We need to keep some state for a pending asynchronous lock request, so this
patch adds that state to struct nlm_block.
This also adds a function which defers the request, by calling
rqstp->rq_chandle.defer and storing the resulting deferred request in a
nlm_block structure which we insert into lockd's global block list. That
new function isn't called yet, so it's dead code until a later patch.
Signed-off-by: Marc Eshel <eshel@almaden.ibm.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Acquiring a lock on a cluster filesystem may require communication with
remote hosts, and to avoid blocking lockd or nfsd threads during such
communication, we allow the results to be returned asynchronously.
When a ->lock() call needs to block, the file system will return
-EINPROGRESS, and then later return the results with a call to the
routine in the fl_grant field of the lock_manager_operations struct.
This differs from the case when ->lock returns -EAGAIN to a blocking
lock request; in that case, the filesystem calls fl_notify when the lock
is granted, and the caller retries the original lock. So while
fl_notify is merely a hint to the caller that it should retry, fl_grant
actually communicates the final result of the lock operation (with the
lock already acquired in the succesful case).
Therefore fl_grant takes a lock, a status and, for the test lock case, a
conflicting lock. We also allow fl_grant to return an error to the
filesystem, to handle the case where the fl_grant requests arrives after
the lock manager has already given up waiting for it.
Signed-off-by: Marc Eshel <eshel@almaden.ibm.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Convert NFSv4 to the new lock interface. We don't define any callback for now,
so we're not taking advantage of the asynchronous feature--that's less critical
for the multi-threaded nfsd then it is for the single-threaded lockd. But this
does allow a cluster filesystems to export cluster-coherent locking to NFS.
Note that it's cluster filesystems that are the issue--of the filesystems that
define lock methods (nfs, cifs, etc.), most are not exportable by nfsd.
Signed-off-by: Marc Eshel <eshel@almaden.ibm.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Lock managers need to be able to cancel pending lock requests. In the case
where the exported filesystem manages its own locks, it's not sufficient just
to call posix_unblock_lock(); we need to let the filesystem know what's
happening too.
We do this by adding a new fcntl lock command: FL_CANCELLK. Some day this
might also be made available to userspace applications that could benefit from
an asynchronous locking api.
Signed-off-by: Marc Eshel <eshel@almaden.ibm.com>
Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
The nfsv4 protocol's lock operation, in the case of a conflict, returns
information about the conflicting lock.
It's unclear how clients can use this, so for now we're not going so far as to
add a filesystem method that can return a conflicting lock, but we may as well
return something in the local case when it's easy to.
Signed-off-by: Marc Eshel <eshel@almaden.ibm.com>
Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
Factor out the code that switches between generic and filesystem-specific lock
methods; eventually we want to call this from lock managers (lockd and nfsd)
too; currently they only call the generic methods.
This patch does that for all the setlk code.
Signed-off-by: Marc Eshel <eshel@almaden.ibm.com>
Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
Factor out the code that switches between generic and filesystem-specific lock
methods; eventually we want to call this from lock managers (lockd and nfsd)
too; currently they only call the generic methods.
This patch does that for test_lock.
Note that this hasn't been necessary until recently, because the few
filesystems that define ->lock() (nfs, cifs...) aren't exportable via NFS.
However GFS (and, in the future, other cluster filesystems) need to implement
their own locking to get cluster-coherent locking, and also want to be able to
export locking to NFS (lockd and NFSv4).
So we accomplish this by factoring out code such as this and exporting it for
the use of lockd and nfsd.
Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
posix_test_lock() and ->lock() do the same job but have gratuitously
different interfaces. Modify posix_test_lock() so the two agree,
simplifying some code in the process.
Signed-off-by: Marc Eshel <eshel@almaden.ibm.com>
Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
The file_lock argument to ->lock is used to return the conflicting lock
when found. There's no reason for the filesystem to return any private
information with this conflicting lock, but nfsv4 is.
Fix nfsv4 client, and modify locks.c to stop calling fl_release_private
for it in this case.
Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
Cc: "Trond Myklebust" <Trond.Myklebust@netapp.com>"
Factor out a bit of messy code by creating posix-to-flock counterparts
to the existing flock-to-posix helper functions.
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
We must remove the request from whatever list it is currently on before we
can add it to the dirty list.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If the writebacks are cancelled via nfs_cancel_dirty_list, or due to the
memory allocation failing in nfs_flush_one/nfs_flush_multi, then we must
ensure that the PG_writeback flag is cleared.
Also ensure that we actually own the PG_writeback flag whenever we
schedule a new writeback by making nfs_set_page_writeback() return the
value of test_set_page_writeback().
The PG_writeback page flag ends up replacing the functionality of the
PG_FLUSHING nfs_page flag, so we rip that out too.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Do not flag an error if the COMMIT call fails and we decide to resend the
writes. Let the resend flag the error if it fails.
If a write has failed, then nfs_direct_write_result should not attempt to
send a commit. It should just exit asap and return the error to the user.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It looks like nfs_setattr() and nfs_rename() also need to test whether the
target is a regular file before calling nfs_wb_all()...
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit f50b6f8691 introduced a race in
autofs4 between autofs_lookup_unhashed() and autofs_dentry_release().
autofs_dentry_release() ends up clearing the ->dentry and ->inode members
of autofs_info before removing it from the rehash list. The list is
protected by the rehash lock in both functions, but since
autofs_dentry_release() starts tearing the autofs_info struct down before
removing it from the list, autofs_lookup_unhashed() can get a autofs_info
with a NULL dentry.
This patch moves the clearing of ->dentry and ->inode after the removal
from the rehash list.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Acked-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch fixes a bug in function decrementing a key of stat data item.
Offset of reiserfs keys are compared as signed values. To set key offset
to maximal possible value maximal signed value has to be used.
This bug is responsible for severe reiserfs filesystem corruption which
shows itself as warning vs-13060. reiserfsck fixes this corruption by
filesystem tree rebuilding.
Signed-off-by: Vladimir Saveliev <vs@namesys.com>
Cc: <reiserfs-dev@namesys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If rootmode isn't valid, we hit the BUG() in fuse_init_inode. Now
EINVAL is returned.
Signed-off-by: Timo Savola <tsavola@movial.fi>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Revert all this. It can cause device-mapper to receive a different major from
earlier kernels and it turns out that the Amanda backup program (via GNU tar,
apparently) checks major numbers on files when performing incremental backups.
Which is a bit broken of Amanda (or tar), but this feature isn't important
enough to justify the churn.
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Revert e92a4d595b.
Dmitry points out
"When we block_prepare_write() failed while ext3_prepare_write() we jump to
"failure" label and call ext3_prepare_failure() witch search last mapped bh
and invoke commit_write untill it. This is wrong!! because some bh from
begining to the last mapped bh may be not uptodate. As a result we commit to
disk not uptodate page content witch contains garbage from previous usage."
and
"Unexpected file size increasing."
Call trace the same as it was in first issue but result is different.
For example we have file with i_size is zero. we want write two blocks ,
but fs has only one free block.
->ext3_prepare_write(...from == 0, to == 2048)
retry:
->block_prepare_write() == -ENOSPC# we failed but allocated one block here.
->ext3_prepare_failure()
->commit_write( from == 0, to == 1024) # after this i_size becomes 1024 :)
if (ret == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
goto retry;
Finally when all retries will be spended ext3_prepare_failure return
-ENOSPC, but i_size was increased and later block trimm procedures can't
help here.
We don't appear to have the horsepower to fix these issues, so let's put
things back the way they were for now.
Cc: Kirill Korotaev <dev@openvz.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Ken Chen <kenneth.w.chen@intel.com>
Cc: Andrey Savochkin <saw@sw.ru>
Cc: <linux-ext4@vger.kernel.org>
Cc: Dmitriy Monakhov <dmonakhov@openvz.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When the dump cannot occur most likely because of a full file system and
the page to be written is the zero page, the call to page_cache_release()
is missed.
Signed-off-by: Brian Pomerantz <bapper@mvista.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: David Howells <dhowells@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We're using #ifdef CONFIG_SYSCTL, but we should be using CONFIG_PROC_SYSCTL,
so we get
fs/built-in.o: In function `proc_root_init':
/usr/src/linux/fs/proc/root.c:83: undefined reference to `proc_sys_init'
Fix that up and remove an ifdef-in-C.
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Helge Hafting <helgehaf@aitel.hist.no>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* rename name to host_root_path
* rename data to req_root.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix a few miscellaneous compilation problems -
an assignment with mismatched types in ldt.c
a missing include in mconsole.h which needs a definition of uml_pt_regs
I missed removing an include of user_util.h in hostfs
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently if partial write has happened while ->commit_write() then page
wasn't marked as accessed and rebalanced.
Signed-off-by: Monakhov Dmitriy <dmonakhov@openvz.org>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
The user can generate console output if they cause do_mmap() to fail
during sys_io_setup(). This was seen in a regression test that does
exactly that by spinning calling mmap() until it gets -ENOMEM before
calling io_setup().
We don't need this printk at all, just remove it.
Signed-off-by: Zach Brown <zach.brown@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Johannes Berg and Michael Buesch noticed that the WPA ioctls
were missing from the 64<->32 bit conversion. This means that when
using a 32 bits userspace on a 64 bit kernel, those ioctls fail.
Signed-off-by: Jean Tourrilhes <jt@hpl.hp.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
* 'for-linus' of git://git.kernel.dk/data/git/linux-2.6-block:
Export __splice_from_pipe()
2/2 splice: dont readpage
1/2 splice: dont steal
make elv_register() output atomic
block: blk_max_pfn is somtimes wrong
Without attached patch against current -git I get following with
!PROC_SYSCTL (with EMBEDDED and PROC_FS set):
CC init/version.o
LD init/built-in.o
LD vmlinux
fs/built-in.o: In function `do_proc_sys_lookup':
proc_sysctl.c:(.text+0x26583): undefined reference to `sysctl_head_next'
fs/built-in.o: In function `proc_sys_revalidate':
proc_sysctl.c:(.text+0x265bb): undefined reference to `sysctl_head_finish'
fs/built-in.o: In function `proc_sys_readdir':
proc_sysctl.c:(.text+0x26720): undefined reference to `sysctl_head_next'
proc_sysctl.c:(.text+0x267d8): undefined reference to `sysctl_head_finish'
proc_sysctl.c:(.text+0x268e7): undefined reference to `sysctl_head_next'
proc_sysctl.c:(.text+0x26910): undefined reference to `sysctl_head_finish'
fs/built-in.o: In function `proc_sys_write':
proc_sysctl.c:(.text+0x2695d): undefined reference to `sysctl_perm'
proc_sysctl.c:(.text+0x2699c): undefined reference to `sysctl_head_finish'
fs/built-in.o: In function `proc_sys_read':
proc_sysctl.c:(.text+0x269e9): undefined reference to `sysctl_perm'
proc_sysctl.c:(.text+0x26a25): undefined reference to `sysctl_head_finish'
fs/built-in.o: In function `proc_sys_permission':
proc_sysctl.c:(.text+0x26ad1): undefined reference to `sysctl_perm'
proc_sysctl.c:(.text+0x26adb): undefined reference to `sysctl_head_finish'
fs/built-in.o: In function `proc_sys_lookup':
proc_sysctl.c:(.text+0x26b39): undefined reference to `sysctl_head_finish'
make: *** [vmlinux] Virhe 1
All those functions are in fs/proc/proc_sysctl.c, which has no CONFIG_
#define's in it, so the patch makes the compilation of that file to depend
on CONFIG_PROC_SYSCTL (the simplest choice).
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This cancel_delayed_work call is called from a function that is only called
from a piece of code that immediate follows a cancel and destruction of the
workqueue, so it's clearly a mistake.
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The reused clientid here is a more of a problem for the client than the
server, and the client can report the problem itself if it's serious.
Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A regression introduced in the last set of acl patches removed the
INHERIT_ONLY flag from aces derived from the posix acl. Fix.
Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
->readdir passes lofft_t offsets (used as nfs cookies) to
nfs3svc_encode_entry{,_plus}, but when they pass it on to encode_entry it
becomes an 'off_t', which isn't good.
So filesystems that returned 64bit offsets would lose.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ocfs2 wants to implement it's own splice write actor so that it can better
manage cluster / page locks. This lets us re-use the rest of splice write
while only providing our own code where it's actually important.
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Splice does not need to readpage to bring the page uptodate before writing
to it, because prepare_write will take care of that for us.
Splice is also wrong to SetPageUptodate before the page is actually uptodate.
This results in the old uninitialised memory leak. This gets fixed as a
matter of course when removing the readpage logic.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Stealing pages with splice is problematic because we cannot just insert
an uptodate page into the pagecache and hope the filesystem can take care
of it later.
We also cannot just ClearPageUptodate, then hope prepare_write does not
write anything into the page, because I don't think prepare_write gives
that guarantee.
Remove support for SPLICE_F_MOVE for now. If we really want to bring it
back, we might be able to do so with a the new filesystem buffered write
aops APIs I'm working on. If we really don't want to bring it back, then
we should decide that sooner rather than later, and remove the flag and
all the stealing infrastructure before anybody starts using it.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
In dlm_migrate_lockres(), we check upfront whether the lockres is a
candidate for migration. This patch encapsulates that code in a separate
function so that dlm_empty_lockres() can also use it during umount. This
patch addresses the umount process spinning problem.
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
During umount, the umount thread migrates the lockres' and the dlm_thread
frees the empty lockres'. Due to a race, the reference counting on the
lockres goes awry leading to extra puts.
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
This patch makes te needlessly global struct v9fs_cached_file_operations
static.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
A little mistake in 8a2bfdcbfa is making all
transactions synchronous, which reduces ext3 performance to comical levels.
Cc: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix the /proc/pid/stat representation of executable boundaries. It should
show the bounds of the executable, but instead shows the bounds of the
loader.
Before the patch is applied, the bug can be seen by examining, say, inetd:
# ps | grep inetd
610 root 0 S /usr/sbin/inetd -i
# cat /proc/610/maps
c0bb0000-c0bba788 r-xs 00000000 00:0b 14582157 /lib/ld-uClibc-0.9.28.so
c3180000-c31dede4 r-xs 00000000 00:0b 14582179 /lib/libuClibc-0.9.28.so
c328c000-c328ea00 rw-p 00008000 00:0b 14582157 /lib/ld-uClibc-0.9.28.so
c3290000-c329b6c0 rw-p 00000000 00:00 0
c32a0000-c32c0000 rwxp 00000000 00:00 0
c32d4000-c32d8000 rw-p 00000000 00:00 0
c3394000-c3398000 rw-p 00000000 00:00 0
c3458000-c345f464 r-xs 00000000 00:0b 16384612 /usr/sbin/inetd
c3470000-c34748f8 rw-p 00004000 00:0b 16384612 /usr/sbin/inetd
c34cc000-c34d0000 rw-p 00000000 00:00 0
c34d4000-c34d8000 rw-p 00000000 00:00 0
c34d8000-c34dc000 rw-p 00000000 00:00 0
# cat /proc/610/stat
610 (inetd) S 1 610 610 0 -1 256 0 0 0 0 0 8 0 0 19 0 1 0 94392000718
950272 0 4294967295 3233480704 3233523592 3274440352 3274439976
3273467584 0 0 4096 90115 3221712796 0 0 17 0 0 0 0
The code boundaries are 3233480704 to 3233523592, which are:
(gdb) p/x 3233480704
$1 = 0xc0bb0000
(gdb) p/x 3233523592
$2 = 0xc0bba788
Which corresponds to this line in the maps file:
c0bb0000-c0bba788 r-xs 00000000 00:0b 14582157 /lib/ld-uClibc-0.9.28.so
Which is wrong. After the patch is applied, the maps file is pretty much
identical (there's some minor shuffling of the location of some of the
anonymous VMAs), but the stat file is now:
# cat /proc/610/stat
610 (inetd) S 1 610 610 0 -1 256 0 0 0 0 0 7 0 0 18 0 1 0 94392000722
950272 0 4294967295 3276111872 3276141668 3274440352 3274439976
3273467584 0 0 4096 90115 3221712796 0 0 17 0 0 0 0
The code boundaries are then 3276111872 to 3276141668, which are:
(gdb) p/x 3276111872
$1 = 0xc3458000
(gdb) p/x 3276141668
$2 = 0xc345f464
And these correspond to this line in the maps file instead:
c3458000-c345f464 r-xs 00000000 00:0b 16384612 /usr/sbin/inetd
Which is now correct.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6:
[CIFS] Allow reset of file to ATTR_NORMAL when archive bit not set
[CIFS] Do not negotiate new POSIX_PATH_OPERATIONS_CAP yet
[CIFS] reset mode when client notices that ATTR_READONLY is no longer set
Since freezable workqueues are broken in 2.6.21-rc
(cf. http://marc.theaimsgroup.com/?l=linux-kernel&m=116855740612755,
http://marc.theaimsgroup.com/?l=linux-kernel&m=117261312523921&w=2)
it's better to change the only user of them, which is XFS, to use "normal"
nonfreezable workqueues.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: David Chinner <dgc@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When a file had a dos attribute of 0x1 (readonly - but dos attribute
of archive was not set) - doing chmod 0777 or equivalent would
try to set a dos attribute of 0 (which some servers ignore)
rather than ATTR_NORMAL (0x20) which most servers accept.
Does not affect servers which support the CIFS Unix Extensions.
Acked-by: Prasad Potluri <pvp@us.ibm.com>
Acked-by: Shirish Pargaonkar <shirishp@us.ibm.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
This bug was seen on ppc64, but it could have occurred on any
architecture with a page size of 64k or above. The problem is that in
fs/binfmt_elf.c:randomize_stack_top() randomizes the stack to within
0x7ff pages. On 4k page machines, this is 8MB; on 64k page boxes, this
is 128MB.
The problem is that the new binary layout (selected in
arch_pick_mmap_layout) places the mapping segment 128MB or the stack
rlimit away from the top of the process memory, whichever is larger. If
you chose an rlimit of less than 128MB (most defaults are in the 8Mb
range) then you can end up having your entire stack randomized away.
The fix is to make randomize_stack_top() only steal at most 8MB, which this
patch does. However, I have to point out that even with this, your stack
rlimit might not be exactly what you get if it's > 128MB, because you're
still losing the random offset of up to 8MB.
The true fix should be to leave an explicit gap for the randomization plus
a buffer when determining mmap_base, but that would involve fixing all the
architectures.
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove the misleading "Presently only useful on the IA-64 platform" text
from the EFI partition Kconfig.
EFI partitions are also used by Apple on their Intel-based machines and
thus you need EFI partition support if you (for example) want to attach
such a machine in target disk mode.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Matt Domsch <Matt_Domsch@dell.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
