Impact: do not confuse user on small trace buffer sizes
When the system boots up, the trace buffer is small to conserve memory.
It is only two pages per online CPU. When the tracer is used, it expands
to the default value.
This can confuse the user if they look at the buffer size and see only
7, but then later they see 1408.
# cat /debug/tracing/buffer_size_kb
7
# echo sched_switch > /debug/tracing/current_tracer
# cat /debug/tracing/buffer_size_kb
1408
This patch tries to help remove this confustion by showing that the
buffer has not been expanded.
# cat /debug/tracing/buffer_size_kb
7 (expanded: 1408)
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: speed up and remove possible races
The get_online_cpus was added to the ring buffer because the original
design would free the ring buffer on a CPU that was being taken
off line. The final design kept the ring buffer around even when the
CPU was taken off line. This is to allow a user to still read the
information on that ring buffer.
Most of the get_online_cpus are no longer needed since the ring buffer will
not disappear from the use cases.
Reported-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
The hotplug code in the ring buffers is for use with CPU hotplug,
not generic hotplug.
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: prevent races with ring_buffer_expanded
This patch places the expanding of the tracing buffer under the
protection of the trace_types_lock mutex. It is highly unlikely
that there would be any contention, but better safe than sorry.
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: cleanup
Some of the comments about the trace buffer resizing is gobbledygook.
And I wonder why people question if I'm a native English speaker.
This patch makes the comments make a bit more sense.
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: cleanup
The naming clashes with upcoming softirq tracepoints, so rename the
APIs to lockdep_*().
Requested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild-fixes:
kbuild: remove unused -r option for module-init-tool depmod
kbuild: fix 'make rpm' when CONFIG_LOCALVERSION_AUTO=y and using SCM tree
kbuild: fix mkspec to cleanup RPM_BUILD_ROOT
kbuild: fix C libary confusion in unifdef.c due to getline()
* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus:
cpumask: mm_cpumask for accessing the struct mm_struct's cpu_vm_mask.
cpumask: tsk_cpumask for accessing the struct task_struct's cpus_allowed.
* 'hwmon-for-linus' of git://jdelvare.pck.nerim.net/jdelvare-2.6:
hwmon: (f75375s) Remove unnecessary and confusing initialization
hwmon: (it87) Properly decode -128 degrees C temperature
hwmon: (lm90) Document support for the MAX6648/6692 chips
hwmon: (abituguru3) Fix I/O error handling
Trivial patch to fix bad links in the ext2 and ext3 documentation.
Signed-off-by: Jody McIntyre <scjody@sun.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'fixes-20090312' of git://git.kernel.org/pub/scm/linux/kernel/git/willy/pci:
PCIe: portdrv: call pci_disable_device during remove
pci: Fix typo in message while disabling HT MSI mapping
pci: don't disable too many HT MSI mapping
powerpc/pseries: The RPA PCI hotplug driver depends on EEH
PCIe: AER: during disable, check subordinate before walking
PCI: Add PCI quirk to disable L0s ASPM state for 82575 and 82598
STag zero is a special STag that allows consumers to access any bus
address without registering memory. The nes driver unfortunately
allows STag zero to be used even with QPs created by unprivileged
userspace consumers, which means that any process with direct verbs
access to the nes device can read and write any memory accessible to
the underlying PCI device (usually any memory in the system). Such
access is usually given for cluster software such as MPI to use, so
this is a local privilege escalation bug on most systems running this
driver.
The driver was using STag zero to receive the last streaming mode
data; to allow STag zero to be disabled for unprivileged QPs, the
driver now registers a special MR for this data.
Cc: <stable@kernel.org>
Signed-off-by: Faisal Latif <faisal.latif@intel.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There was a report of a data corruption
http://lkml.org/lkml/2008/11/14/121. There is a script included to
reproduce the problem.
During testing, I encountered a number of strange things with ext3, so I
tried ext2 to attempt to reduce complexity of the problem. I found that
fsstress would quickly hang in wait_on_inode, waiting for I_LOCK to be
cleared, even though instrumentation showed that unlock_new_inode had
already been called for that inode. This points to memory scribble, or
synchronisation problme.
i_state of I_NEW inodes is not protected by inode_lock because other
processes are not supposed to touch them until I_LOCK (and I_NEW) is
cleared. Adding WARN_ON(inode->i_state & I_NEW) to sites where we modify
i_state revealed that generic_sync_sb_inodes is picking up new inodes from
the inode lists and passing them to __writeback_single_inode without
waiting for I_NEW. Subsequently modifying i_state causes corruption. In
my case it would look like this:
CPU0 CPU1
unlock_new_inode() __sync_single_inode()
reg <- inode->i_state
reg -> reg & ~(I_LOCK|I_NEW) reg <- inode->i_state
reg -> inode->i_state reg -> reg | I_SYNC
reg -> inode->i_state
Non-atomic RMW on CPU1 overwrites CPU0 store and sets I_LOCK|I_NEW again.
Fix for this is rather than wait for I_NEW inodes, just skip over them:
inodes concurrently being created are not subject to data integrity
operations, and should not significantly contribute to dirty memory
either.
After this change, I'm unable to reproduce any of the added warnings or
hangs after ~1hour of running. Previously, the new warnings would start
immediately and hang would happen in under 5 minutes.
I'm also testing on ext3 now, and so far no problems there either. I
don't know whether this fixes the problem reported above, but it fixes a
real problem for me.
Cc: "Jorge Boncompte [DTI2]" <jorge@dti2.net>
Reported-by: Adrian Hunter <ext-adrian.hunter@nokia.com>
Cc: Jan Kara <jack@suse.cz>
Cc: <stable@kernel.org>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Even when page reclaim is under mem_cgroup, # of scan page is determined by
status of global LRU. Fix that.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
No software visible difference from revision A.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Samuel Ortiz <sameo@openedhand.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently we disable the Acer WMI backlight device if there is no ACPI
backlight device. As a result, we end up with no backlight device at all.
We should instead disable it if there is an ACPI device, as the other
laptop drivers do. This regression was introduced in febf2d9 ("Acer-WMI:
fingers off backlight if video.ko is serving this functionality").
Each laptop driver with backlight support got a similar change around
febf2d9. The changes to the other drivers look correct; see e.g.
a598c82f for a similar but correct change. The regression is also in
2.6.28.
Signed-off-by: Michael Spang <mspang@csclub.uwaterloo.ca>
Acked-by: Thomas Renninger <trenn@suse.de>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Carlos Corbacho <carlos@strangeworlds.co.uk>
Cc: Len Brown <len.brown@intel.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: <stable@kernel.org> [2.6.28.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The s3cmci driver is calling s3c2410_dma_config with incorrect data for
the DCON register. The S3C2410_DCON_HWTRIG is implicit in the channel
configuration and the device selection of S3C2410_DCON_CH0_SDI is
incorrect as the DMA system may not select channel 0.
Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Acked-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Unfortunately, Linux Foundation funding for my work on
man-pages/testing/doc under the auspices of the LF documentation
fellowship unfortunately ran out a short while ago (after earlier attempts
to seek funding, only Google stepped forward with a bit of further funding
for the position), so the patch below acknowledges something closer to
reality.
Unfortunately, there will (probably very) soon be a further downgrade from
"Maintained" to "Odd Fixes" or "Orphan", unless some funding miracle
occurs. So, if anyone is looking to become man-pages maintainer, there
may soon be an opening (okay, don't trample me in the rush ;-).)
Signed-off-by: Michael Kerrisk <mtk.manpages@googlemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In sget(), destroy_super(s) is called with s->s_umount held, which makes
lockdep unhappy.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If the second fasync_helper() fails, pipe_rdwr_fasync() returns the error
but leaves the file on ->fasync_readers.
This was always wrong, but since 233e70f422
"saner FASYNC handling on file close" we have the new problem. Because in
this case setfl() doesn't set FASYNC bit, __fput() will not do
->fasync(0), and we leak fasync_struct with ->fa_file pointing to the
freed file.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
W1 master implementations are expected to return 0 or 1 from their
read_bit() function. However, not all platforms do return these values
from gpio_get_value() - namely PXAs won't. Hence the w1 gpio-master needs
to break the result down to 0 or 1 itself.
Signed-off-by: Daniel Mack <daniel@caiaq.de>
Cc: Ville Syrjala <syrjala@sci.fi>
Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix the following warning on x86_64:
LD vmlinux.o
MODPOST vmlinux.o
WARNING: vmlinux: 'memcpy' exported twice. Previous export was in vmlinux
For x86_64, this symbol is already exported from arch/um/sys-x86_64/ksyms.c.
Reported-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
Tested-by: Boaz Harrosh <bharrosh@panasas.com>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It is currently impossible to run a user-mode linux machine inside another
user-mode linux (UML on UML). It breaks after a few instructions. When
it tries to check whether SYSEMU is installed (the inner) UML receives an
inconsistent result (from the outer UML).
This is the output of a broken attempt:
$ ./linux mem=256m ubd0=cow
Locating the bottom of the address space ... 0x0
Locating the top of the address space ... 0xc0000000
Core dump limits :
soft - 0
hard - NONE
Checking that ptrace can change system call numbers...OK
Checking ptrace new tags for syscall emulation...unsupported
Checking syscall emulation patch for ptrace...check_sysemu : expected SIGTRAP, got status = 256
$
The problem is the following:
PTRACE_SYSCALL/SINGLESTEP is currently managed inside arch_ptrace for ARCH=um.
PTRACE_SYSEMU/SUSEMU_SINGLESTEP is not captured in arch_ptrace's switch,
therefore it is erroneously passed back to ptrace_request (in
kernel/ptrace).
This simple patch simply forces ptrace to return an error on
PTRACE_SYSEMU/SUSEMU_SINGLESTEP as it is unsupported on ARCH=um, and fixes
the problem.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Renzo Davoli <renzo@cs.unibo.it>
Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The PCIe port driver calls pci_enable_device() during probe but
never calls pci_disable_device() during remove.
Cc: stable@kernel.org
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Prakash's system needs MSI disabled on some bridges, but not all.
This seems to be the minimal fix for 2.6.29, but should be replaced
during 2.6.30.
Signed-off-by: Prakash Punnoor <prakash@punnoor.de>
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
The RPA PCI hotplug driver calls EEH routines, so should depend on
EEH. Also PPC_PSERIES implies PPC64, so remove that.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Commit 47a8b0cc (Enable PCIe AER only after checking firmware
support) wants to walk the PCI bus in the remove path to disable
AER, and calls pci_walk_bus for downstream bridges.
Unfortunately, in the remove path, we remove devices and bridges
in a depth-first manner, starting with the furthest downstream
bridge and working our way backwards.
The furthest downstream bridges will not have a dev->subordinate,
and we hit a NULL deref in pci_walk_bus.
Check for dev->subordinate first before attempting to walk the
PCI hierarchy below us.
Acked-by: Andrew Patterson <andrew.patterson@hp.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
This patch is intended to disable L0s ASPM link state for 82598 (ixgbe)
parts due to the fact that it is possible to corrupt TX data when coming
back out of L0s on some systems. The workaround had been added for 82575
(igb) previously, but did not use the ASPM api. This quirk uses the ASPM
api to prevent the ASPM subsystem from re-enabling the L0s state.
Instead of adding the fix in igb to the ixgbe driver as well it was
decided to move it into a pci quirk. It is necessary to move the fix out
of the driver and into a pci quirk in order to prevent the issue from
occuring prior to driver load to handle the possibility of the device being
passed to a VM via direct assignment.
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
CC: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
* 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus:
MIPS: IP27: Enable RAID5 module
MIPS: TXx9: update defconfigs
MIPS: NEC VR5500 processor support fixup
MIPS: Fix build of non-CONFIG_SYSVIPC version of sys_32_ipc
f75375_probe calls i2c_get_clientdata to initialize the data pointer,
but there isn't yet any client data to get, and the value is never
used before the variable is assigned a new value seven lines later.
The call doesn't hurt anything and wastes only a couple of cycles.
The reason to fix it is because this module serves as an example to
hackers writing new hwmon drivers, and this part of the example is
confusing.
Signed-off-by: Andrew Klossner <andrew@cesa.opbu.xerox.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
The it87 driver is reporting -128 degrees C as +128 degrees C.
That's not a terribly likely temperature value but let's still
get it right, especially when it simplifies the code.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Update documentation to prevent further confusion/duplication.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Fix a logic bug reported by Roel Kluin, by rewriting the error
handling code in a clearer way.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Roel Kluin <roel.kluin@gmail.com>
Acked-by: Alistair John Strachan <alistair@devzero.co.uk>
Acked-by: Hans de Goede <hdegoede@redhat.com>
This allows us to change the representation (to a dangling bitmap or
cpumask_var_t) without breaking all the callers: they can use
mm_cpumask() now and won't see a difference as the changes roll into
linux-next.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This allows us to change the representation (to a dangling bitmap or
cpumask_var_t) without breaking all the callers: they can use
tsk_cpumask() now and won't see a difference as the changes roll into
linux-next.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
The corrupted filesystem patch added a check against zlib trying to
output too much data in the presence of data corruption. This check
triggered if zlib_inflate asked to be called again (Z_OK) with
avail_out == 0 and no more output buffers available. This check proves
to be rather dumb, as it incorrectly catches the case where zlib has
generated all the output, but there are still input bytes to be processed.
This patch does a number of things. It removes the original check and
replaces it with code to not move to the next output buffer if there
are no more output buffers available, relying on zlib to error if it
wants an extra output buffer in the case of data corruption. It
also replaces the Z_NO_FLUSH flag with the more correct Z_SYNC_FLUSH
flag, and makes the error messages more understandable to
non-technical users.
Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
Reported-by: Stefan Lippers-Hollmann <s.L-H@gmx.de>
Impact: save on memory
Currently, a ring buffer was allocated for each "possible_cpus". On
some systems, this is the same as NR_CPUS. Thus, if a system defined
NR_CPUS = 64 but it only had 1 CPU, we could have possibly 63 useless
ring buffers taking up space. With a default buffer of 3 megs, this
could be quite drastic.
This patch changes the ring buffer code to only allocate ring buffers
for online CPUs. If a CPU goes off line, we do not free the buffer.
This is because the user may still have trace data in that buffer
that they would like to look at.
Perhaps in the future we could add code to delete a ring buffer if
the CPU is offline and the ring buffer becomes empty.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: fix to task live locking on reading trace_pipe on one CPU
The same code is used for both trace_pipe (all CPUS) and the per_cpu
trace_pipe file. When there is no data to read, it will check for
signals and wait on the trace wait queue.
The problem happens with the per_cpu wait. The trace_wait code checks
all CPUs. Thus, if there's data in another CPU buffer, then it will
exit the wait, without checking for signals or waiting on the wait queue.
It would then try to read the empty buffer, and since that will just
return nothing, then it will try to wait again. Unfortunately, that will
again fail due to there still being data in the other buffers. This
ends up with a live lock for the task.
This patch fixes the trace_wait to be aware that the iterator may only
be waiting on a single buffer.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
To save memory, the tracer ring buffers are set to a minimum.
The activating of a trace expands the ring buffer size. This patch
adds this expanding, when an event is activated.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: less memory impact on systems not using tracer
When the kernel boots up that has tracing configured, it allocates
the default size of the ring buffer. This currently happens to be
1.4Megs per possible CPU. This is quite a bit of wasted memory if
the system is never using the tracer.
The current solution is to keep the ring buffers to a minimum size
until the user uses them. Once a tracer is piped into the current_tracer
the ring buffer will be expanded to the default size. If the user
changes the size of the ring buffer, it will take the size given
by the user immediately.
If the user adds a "ftrace=" to the kernel command line, then the ring
buffers will be set to the default size on initialization.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
* 'for-linus' of git://oss.sgi.com/xfs/xfs:
xfs: only issues a cache flush on unmount if barriers are enabled
xfs: prevent lockdep false positive in xfs_iget_cache_miss
xfs: prevent kernel crash due to corrupted inode log format
