make sense?
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
It reduces code size:
text data bss dec hex filename
9925 72 16 10013 271d ipc/mqueue-BEFORE.o
9885 72 16 9973 26f5 ipc/mqueue-AFTER.o
Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Code size reduction:
text data bss dec hex filename
9941 72 16 10029 272d ipc/mqueue-BEFORE.o
9925 72 16 10013 271d ipc/mqueue-AFTER.o
Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
... and abort earlier if we couldn't allocate the message pointers array,
avoiding the u->mq_bytes accounting logic.
It reduces code size:
text data bss dec hex filename
9949 72 16 10037 2735 ipc/mqueue-BEFORE.o
9941 72 16 10029 272d ipc/mqueue-AFTER.o
Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
rehashing the negative placeholder opens a race with d_lookup();
we unhash it almost immediately (by d_move()), but the race
window is there. Since d_move() doesn't rely on target being
hashed, we don't need that d_rehash() at all.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Add a new UMOUNT_NOFOLLOW flag to umount(2). This is needed to prevent
symlink attacks in unprivileged unmounts (fuse, samba, ncpfs).
Additionally, return -EINVAL if an unknown flag is used (and specify
an explicitly unused flag: UMOUNT_UNUSED). This makes it possible for
the caller to determine if a flag is supported or not.
CC: Eugene Teo <eugene@redhat.com>
CC: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
It hadn't been needed since we'd sanitized the logics in
mark_mounts_for_expiry() (which, in turn, used to be a
rudiment of bad old times when namespace_sem was per-ns).
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
passing *any* namespace root to __d_path() as root is equivalent
to just passing it {NULL, NULL}; no need to bother with finding
the root of our namespace in there.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
