This patch adds stalled-CPU detection to Classic RCU. This capability
is enabled by a new config variable CONFIG_RCU_CPU_STALL_DETECTOR, which
defaults disabled.
This is a debugging feature to detect infinite loops in kernel code, not
something that non-kernel-hackers would be expected to care about.
This feature can detect looping CPUs in !PREEMPT builds and looping CPUs
with preemption disabled in PREEMPT builds. This is essentially a port of
this functionality from the treercu patch, replacing the stall debug patch
that is already in tip/core/rcu (commit 67182ae1c4).
The changes from the patch in tip/core/rcu include making the config
variable name match that in treercu, changing from seconds to jiffies to
avoid spurious warnings, and printing a boot message when this feature
is enabled.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Add rcu_read_lock_sched() and rcu_read_unlock_sched() to rcupdate.h to match the
recently added write-side call_rcu_sched() and rcu_barrier_sched(). They also
match the no-so-recently-added synchronize_sched().
It will help following matching use of the update/read lock primitives. Those
new read lock will replace preempt_disable()/enable() used in pair with
RCU-classic synchronization.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
There's a race between mm->owner assignment and swapoff, more easily
seen when task slab poisoning is turned on. The condition occurs when
try_to_unuse() runs in parallel with an exiting task. A similar race
can occur with callers of get_task_mm(), such as /proc/<pid>/<mmstats>
or ptrace or page migration.
CPU0 CPU1
try_to_unuse
looks at mm = task0->mm
increments mm->mm_users
task 0 exits
mm->owner needs to be updated, but no
new owner is found (mm_users > 1, but
no other task has task->mm = task0->mm)
mm_update_next_owner() leaves
mmput(mm) decrements mm->mm_users
task0 freed
dereferencing mm->owner fails
The fix is to notify the subsystem via mm_owner_changed callback(),
if no new owner is found, by specifying the new task as NULL.
Jiri Slaby:
mm->owner was set to NULL prior to calling cgroup_mm_owner_callbacks(), but
must be set after that, so as not to pass NULL as old owner causing oops.
Daisuke Nishimura:
mm_update_next_owner() may set mm->owner to NULL, but mem_cgroup_from_task()
and its callers need to take account of this situation to avoid oops.
Hugh Dickins:
Lockdep warning and hang below exec_mmap() when testing these patches.
exit_mm() up_reads mmap_sem before calling mm_update_next_owner(),
so exec_mmap() now needs to do the same. And with that repositioning,
there's now no point in mm_need_new_owner() allowing for NULL mm.
Reported-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Paul Menage <menage@google.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/bart/ide-2.6:
cdrom: update ioctl documentation
ide: note that IDE generic may prevent other drivers from attaching
ide-tape: fix vendor strings
Swarm: Fix crash due to missing initialization
* 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus:
[SSB] Initialise dma_mask for SSB_BUSTYPE_SSB devices
[MIPS] BCM47xx: Fix build error due to missing PCI functions
[MIPS] IP27: Switch to dynamic interrupt routing avoding panic on error.
[MIPS] au1000: Make sure GPIO value is zero or one
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb:
kgdboc,tty: Fix tty polling search to use name correctly
kgdb, x86_64: fix PS CS SS registers in gdb serial
kgdb, x86_64: gdb serial has BX and DX reversed
kgdb, x86, arm, mips, powerpc: ignore user space single stepping
kgdb: could not write to the last of valid memory with kgdb
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6:
ALSA: ASoC: Fix another cs4270 error path
ALSA: make the CS4270 driver a new-style I2C driver
* git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-rc-fixes-2.6:
[SCSI] qlogicpti: fix sg list traversal error in continuation entries
[SCSI] Fix hang with split requests
[SCSI] qla2xxx: Defer enablement of RISC interrupts until ISP initialization completes.
Commit f072181e64 ("kconfig: drop the
""trying to assign nonexistent symbol" warning") simply dropped the
warnings, but it does a little more than that, it also marks the current
.config as needed saving, so add this back.
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Recent changes to oldconfig have mixed up the silentoldconfig handling,
so this fixes that by clearly separating that special mode, e.g.
KCONFIG_NOSILENTUPDATE is only relevant here, the .config is written as
needed.
This will also properly close Bug 11230.
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The VFS interface for the 'd_compare()' is a bit special (read: 'odd'),
because it really just essentially replaces a memcmp(). The filesystem
is supposed to just compare the two names with whatever case-independent
or other function.
And when I say 'is supposed to', I obviously mean that 'procfs does odd
things, and actually looks at the dentry that we don't even pass down,
rather than just the name'. Which results in problems, because we
actually call d_compare before we have even verified that the dentry is
still hashed at all.
And that causes a problm since the inode that procfs looks at may have
been free'd and the d_inode pointer is NULL. procfs just assumes that
all dentries are positive, since procfs itself never generates a
negative one. But memory pressure will still result in the dentry
getting torn down, and as it is removed by RCU, it still remains visible
on some lists - and to d_compare.
If the filesystem just did a name comparison, we wouldn't care. And we
could just fix procfs to know about negative dentries too. But rather
than have the low-level filesystems know about internal VFS details,
just move the check for a unhashed dentry up a bit, so that we will only
call d_compare on dentries that are still active.
The actual oops this caused didn't look like a NULL pointer dereference
because procfs did a 'container_of(inode, struct proc_inode, vfs_inode)'
to get at its internal proc_inode information from the inode pointer,
and accessed a field below the inode. So the oops would look something
like
BUG: unable to handle kernel paging request at fffffffffffffff0
IP: [<ffffffff802bc6c6>] proc_sys_compare+0x36/0x50
and was seen on both x86-64 (Alexey Dobriyan and Hugh Dickins) and
ppc64 (Hugh Dickins).
Reported-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Hugh Dickins <hugh@veritas.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-of-by: Linus Torvalds <torvalds@linux-foundation.org>
Conversion to new-style i2c driver missed the error path of the
probe function. Fix it.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Timur Tabi <timur@freescale.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Update the CS4270 ALSA device driver to use the new-style I2C interface.
Starting with the 2.6.27 PowerPC kernel, I2C devices that have entries in the
device trees can no longer be probed by old-style I2C drivers. The device
tree for Freescale MPC8610 HPCD has included an entry for the CS4270 since
2.6.25, but that entry was previously ignored by the PowerPC I2C subsystem.
Since that's no longer the case, the best solution is to update the CS4270
driver to a new-style interface, rather than try to revert the behavior of
new PowerPC I2C subsystem.
Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Boaz writes:
"I've reviewed all patches since Matthew's, and I find one small
problem.
In the load_cmd() there is a compound loop where the first 4 sg's are
set then the rest are set into a memory structure in group of 7 sg's.
Well the second 7-group and on is a bug because sg pointer does not advance.
This is a fall out from Jens's patch."
The reporter, Meelis Roos <mroos@ut.ee>, verified that this patch
does indeed fix his problem with qlogicpti.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Commit 2fd673ecf0 which tried to remove
hardreset for generic accidentally removed it for all flavors as all
others were inheriting from nv_generic_ops. This patch reinstates
nv_hardreset() and puts it into nv_common_ops which all flavors
inherit from. nv_generic_ops now inherits from nv_common_ops and
overrides .hardreset to ATA_OP_NULL.
While at it, explain why nv_hardreset and ATA_OP_NULL override are
necessary.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
The current sg list traversal logic for the continuation entries
doesn't advance the list pointer once all seven slots are used, so the
next continuation entry (if there is one) wrongly begins again at the
start of the sg list.
Fix by advancing the sg pointer after the for_each_sg().
Reported-by: Meelis Roos <mroos@ut.ee>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Correct copy-paste problem: CDROMCLOSETRAY is about closing the tray,
not opening it.
Signed-off-by: Márton Németh <nm127@freemail.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Enabling IDE generic may prevent ATA controllers located on legacy
ports from being attached to more proper driver or can prevent other
controllers which share the IRQ from working. Note it in the help
message.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: xerces8 <xerces8@butn.net>
Cc: Jeff Garzik <jgarzik@pobox.com>
Cc: stein@hermes.si
[bart: s/will grab/may grab/ since Borislav has fixed PCI-case for .28]
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Remove superfluous two bytes from each string buffer and add proper length
format specifiers.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Tested-by: Mark de Wever <koraq@xs4all.nl>
Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
If things are just right this will result in the hws[0]->parent being
passed to ide_host_add() being non-zero and an ooops a little later.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
For SSB_BUSTYPE_SSB type devices, we need to initialize dma_mask using
coherent_dma_mask so that calls to dma_set_mask() succeed.
It fixes the regression on the b44 driver introduced by commit
f225763a7d
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This patch defines pcibios_map_irq() and pcibios_plat_dev_init() for
the BCM47xx platform.
It fixes the regression introduced by commit
aab547ce0d.
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
pcibios_map_irq is no way of returning an error but on IP27 an interrupt
is possibly not routable when running out of resources. So do the
interrupt routing at pcibios_enable_device time.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
David Brownell <david-b@pacbell.net> wrote:
> The problem is that "value" is zero-or-nonzero.
> This code wrongly assumes it's zero-or-one.
> Possible fix: "((!!value) << gpio)".
Signed-off-by: Bruno Randolf <br1@einfach.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
As far as I know no M32R hardware actually has ISA slots.
And ISA drivers don't compile on M32R.
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Hirokazu Takata <takata@linux-m32r.org>
Remove the unused NOHIGHMEM option.
Reviewed-by: Robert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Hirokazu Takata <takata@linux-m32r.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6:
ALSA: remove unneeded power_mutex lock in snd_pcm_drop
ALSA: fix locking in snd_pcm_open*() and snd_rawmidi_open*()
Delete ARM's own cnt32_to_63.h as the copy in include/linux/ should now be
used instead.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The tty_find_polling_driver() routine did not correctly check the base
part of the tty name. This can lead to kgdboc selecting an incorrect
driver, as well as accepting a completely invalid tty such as "echo
ffff0 > /sys/module/kgdboc/parameters/kgdboc".
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
On x86_64 the gdb serial register structure defines the PS (also known
as eflags), CS and SS registers as 4 bytes entities.
This patch splits the x86_64 regnames enum into a 32 and 64 version to
account for the 32 bit entities in the gdb serial packets.
Also the program counter is properly filled in for the sleeping
threads.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
The BX and DX registers in the gdb serial register packet need to be
flipped for gdb to receive the correct data.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
On the x86 arch, user space single step exceptions should be ignored
if they occur in the kernel space, such as ptrace stepping through a
system call.
First check if it is kgdb that is executing a single step, then ensure
it is not an accidental traversal into the user space, while in kgdb,
any other time the TIF_SINGLESTEP is set, kgdb should ignore the
exception.
On x86, arm, mips and powerpc, the kgdb_contthread usage was
inconsistent with the way single stepping is implemented in the kgdb
core. The arch specific stub should always set the
kgdb_cpu_doing_single_step correctly if it is single stepping. This
allows kgdb to correctly process an instruction steps if ptrace
happens to be requesting an instruction step over a system call.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
On the ARM architecture, kgdb will crash the kernel if the last byte
of valid memory is written due to a flush_icache_range flushing
beyond the memory boundary.
Signed-off-by: Atsuo Igarashi <atsuo_igarashi@tripeaks.co.jp>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
* 'linux-next' of git://git.infradead.org/~dedekind/ubifs-2.6:
UBIFS: fix printk format warnings
UBIFS: remove incorrect assert
UBIFS: TNC / GC race fixes
UBIFS: create the name of the background thread in every case
Yet another bug was found in xfs_iext_irec_compact_full() and while the
source of the bug was found it wasn't an easy task to track it down
because the conditions are very difficult to reproduce.
A HUGE thank-you goes to Russell Cattelan and Eric Sandeen for their
significant effort in tracking down the source of this corruption.
xfs_iext_irec_compact_full() and xfs_iext_irec_compact_pages() are almost
identical - they both compact indirect extent lists by moving extents from
subsequent buffers into earlier ones. xfs_iext_irec_compact_pages() only
moves extents if all of the extents in the next buffer will fit into the
empty space in the buffer before it. xfs_iext_irec_compact_full() will go
a step further and move part of the next buffer if all the extents wont
fit. It will then shift the remaining extents in the next buffer up to the
start of the buffer. The bug here was that we did not update er_extoff and
this caused extent list corruption.
It does not appear that this extra functionality gains us much. Calling
xfs_iext_irec_compact_pages() instead will do a good enough job at
compacting the indirect list and will be quicker too.
For the case in xfs_iext_indirect_to_direct() the total number of extents
in the indirect list will fit into one buffer so we will never need the
extra functionality of xfs_iext_irec_compact_full() there.
Also xfs_iext_irec_compact_pages() doesn't need to do a memmove() (the
buffers will never overlap) so we don't want the performance hit that can
incur.
SGI-PV: 987159
SGI-Modid: xfs-linux-melb:xfs-kern:32166a
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
If we don't move all the records from the next buffer into the current
buffer then we need to update the er_extoff field of the next buffer as we
shift the remaining records to the start of the buffer.
SGI-PV: 987159
SGI-Modid: xfs-linux-melb:xfs-kern:32165a
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
Signed-off-by: Russell Cattelan <cattelan@thebarn.com>
Commit ee1e2c82 ("IPoIB: Refresh paths instead of flushing them on SM
change events") changed how paths are flushed on an SM event. This
change introduces a problem if the path record query triggered by
fails, causing path->ah to become NULL. A later successful path query
will then trigger WARN_ON() in path_rec_completion(), and crash
because path->ah has already been freed, so the ipoib_put_ah() inside
the lock in path_rec_completion() may actually drop the last reference
(contrary to the comment that claims this is safe).
Fix this by updating path->ah and freeing old_ah only when the path
record query is successful. This prevents the neighbour AH and that
path AH from getting out of sync.
This fixes <https://bugs.openfabrics.org/show_bug.cgi?id=1194>
Reported-by: Rabah Salem <ravah@mellanox.com>
Debugged-by: Eli Cohen <eli@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The power_mutex lock in snd_pcm_drop may cause a possible deadlock
chain, and above all, it's unneeded. Let's get rid of it.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
The PCM and rawmidi open callbacks have a lock against card->controls_list
but it takes a wrong one, card->controls_rwsem, instead of a right one
card->ctl_files_rwlock. This patch fixes them.
This change also fixes automatically the potential deadlocks due to
mm->mmap_sem in munmap and copy_from/to_user, reported by Sitsofe
Wheeler:
A: snd_ctl_elem_user_tlv(): card->controls_rwsem => mm->mmap_sem
B: snd_pcm_open(): card->open_mutex => card->controls_rwsem
C: munmap: mm->mmap_sem => snd_pcm_release(): card->open_mutex
The patch breaks the chain.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
