The new (early 2010) implementation of synchronize_sched_expedited() uses
try_stop_cpu() to force a context switch on every CPU. It also permits
concurrent calls to synchronize_sched_expedited() to share a single call
to try_stop_cpu() through use of an atomically incremented
synchronize_sched_expedited_count variable. Unfortunately, this is
subject to failure as follows:
o Task A invokes synchronize_sched_expedited(), try_stop_cpus()
succeeds, but Task A is preempted before getting to the atomic
increment of synchronize_sched_expedited_count.
o Task B also invokes synchronize_sched_expedited(), with exactly
the same outcome as Task A.
o Task C also invokes synchronize_sched_expedited(), again with
exactly the same outcome as Tasks A and B.
o Task D also invokes synchronize_sched_expedited(), but only
gets as far as acquiring the mutex within try_stop_cpus()
before being preempted, interrupted, or otherwise delayed.
o Task E also invokes synchronize_sched_expedited(), but only
gets to the snapshotting of synchronize_sched_expedited_count.
o Tasks A, B, and C all increment synchronize_sched_expedited_count.
o Task E fails to get the mutex, so checks the new value
of synchronize_sched_expedited_count. It finds that the
value has increased, so (wrongly) assumes that its work
has been done, returning despite there having been no
expedited grace period since it began.
The solution is to have the lowest-numbered CPU atomically increment
the synchronize_sched_expedited_count variable within the
synchronize_sched_expedited_cpu_stop() function, which is under
the protection of the mutex acquired by try_stop_cpus(). However, this
also requires that piggybacking tasks wait for three rather than two
instances of try_stop_cpu(), because we cannot control the order in
which the per-CPU callback function occur.
Cc: Tejun Heo <tj@kernel.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Lai's RCU-callback immediate-adoption patch changes the RCU tracing
output, so update tracing.txt. Also update a few comments to clarify
the synchronization design.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
When we handle the CPU_DYING notifier, the whole system is stopped except
for the current CPU. We therefore need no synchronization with the other
CPUs. This allows us to move any orphaned RCU callbacks directly to the
list of any online CPU without needing to run them through the global
orphan lists. These global orphan lists can therefore be dispensed with.
This commit makes thes changes, though currently victimizes CPU 0 @@@.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The first version of synchronize_sched_expedited() used the migration
code in the scheduler, and was therefore implemented in kernel/sched.c.
However, the more recent version of this code no longer uses the
migration code, so this commit moves it to the main RCU source files.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The TREE_RCU tracing had obsolete rcuclassic_trace_init() and
rcuclassic_trace_cleanup() function names. This commit brings them
up to date: rcutree_trace_init() and rcutree_trace_cleanup(),
respectively.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
RCU priority boosting's tracing did not distinguish between ongoing
boosting and completion of boosting. This commit therefore adds this
capability.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Add tracing for the tiny RCU implementations, including statistics on
boosting in the case of TINY_PREEMPT_RCU and RCU_BOOST.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Add priority boosting, but only for TINY_PREEMPT_RCU. This is enabled
by the default-off RCU_BOOST kernel parameter. The priority to which to
boost preempted RCU readers is controlled by the RCU_BOOST_PRIO kernel
parameter (defaulting to real-time priority 1) and the time to wait
before boosting the readers blocking a given grace period is controlled
by the RCU_BOOST_DELAY kernel parameter (defaulting to 500 milliseconds).
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Currently, if CONFIG_CIFS_FSCACHE is set, fscache is enabled on files opened
as read-only irrespective of the 'fsc' mount option. Fix this by enabling
fscache only if 'fsc' mount option is specified explicitly.
Remove an extraneous cFYI debug message and fix a typo while at it.
Reported-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Currently, it is possible to specify 'fsc' mount option even if
CONFIG_CIFS_FSCACHE has not been set. The option is being ignored silently
while the user fscache functionality to work. Fix this by raising error when
the CONFIG option is not set.
Reported-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Add extended attribute name system.cifs_acl
Get/generate cifs/ntfs acl blob and hand over to the invoker however
it wants to parse/process it under experimental configurable option CIFS_ACL.
Do not get CIFS/NTFS ACL for xattr for attribute system.posix_acl_access
Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Change the name of function mode_to_acl to mode_to_cifs_acl.
Handle return code in functions mode_to_cifs_acl and
cifs_acl_to_fattr.
Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Only make swapper_pg_dir readonly and pinned when generic x86 architecture code
(which also starts on initial_page_table) switches to it. This helps ensure
that the generic setup paths work on Xen unmodified. In particular
clone_pgd_range writes directly to the destination pgd entries and is used to
initialise swapper_pg_dir so we need to ensure that it remains writeable until
the last possible moment during bring up.
This is complicated slightly by the need to avoid sharing kernel PMD entries
when running under Xen, therefore the Xen implementation must make a copy of
the kernel PMD (which is otherwise referred to by both intial_page_table and
swapper_pg_dir) before switching to swapper_pg_dir.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
PowerPC relies on IRQ-disable to guard against RCU quiecent states,
use the appropriate RCU call version.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This reverts commit e0fdace10e.
On-list discussion seems to suggest that the robustness fixes for printk
make this unnecessary and DaveM has also agreed in person at Kernel Summit
and on list.
The main problem with this code is once we hit a lockdep splat we always
keep oops_in_progress set, the console layer uses oops_in_progress with KMS
to decide when it should be showing the oops and not showing X, so it causes
problems around suspend/resume time when a userspace resume can cause a console
switch away from X, only if oops_in_progress is set (which is what we want
if an oops actually is in progress, but not because we had a lockdep splat
2 days prior).
Cc: David S Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Like in the "TTY: don't allow reopen when ldisc is changing" patch,
this one fixes a TTY WARNING as described in the option 1) there:
1) __tty_hangup from tty_ldisc_hangup to tty_ldisc_enable. During this
section tty_lock is held. However tty_lock is temporarily dropped in
the middle of the function by tty_ldisc_hangup.
The fix is to introduce a new flag which we set during the unlocked
window and check it in tty_reopen too. The flag is TTY_HUPPING and is
cleared after TTY_HUPPED is set.
While at it, remove duplicate TTY_HUPPED set_bit. The one after
calling ops->hangup seems to be more correct. But anyway, we hold
tty_lock, so there should be no difference.
Also document the function it does that kind of crap.
Nicely reproducible with two forked children:
static void do_work(const char *tty)
{
if (signal(SIGHUP, SIG_IGN) == SIG_ERR) exit(1);
setsid();
while (1) {
int fd = open(tty, O_RDWR|O_NOCTTY);
if (fd < 0) continue;
if (ioctl(fd, TIOCSCTTY)) continue;
if (vhangup()) continue;
close(fd);
}
exit(0);
}
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Reported-by: <Valdis.Kletnieks@vt.edu>
Reported-by: Kyle McMartin <kyle@mcmartin.ca>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
There are many WARNINGs like the following reported nowadays:
WARNING: at drivers/tty/tty_io.c:1331 tty_open+0x2a2/0x49a()
Hardware name: Latitude E6500
Modules linked in:
Pid: 1207, comm: plymouthd Not tainted 2.6.37-rc3-mmotm1123 #3
Call Trace:
[<ffffffff8103b189>] warn_slowpath_common+0x80/0x98
[<ffffffff8103b1b6>] warn_slowpath_null+0x15/0x17
[<ffffffff8128a3ab>] tty_open+0x2a2/0x49a
[<ffffffff810fd53f>] chrdev_open+0x11d/0x146
...
This means tty_reopen is called without TTY_LDISC set. For further
considerations, note tty_lock is held in tty_open. TTY_LDISC is cleared in:
1) __tty_hangup from tty_ldisc_hangup to tty_ldisc_enable. During this
section tty_lock is held. However tty_lock is temporarily dropped in
the middle of the function by tty_ldisc_hangup.
2) tty_release via tty_ldisc_release till the end of tty existence. If
tty->count <= 1, tty_lock is taken, TTY_CLOSING bit set and then
tty_ldisc_release called. tty_reopen checks TTY_CLOSING before checking
TTY_LDISC.
3) tty_set_ldisc from tty_ldisc_halt to tty_ldisc_enable. We:
* take tty_lock, set TTY_LDISC_CHANGING, put tty_lock
* call tty_ldisc_halt (clear TTY_LDISC), tty_lock is _not_ held
* do some other work
* take tty_lock, call tty_ldisc_enable (set TTY_LDISC), put
tty_lock
I cannot see how 2) can be a problem, as there I see no race. OTOH, 1)
and 3) can happen without problems. This patch the case 3) by checking
TTY_LDISC_CHANGING along with TTY_CLOSING in tty_reopen. 1) will be
fixed in the following patch.
Nicely reproducible with two processes:
while (1) {
fd = open("/dev/ttyS1", O_RDWR);
if (fd < 0) {
warn("open");
continue;
}
close(fd);
}
--------
while (1) {
fd = open("/dev/ttyS1", O_RDWR);
ld1 = 0; ld2 = 2;
while (1) {
ioctl(fd, TIOCSETD, &ld1);
ioctl(fd, TIOCSETD, &ld2);
}
close(fd);
}
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Reported-by: <Valdis.Kletnieks@vt.edu>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
We should never return positive values from ldisc->open, tty layer
doesn't (and never did) expect that.
If we do that, weird things like warnings in tty_ldisc_close happen.
Not sure if dev->base_addr is used somehow now.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Andrew Hendry <andrew.hendry@gmail.com>
Cc: linux-x25@vger.kernel.org
Tested-by: Sergey Lapin <slapin@ossfans.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
When a concrete ldisc open fails in tty_ldisc_open, we forget to clear
TTY_LDISC_OPEN. This causes a false warning on the next ldisc open:
WARNING: at drivers/char/tty_ldisc.c:445 tty_ldisc_open+0x26/0x38()
Hardware name: System Product Name
Modules linked in: ...
Pid: 5251, comm: a.out Tainted: G W 2.6.32-5-686 #1
Call Trace:
[<c1030321>] ? warn_slowpath_common+0x5e/0x8a
[<c1030357>] ? warn_slowpath_null+0xa/0xc
[<c119311c>] ? tty_ldisc_open+0x26/0x38
[<c11936c5>] ? tty_set_ldisc+0x218/0x304
...
So clear the bit when failing...
Introduced in c65c9bc3ef (tty: rewrite the ldisc locking) back in
2.6.31-rc1.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Reported-by: Sergey Lapin <slapin@ossfans.org>
Tested-by: Sergey Lapin <slapin@ossfans.org>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* 'omap-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap-2.6:
OMAP2+: PM/serial: hold console semaphore while OMAP UARTs are disabled
OMAP: UART: don't resume UARTs that are not enabled.
Some Lenovos have TPMs that require a quirk to function correctly. This can
be autodetected by checking whether the device has a _HID of INTC0102. This
is an invalid PNPid, and as such is discarded by the pnp layer - however
it's still present in the ACPI code, so we can pull it out that way. This
means that the quirk won't be automatically applied on non-ACPI systems,
but without ACPI we don't have any way to identify the chip anyway so I
don't think that's a great concern.
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Acked-by: Rajiv Andrade <srajiv@linux.vnet.ibm.com>
Tested-by: Jiri Kosina <jkosina@suse.cz>
Tested-by: Andy Isaacson <adi@hexapodia.org>
Signed-off-by: James Morris <jmorris@namei.org>
Xen will shoot all the VCPUs when we do a shutdown hypercall, so there's
no need to do it manually.
In any case it will fail because all the IPI irqs have been pulled
down by this point, so the cross-CPU calls will simply hang forever.
Until change 76fac077db the function calls
were not synchronously waited for, so this wasn't apparent. However after
that change the calls became synchronous leading to a hang on shutdown
on multi-VCPU guests.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stable Kernel <stable@kernel.org>
Cc: Alok Kataria <akataria@vmware.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable: (24 commits)
Btrfs: don't use migrate page without CONFIG_MIGRATION
Btrfs: deal with DIO bios that span more than one ordered extent
Btrfs: setup blank root and fs_info for mount time
Btrfs: fix fiemap
Btrfs - fix race between btrfs_get_sb() and umount
Btrfs: update inode ctime when using links
Btrfs: make sure new inode size is ok in fallocate
Btrfs: fix typo in fallocate to make it honor actual size
Btrfs: avoid NULL pointer deref in try_release_extent_buffer
Btrfs: make btrfs_add_nondir take parent inode as an argument
Btrfs: hold i_mutex when calling btrfs_log_dentry_safe
Btrfs: use dget_parent where we can UPDATED
Btrfs: fix more ESTALE problems with NFS
Btrfs: handle NFS lookups properly
btrfs: make 1-bit signed fileds unsigned
btrfs: Show device attr correctly for symlinks
btrfs: Set file size correctly in file clone
btrfs: Check if dest_offset is block-size aligned before cloning file
Btrfs: handle the space_cache option properly
btrfs: Fix early enospc because 'unused' calculated with wrong sign.
...
commit: "carl9170: revamp carl9170_tx_prepare"
introduced a peculiar bug that would only show
up if the the module parameter noht is set to 1.
Then all outbound voice, video and background
frames would each invoke a (bogus) RTS/CTS
handshake.
Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
In order for frame injection to work properly for some use cases
(e.g., finding the station entry and keys for encryption), mac80211
needs to find the correct sdata entry. This works when the main vif
is in AP mode, but commit a2c1e3dad5
broke this particular use case for station main vif. While this type of
injection is quite unusual operation, it has some uses and we should fix
it. Do this by changing the monitor vif sdata selection to allow station
vif to be selected instead of limiting it to just AP vifs. We still need
to skip some iftypes to avoid selecting unsuitable vif for injection.
Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
while removing beaconing mode interface, SWBA interrupt
was never disabled when there are no other beaconing interfaces.
Cc: stable@kernel.org
Signed-off-by: Rajkumar Manoharan <rmanoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
With some upcoming changes we'd like to use
the interface types for P2P capability tests.
Enable them now so that when we add those
tests in wpa_supplicant, nothing will break.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The ath9k driver uses a shared pm_qos_request_list structure for all
devices. This causes the following warning if more than one device is
present in the system:
WARNING: at kernel/pm_qos_params.c:234 ath9k_init_device+0x5e8/0x6b0()
pm_qos_add_request() called for already added request
Modules linked in:
Call Trace:
[<802b1cdc>] dump_stack+0x8/0x34
[<8007dd90>] warn_slowpath_common+0x78/0xa4
[<8007de44>] warn_slowpath_fmt+0x2c/0x38
[<801b0828>] ath9k_init_device+0x5e8/0x6b0
[<801bc508>] ath_pci_probe+0x2dc/0x39c
[<80176254>] pci_device_probe+0x64/0xa4
[<8019471c>] driver_probe_device+0xbc/0x188
[<80194854>] __driver_attach+0x6c/0xa4
[<80193e20>] bus_for_each_dev+0x60/0xb0
[<80193580>] bus_add_driver+0xcc/0x268
[<80194c08>] driver_register+0xe0/0x198
[<801764e0>] __pci_register_driver+0x50/0xe0
[<80365f48>] ath9k_init+0x3c/0x6c
[<8006050c>] do_one_initcall+0xfc/0x1d8
[<80355340>] kernel_init+0xd4/0x174
[<800639a4>] kernel_thread_helper+0x10/0x18
---[ end trace 5345fc6f870564a6 ]---
This patch fixes that warning by using a separate pm_qos_request_list
sructure for each device.
Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
card->priv must not be accessed after lbs_remove_card() was called
as lbs_remove_card() frees card->priv via free_netdev().
For libertas_sdio this is a regression introduced by 23b149c189.
The correct fix to the issue described there is simply to remove the
assignment. This flag is set at the appropriate time inside
lbs_remove_card anyway.
Reported-by: Daniel Drake <dsd@laptop.org>
Signed-off-by: Sven Neumann <s.neumann@raumfeld.com>
Signed-off-by: Daniel Drake <dsd@laptop.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
"priv" is stored at the end of the wiphy structure, which is freed
during the call to lbs_cfg_free(). It must not be touched afterwards.
Remove the unnecessary NULL assignment causing this memory corruption.
Signed-off-by: Daniel Drake <dsd@laptop.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
eth_type_trans tries to pull data with the length of the ethernet header
from the skb. We only ensured that enough data for the first ethernet
header and the batman header is available in non-paged memory of the skb
and not for the ethernet after the batman header.
eth_type_trans would fail sometimes with drivers which don't ensure that
all there data is perfectly linearised.
The failure was noticed through a kernel bug Oops generated by the
skb_pull inside eth_type_trans.
Reported-by: Rafal Lesniak <lesniak@eresi-project.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Sven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
We call a lot of the netdevice code when holding if_list_lock which will
spin the whole time. This is not necessary because we only want to
protect the access to the list to be serialized. An extra queue can be
used which hold all interfaces which should be removed and then use that
queue without any locks for netdevice cleanup.
We create a "scheduling while atomic" Oops when calling different
netdevice related functions inside a spinlock protected area on a
preemtible kernel.
Reported-by: Rafal Lesniak <lesniak@eresi-project.org>
Signed-off-by: Sven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Open-source development team extended so contacts updated.
Reviewed-by: Brett Rudley <brudley@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch fixes below error:
CC sound/soc/nuc900/nuc900-pcm.o
sound/soc/nuc900/nuc900-pcm.c: In function 'nuc900_dma_open':
sound/soc/nuc900/nuc900-pcm.c:267: error: 'nuc900_ac97_data' undeclared (first use in this function)
sound/soc/nuc900/nuc900-pcm.c:267: error: (Each undeclared identifier is reported only once
sound/soc/nuc900/nuc900-pcm.c:267: error: for each function it appears in.)
sound/soc/nuc900/nuc900-pcm.c: At top level:
sound/soc/nuc900/nuc900-pcm.c:337: error: expected ',' or ';' before 'static'
sound/soc/nuc900/nuc900-pcm.c:354: error: 'nuc900_soc_platform_probe' undeclared here (not in a function)
make[3]: *** [sound/soc/nuc900/nuc900-pcm.o] Error 1
make[2]: *** [sound/soc/nuc900] Error 2
make[1]: *** [sound/soc] Error 2
make: *** [sound] Error 2
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
