configfs_mkdir() creates a new item by calling its parent's
->make_item/group() functions. Once that object is created,
configfs_mkdir() calls try_module_get() on the new item's module. If it
succeeds, the module owning the new item cannot be unloaded, and
configfs is safe to reference the item.
If the item and the subsystem it belongs to are part of the same module,
the subsystem is also pinned. This is the common case.
However, if the subsystem is made up of multiple modules, this may not
pin the subsystem. Thus, it would be possible to unload the toplevel
subsystem module while there is still a child item. Thus, we now
try_module_get() the subsystem's module. This only really affects
children of the toplevel subsystem group. Deeper children already have
their parents pinned.
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
When checking for user-created elements under an item to be removed by rmdir(),
configfs_detach_prep() counts fake configfs_dirents created by dir_open() as
user-created and fails when finding one. It is however perfectly valid to remove
a directory that is open.
Simply make configfs_detach_prep() skip fake configfs_dirent, like it already
does for attributes, and like detach_groups() does.
Signed-off-by: Louis Rilling <louis.rilling@kerlabs.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
Once a new configfs directory is created by configfs_attach_item() or
configfs_attach_group(), a failure in the remaining initialization steps leads
to removing a directory which inode the VFS may have already accessed.
This commit adds the necessary inode locking to safely remove configfs
directories while cleaning up after a failure. As an advantage, the locking
rules of populate_groups() and detach_groups() become the same: the caller must
have the group's inode mutex locked.
Signed-off-by: Louis Rilling <louis.rilling@kerlabs.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
process 1: process 2:
configfs_mkdir("A")
attach_group("A")
attach_item("A")
d_instantiate("A")
populate_groups("A")
mutex_lock("A")
attach_group("A/B")
attach_item("A")
d_instantiate("A/B")
mkdir("A/B/C")
do_path_lookup("A/B/C", LOOKUP_PARENT)
ok
lookup_create("A/B/C")
mutex_lock("A/B")
ok
configfs_mkdir("A/B/C")
ok
attach_group("A/C")
attach_item("A/C")
d_instantiate("A/C")
populate_groups("A/C")
mutex_lock("A/C")
attach_group("A/C/D")
attach_item("A/C/D")
failure
mutex_unlock("A/C")
detach_groups("A/C")
nothing to do
mkdir("A/C/E")
do_path_lookup("A/C/E", LOOKUP_PARENT)
ok
lookup_create("A/C/E")
mutex_lock("A/C")
ok
configfs_mkdir("A/C/E")
ok
detach_item("A/C")
d_delete("A/C")
mutex_unlock("A")
detach_groups("A")
mutex_lock("A/B")
detach_group("A/B")
detach_groups("A/B")
nothing since no _default_ group
detach_item("A/B")
mutex_unlock("A/B")
d_delete("A/B")
detach_item("A")
d_delete("A")
Two bugs:
1/ "A/B/C" and "A/C/E" are created, but never removed while their parent are
removed in the end. The same could happen with symlink() instead of mkdir().
2/ "A" and "A/C" inodes are not locked while detach_item() is called on them,
which may probably confuse VFS.
This commit fixes 1/, tagging new directories with CONFIGFS_USET_CREATING before
building the inode and instantiating the dentry, and validating the whole
group+default groups hierarchy in a second pass by clearing
CONFIGFS_USET_CREATING.
mkdir(), symlink(), lookup(), and dir_open() simply return -ENOENT if
called in (or linking to) a directory tagged with CONFIGFS_USET_CREATING. This
does not prevent userspace from calling stat() successfuly on such directories,
but this prevents userspace from adding (children to | symlinking from/to |
read/write attributes of | listing the contents of) not validated items. In
other words, userspace will not interact with the subsystem on a new item until
the new item creation completes correctly.
It was first proposed to re-use CONFIGFS_USET_IN_MKDIR instead of a new
flag CONFIGFS_USET_CREATING, but this generated conflicts when checking the
target of a new symlink: a valid target directory in the middle of attaching
a new user-created child item could be wrongly detected as being attached.
2/ is fixed by next commit.
Signed-off-by: Louis Rilling <louis.rilling@kerlabs.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
On a similar pattern as mkdir() vs rmdir(), a failing symlink() may make rmdir()
fail for the symlink's parent and the symlink's target as well.
failing symlink() making target's rmdir() fail:
process 1: process 2:
symlink("A/S" -> "B")
allow_link()
create_link()
attach to "B" links list
rmdir("B")
detach_prep("B")
error because of new link
configfs_create_link("A", "S")
error (eg -ENOMEM)
failing symlink() making parent's rmdir() fail:
process 1: process 2:
symlink("A/D/S" -> "B")
allow_link()
create_link()
attach to "B" links list
configfs_create_link("A/D", "S")
make_dirent("A/D", "S")
rmdir("A")
detach_prep("A")
detach_prep("A/D")
error because of "S"
create("S")
error (eg -ENOMEM)
We cannot use the same solution as for mkdir() vs rmdir(), since rmdir() on the
target cannot wait on the i_mutex of the new symlink's parent without risking a
deadlock (with other symlink() or sys_rename()). Instead we define a global
mutex protecting all configfs symlinks attachment, so that rmdir() can avoid the
races above.
Signed-off-by: Louis Rilling <louis.rilling@kerlabs.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
The rule for configfs symlinks is that symlinks always point to valid
config_items, and prevent the target from being removed. However,
configfs_symlink() only checks that it can grab a reference on the target item,
without ensuring that it remains alive until the symlink is correctly attached.
This patch makes configfs_symlink() fail whenever the target is being removed,
using the CONFIGFS_USET_DROPPING flag set by configfs_detach_prep() and
protected by configfs_dirent_lock.
This patch introduces a similar (weird?) behavior as with mkdir failures making
rmdir fail: if symlink() races with rmdir() of the parent directory (or its
youngest user-created ancestor if parent is a default group) or rmdir() of the
target directory, and then fails in configfs_create(), this can make the racing
rmdir() fail despite the concerned directory having no user-created entry (resp.
no symlink pointing to it or one of its default groups) in the end.
This behavior is fixed in later patches.
Signed-off-by: Louis Rilling <louis.rilling@kerlabs.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
We now use PTR_ERR() in the ->make_item() and ->make_group() operations.
Folks including configfs.h need err.h.
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
The fdiv detection code writes s32 integer into
the boot_cpu_data.fdiv_bug.
However, the boot_cpu_data.fdiv_bug is only char (s8)
field so the detection overwrites already set fields for
other bugs, e.g. the f00f bug field.
Use local s32 variable to receive result.
This is a partial fix to Bugzilla #9928 - fixes wrong
information about the f00f bug (tested) and probably
for coma bug (I have no cpu to test this).
Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
It would have saved both a bug submitter and me a few hours if
scripts/ver_linux had picked the same gcc as the build.
Since I can't see any reason why it fiddles with PATH at all this patch
therefore removes the PATH setting.
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Change the "If unsure" message to match the default value.
Signed-off-by: John Kacur <jkacur at gmail dot com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Most of this function takes place inside of an unnecessary "else"
clause. The other 2 cases both return 0, so we can remove some
indentation here.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Allocate and free everyting outside of the locked section.
Spotted-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
Fixed-by: Seguier Regis <rseguier@e-teleport.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
It should help people fix the bugs in my code :o)
Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The extern flag currently is not included in type dump files
(genksyms --dump-types). Include that flag there for completeness.
Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
We are having two kinds of problems with genksyms today: fake checksum
changes without actual ABI changes, and changes which we would rather like
to ignore (such as an additional field at the end of a structure that
modules are not supposed to touch, for example).
I have thought about ways to improve genksyms and compute checksums
differently to avoid those problems, but in the end I don't see a
fundamentally better way. So here are some genksyms patches for at least
making the checksums more easily manageable, if we cannot fully fix them.
In addition to the bugfixes (the first two patches), this allows genksyms
to track checksum changes and report why a checksum changed (third patch),
and to selectively ignore changes (fourth patch).
This patch:
Gcc __attribute__ definitions may occur repeatedly, e.g.,
static int foo __attribute__((__used__))
__attribute__((aligned (16)));
The genksyms parser does not understand this, and generates a syntax error.
Fix this case.
Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
fix:
On Thursday 31 July 2008, Ingo Molnar wrote:
> drivers/built-in.o: In function `hpet_alloc':
> : undefined reference to `__udivdi3'
> drivers/built-in.o: In function `hpet_alloc':
> : undefined reference to `__umoddi3'
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Minor /dev/hpet updates and bugfixes:
* Remove dead code, mostly remnants of an incomplete/unusable
kernel interface ... noted when addressing "sparse" warnings:
+ hpet_unregister() and a routine it calls
+ hpet_task and all references, including hpet_task_lock
+ hpet_data.hd_flags (and HPET_DATA_PLATFORM)
* Correct and improve boot message:
+ displays *counter* (shared between comparators) bit width,
not *timer* bit widths (which are often mixed)
+ relabel "timers" as "comparators"; this is less confusing,
they are not independent like normal timers are (sigh)
+ display MHz not Hz; it's never less than 10 MHz.
* Tighten and correct the userspace interface code
+ don't accidentally program comparators in 64-bit mode using
32-bit values ... always force comparators into 32-bit mode
+ provide the correct bit definition flagging comparators with
periodic capability ... the ABI is unchanged
* Update Documentation/hpet.txt
+ be more correct and current
+ expand description a bit
+ don't mention that now-gone kernel interface
Plus, add a FIXME comment for something that could cause big trouble
on systems with more capable HPETs than at least Intel seems to ship.
It seems that few folk use this userspace interface; it's not very
usable given the general lack of HPET IRQ routing. I'm told that
the only real point of it any more is to mmap for fast timestamps;
IMO that's handled better through the gettimeofday() vsyscall.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When we traverse the graph, either forwards or backwards, we
are interested in whether a certain property exists somewhere
in a node reachable in the graph.
Therefore it is never necessary to traverse through a node more
than once to get a correct answer to the given query.
Take advantage of this property using a global ID counter so that we
need not clear all the markers in all the lock_class entries before
doing a traversal. A new ID is choosen when we start to traverse, and
we continue through a lock_class only if it's ID hasn't been marked
with the new value yet.
This short-circuiting is essential especially for high CPU count
systems. The scheduler has a runqueue per cpu, and needs to take
two runqueue locks at a time, which leads to long chains of
backwards and forwards subgraphs from these runqueue lock nodes.
Without the short-circuit implemented here, a graph traversal on
a runqueue lock can take up to (1 << (N - 1)) checks on a system
with N cpus.
For anything more than 16 cpus or so, lockdep will eventually bring
the machine to a complete standstill.
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Fix all errors and many warnings reported by checkpatch.pl
without change sys_x86_64.o
arch/x86/kernel/sys_x86_64.o:
text data bss dec hex filename
1567 0 0 1567 61f sys_x86_64.o.after
1567 0 0 1567 61f sys_x86_64.o.before
md5:
de28ffedcb5851dfd7ec87a03afec1fd sys_x86_64.o.after
de28ffedcb5851dfd7ec87a03afec1fd sys_x86_64.o.before
Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Fix all errors and many warnings reported by checkpath.pl.
Except the change of include <asm/io.h> to <linux/io.h>
the traps.o before and after changes are the same.
Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Fix all errors and many warnings reported by checkpatch.pl
without change signal_64.o
arch/x86/kernel/signal_64.o
text data bss dec hex filename
5143 0 8 5151 141f signal_64.o.after
5143 0 8 5151 141f signal_64.o.before
md5:
e68718092b3641cb27e79e55ce57e3ad signal_64.o.after
e68718092b3641cb27e79e55ce57e3ad signal_64.o.before
Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When taking the time of a remote CPU, use the opportunity to
couple (sync) the clocks to each other. (in a monotonic way)
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Mike Galbraith <efault@gmx.de>
- return the current clock instead of letting callers
fetch it from scd->clock
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Mike Galbraith <efault@gmx.de>
eliminate prev_raw and use tick_raw instead.
It's enough to base the current time on the scheduler tick timestamp
alone - the monotonicity and maximum checks will prevent any damage.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Mike Galbraith <efault@gmx.de>
Found an interactivity problem on a quad core test-system - simple
CPU loops would occasionally delay the system un an unacceptable way.
After much debugging with Peter Zijlstra it turned out that the problem
is caused by the string of sched_clock() changes - they caused the CPU
clock to jump backwards a bit - which confuses the scheduler arithmetics.
(which is unsigned for performance reasons)
So revert:
# c300ba2: sched_clock: and multiplier for TSC to gtod drift
# c0c8773: sched_clock: only update deltas with local reads.
# af52a90: sched_clock: stop maximum check on NO HZ
# f7cce27: sched_clock: widen the max and min time
This solves the interactivity problems.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Mike Galbraith <efault@gmx.de>
Currently paravirt_ops alloc_p*() uses u32 for the pfn args. We should
change that later, but while the pfn parameter is still u32, we need to
cast the PFN_PHYS() argument at xen_alloc_ptpage() to unsigned long,
otherwise it will lose bits on the shift.
I think PFN_PHYS() should behave better when fed with smaller integers,
but a cast to unsigned long won't be enough for all cases on 32-bit PAE,
and a cast to u64 would be overkill for most users of PFN_PHYS().
We could have two different flavors of PFN_PHYS: one for low pages
only (unsigned long) and another that works for any page (u64)),
but while we don't have it, we will need the cast to unsigned long on
xen_alloc_ptpage().
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Add a proper comment for set_aliased_prot() and fix an
unsigned long/void * warning.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
For some reason I managed to miss a bunch of irq-related functions
which also need to be compiled without -pg when using ftrace. This
patch moves them into their own file, and starts a cleanup process
I've been meaning to do anyway.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: "Alex Nixon (Intern)" <Alex.Nixon@eu.citrix.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The z10 system supports large pages, kvm-s390 doesnt.
Make sure that we dont advertise large pages to avoid the guest crashing as
soon as the guest kernel activates DAT.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
All the call sites are #if 0'd out and we have a much more
useful global cpu dumping facility these days. smp_report_regs()
is way too verbose to be usable.
Signed-off-by: David S. Miller <davem@davemloft.net>
It just clutters everything up and even though I wrote that hack I
can't remember having used it in the last 5 years or so.
Signed-off-by: David S. Miller <davem@davemloft.net>
Deleting a timer with del_timer doesn't guarantee, that the
timer function is not running at the moment of deletion. Thus
in the xt_hashlimit case we can get into a ticklish situation
when the htable_gc rearms the timer back and we'll actually
delete an entry with a pending timer.
Fix it with using del_timer_sync().
AFAIK del_timer_sync checks for the timer to be pending by
itself, so I remove the check.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
The thing is that recent_mt_destroy first flushes the entries
from table with the recent_table_flush and only *after* this
removes the proc file, corresponding to that table.
Thus, if we manage to write to this file the '+XXX' command we
will leak some entries. If we manage to write there a 'clean'
command we'll race in two recent_table_flush flows, since the
recent_mt_destroy calls this outside the recent_lock.
The proper solution as I see it is to remove the proc file first
and then go on with flushing the table. This flushing becomes
safe w/o the lock, since the table is already inaccessible from
the outside.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
In order to time out dead connections quicker, keep track of outstanding data
and cap the timeout.
Suggested by Herbert Xu.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
