People are adding `noinline' in various places to prevent excess stack
consumption due to gcc inlining. But once this is done, it is quite unobvious
why the `noinline' is present in the code. We can comment each and every
site, or we can use noinline_for_stack.
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Correct error paths in probe function.
The probe function enables mmio mode so it important to disable the mmio
mode before exiting the probe function. Otherwise, the console is left in
unusable state (garbled fonts at least, lock up at worst).
[akpm@linux-foundation.org: cleanups]
Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Rename Memory Controller to Memory Resource Controller. Reflect the same
changes in the CONFIG definition for the Memory Resource Controller. Group
together the config options for Resource Counters and Memory Resource
Controller.
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.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>
Move kprobes examples from Documentation/kprobes.txt to under samples/.
Patch originally by Randy Dunlap.
o Updated the patch to apply on 2.6.25-rc3
o Modified examples code to build on multiple architectures. Currently,
the kprobe and jprobe examples code works for x86 and powerpc
o Cleaned up unneeded #includes
o Cleaned up Kconfig per Sam Ravnborg's suggestions to fix build break
on archs that don't have kretprobes
o Implemented suggestions by Mathieu Desnoyers on CONFIG_KRETPROBES
o Included Andrew Morton's cleanup based on x86-git
o Modified kretprobe_example to act as a arch-agnostic module to
determine routine execution times:
Use 'modprobe kretprobe_example func=<func_name>' to determine
execution time of func_name in nanoseconds.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add CONFIG_HAVE_KRETPROBES to the arch/<arch>/Kconfig file for relevant
architectures with kprobes support. This facilitates easy handling of
in-kernel modules (like samples/kprobes/kretprobe_example.c) that depend on
kretprobes being present in the kernel.
Thanks to Sam Ravnborg for helping make the patch more lean.
Per Mathieu's suggestion, added CONFIG_KRETPROBES and fixed up dependencies.
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
VT notifier callbacks need to be aware of console switches. This is already
partially done from console_callback(), but at that time fg_console, cursor
positions, etc. are not yet updated and hence screen readers fetch the old
values.
This adds an update notify after all of the values are updated in
redraw_screen(vc, 1).
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some oprofile results obtained while using tbench on a 2x2 cpu machine were
very surprising.
For example, loopback_xmit() function was using high number of cpu cycles
to perform the statistic updates, supposed to be real cheap since they use
percpu data
pcpu_lstats = netdev_priv(dev);
lb_stats = per_cpu_ptr(pcpu_lstats, smp_processor_id());
lb_stats->packets++; /* HERE : serious contention */
lb_stats->bytes += skb->len;
struct pcpu_lstats is a small structure containing two longs. It appears
that on my 32bits platform, alloc_percpu(8) allocates a single cache line,
instead of giving to each cpu a separate cache line.
Using the following patch gave me impressive boost in various benchmarks
( 6 % in tbench)
(all percpu_counters hit this bug too)
Long term fix (ie >= 2.6.26) would be to let each CPU allocate their own
block of memory, so that we dont need to roudup sizes to L1_CACHE_BYTES, or
merging the SGI stuff of course...
Note : SLUB vs SLAB is important here to *show* the improvement, since they
dont have the same minimum allocation sizes (8 bytes vs 32 bytes). This
could very well explain regressions some guys reported when they switched
to SLUB.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix NULL pointer dereference in fsync_buffers_list() introduced by recent fix
of races in private_list handling. Since bh->b_assoc_map has been cleared in
__remove_assoc_queue() we should really use original value stored in the
'mapping' variable.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
jiffies subtraction may cause an overflow problem. It should be using
time_after().
[akpm@linux-foundation.org: include jiffies.h]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Keith Mannthey said:
The parameter hotadd_percent is setup right but there is a "Malformed
early option 'numa'" message.
Rusty Russell said:
This happens when the function registered with early_param() returns
non-zero. __setup() functions return 1 if OK, module_param() and
early_param() return 0 or a -ve error code.
For instance:
Linux version 2.6.25-rc3-t (raa@steel) (gcc version 4.1.3 20070929 (prerelease) (Ubuntu 4.1.2-16ubuntu2)) #22 SMP PREEMPT Tue Feb 26
BIOS-provided physical RAM map:
BIOS-e820: 0000000000000000 - 00000000000a0000 (usable)
BIOS-e820: 00000000000f0000 - 0000000000100000 (reserved)
BIOS-e820: 0000000000100000 - 000000003fff0000 (usable)
BIOS-e820: 000000003fff0000 - 000000003fff3000 (ACPI NVS)
BIOS-e820: 000000003fff3000 - 0000000040000000 (ACPI data)
BIOS-e820: 00000000fec00000 - 0000000100000000 (reserved)
Malformed early option 'loglevel'
127MB HIGHMEM available.
896MB LOWMEM available.
Command line:
BOOT_IMAGE=2.6.25-t ro root=809 ro console=ttyS0,57600n8 console=tty0 loglevel=5
Acked-by: Yinghai Lu <yhlu.kernel@gmai.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Keith Mannthey <kmannth@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This makes the user_regset-based core dump code call user_regset writeback
hooks when available. This is necessary groundwork to allow IA64 to set
CORE_DUMP_USE_REGSET.
Cc: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a <linux/gpio.h> defining fail/warn stubs for GPIO calls on platforms that
don't support the GPIO programming interface. That includes the arch-specific
implementation glue otherwise.
This facilitates a new model for GPIO usage: drivers that can use GPIOs if
they're available, but don't require them. One example of such a driver is
NAND driver for various FreeScale chips. On platforms update with GPIO
support, they can be used instead of a worst-case delay to verify that the
BUSY signal is off.
(Also includes a couple minor unrelated doc updates.)
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This adds basic get/set time support for the Seiko Instruments S-35390A.
This chip communicates using I2C and is used on the QNAP TS-109/TS-209 NAS
devices.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Byron Bradley <byron.bbradley@gmail.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
Acked-by: David Brownell <david-b@pacbell.net>
Tested-by: Tim Ellis <tim@ngndg.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The memory controller has a requirement that while writing values, we need
to use echo -n. This patch fixes the problem and makes the UI more consistent.
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.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>
Commit 2f569afd9c
(CONFIG_HIGHPTE vs. sub-page page tables) introduced use of
inc_zone_page_state and dec_zone_page_state in include/linux/mm.h.
Those are defined in include/linux/vmstat.h, but after it includes
mm.h, making it impossible to include vmstat.h since inc_zone_page_state
and dec_zone_page_state then would be undefined.
arch/cris/arch-v10/kernel/time.c does just this, which makes the
CRIS v10 build break with the following error:
...
CC arch/cris/arch-v10/kernel/time.o
In file included from include/linux/vmstat.h:7,
from arch/cris/arch-v10/kernel/time.c:17:
include/linux/mm.h: In function 'pgtable_page_ctor':
include/linux/mm.h:902: error: implicit declaration of function 'inc_zone_page_state'
include/linux/mm.h: In function 'pgtable_page_dtor':
include/linux/mm.h:908: error: implicit declaration of function 'dec_zone_page_state'
make[2]: *** [arch/cris/arch-v10/kernel/time.o] Error 1
make[1]: *** [arch/cris/arch-v10/kernel] Error 2
make: *** [sub-make] Error 2
...
By changing kernel/time.c to include linux/mm.h, the build succeeds.
Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Mikael Starvik <mikael.starvik@axis.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Thomas Lehmann <thomas.lehmann@alumni.tu-berlin.de> verified that this
entry works.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This version brings a number of minor fixes updating the type detector and
the unary tracker. It also brings a few small fixes for false positives.
It also reverts the --file warning. Of note:
- limit CVS checks to added lines
- improved type detections
- fixes to the unary tracker
Andy Whitcroft (13):
Version: 0.15
EXPORT_SYMBOL checks need to accept array variables
export checks must match DECLARE_foo and LIST_HEAD
possible types: cleanup debugging missing line
values: track values through preprocessor conditional paths
typeof is actually a type
possible types: detect definitions which cross lines
values: include line numbers on value debug information
values: ensure we find correctly record pending brackets
values: simplify the brace history stack
CVS keyword checks should only apply to added lines
loosen spacing for comments
allow braces for single statement blocks with multiline conditionals
Harvey Harrison (1):
checkpatch: remove fastcall
Ingo Molnar (1):
checkpatch.pl: revert wrong --file message
Uwe Kleine-Koenig (1):
fix typo "goot" -> "good"
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Cc: Joel Schopp <jschopp@austin.ibm.com>
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>
The documentation says the default value of notify_on_release of a child
cgroup is inherited from its parent, which is reasonable, but the
implementation just sets the flag disabled.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
P4 has been coming out as CPU_FAMILY=4 instead of 6: fix MPENTIUM4 typo.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mfasheh/ocfs2:
[PATCH] fs/ocfs2/aops.c: Correct use of ! and &
[2.6 patch] ocfs2: make dlm_do_assert_master() static
[2.6 patch] make ocfs2_downconvert_thread() static
[2.6 patch] fs/ocfs2/: possible cleanups
[PATCH] ocfs2: le*_add_cpu conversion
ocfs2: Fix writeout in ocfs2_data_convert_worker()
ocfs2: Enable localalloc for local mounts
* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/async_tx:
ioat: fix 'ack' handling, driver must ensure that 'ack' is zero
dmaengine: fix sparse warning
fsldma: do not cleanup descriptors in hardirq context
dmaengine: add driver for Freescale MPC85xx DMA controller
Original patch from Tejun Heo <htejun@gmail.com> but should use ->extra_len
and not ->data_len, as we would then overshoot the original request size.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-x86:
x86/xen: fix DomU boot problem
x86: not set node to cpu_to_node if the node is not online
x86, i387: fix ptrace leakage using init_fpu()
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/avi/kvm:
x86: disable KVM for Voyager and friends
KVM: VMX: Avoid rearranging switched guest msrs while they are loaded
KVM: MMU: Fix race when instantiating a shadow pte
KVM: Route irq 0 to vcpu 0 exclusively
KVM: Avoid infinite-frequency local apic timer
KVM: make MMU_DEBUG compile again
KVM: move alloc_apic_access_page() outside of non-preemptable region
KVM: SVM: fix Windows XP 64 bit installation crash
KVM: remove the usage of the mmap_sem for the protection of the memory slots.
KVM: emulate access to MSR_IA32_MCG_CTL
KVM: Make the supported cpuid list a host property rather than a vm property
KVM: Fix kvm_arch_vcpu_ioctl_set_sregs so that set_cr0 works properly
KVM: SVM: set NM intercept when enabling CR0.TS in the guest
KVM: SVM: Fix lazy FPU switching
Initialize 'ack' to zero in case the descriptor has been recycled.
Prevents "kernel BUG at crypto/async_tx/async_xor.c:185!"
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Shannon Nelson <shannon.nelson@intel.com>
Cc: stable@kernel.org
"Cleaning" descriptors involves calling pending callbacks and clients
assume that their callback will only ever happen in softirq context.
Delay cleanup to the tasklet.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Zhang Wei <wei.zhang@freescale.com>
The driver implements DMA engine API for Freescale MPC85xx DMA controller,
which could be used by devices in the silicon. The driver supports the
Basic mode of Freescale MPC85xx DMA controller. The MPC85xx processors
supported include MPC8540/60, MPC8555, MPC8548, MPC8641 and so on.
The MPC83xx(MPC8349, MPC8360) are also supported.
[kamalesh@linux.vnet.ibm.com: build fix]
[dan.j.williams@intel.com: merge mm fixes, rebase on async_tx-2.6.25]
Signed-off-by: Zhang Wei <wei.zhang@freescale.com>
Signed-off-by: Ebony Zhu <ebony.zhu@freescale.com>
Acked-by: Kumar Gala <galak@gate.crashing.org>
Cc: Shannon Nelson <shannon.nelson@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
The following commits cause a number of regressions:
commit 58e2d4ca58
Author: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Date: Fri Jan 25 21:08:00 2008 +0100
sched: group scheduling, change how cpu load is calculated
commit 6b2d770026
Author: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Date: Fri Jan 25 21:08:00 2008 +0100
sched: group scheduler, fix fairness of cpu bandwidth allocation for task groups
Namely:
- very frequent wakeups on SMP, reported by PowerTop users.
- cacheline trashing on (large) SMP
- some latencies larger than 500ms
While there is a mergeable patch to fix the latter, the former issues
are not fixable in a manner suitable for .25 (we're at -rc3 now).
Hence we revert them and try again in v2.6.26.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
CC: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Tested-by: Alexey Zaytsev <alexey.zaytsev@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Construct Xen guest e820 map with a hole between 640K-1M.
It's pure luck that Xen kernels have gotten away with it in the past.
The patch below seems like the right thing to do. It certainly boots in
a domU without the DMI problem (without any of the other related patches
such as Alexander's).
Signed-off-by: Ian Campbell <ijc@hellion.org.uk>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Tested-by: Mark McLoughlin <markmc@redhat.com>
Acked-by: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
resolve boot problem reported by Mel Gorman:
http://lkml.org/lkml/2008/2/13/404
init_cpu_to_node will use cpu->apic (from MADT or mptable) and
apic->node(from SRAT or AMD config space with k8_bus_64.c) to have
cpu->node mapping, and later identify_cpu will overwrite them
again...(with nearby_node...)
this patch checks if the node is online, otherwise it will not
update cpu_node map. so keep cpu_node map to online node before
identify_cpu..., to prevent possible error.
Signed-off-by: Yinghai Lu <yinghai.lu@sun.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
This bug got introduced by the recent i387 merge:
commit 4421011120
Author: Roland McGrath <roland@redhat.com>
Date: Wed Jan 30 13:31:50 2008 +0100
x86: x86 i387 user_regset
Current usage of unlazy_fpu() in ptrace specific routines is wrong.
unlazy_fpu() will not init fpu if the task never used math. So the
ptrace calls can expose the parent tasks FPU data in some cases.
Replace it with the init_fpu() which will init the math state, if the
task never used math before.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
block: fix blkdev_issue_flush() not detecting and passing EOPNOTSUPP back
block: fix shadowed variable warning in blk-map.c
block: remove extern on function definition
cciss: remove READ_AHEAD define and use block layer defaults
make cdrom.c:check_for_audio_disc() static
block/genhd.c: proper externs
unexport blk_rq_map_user_iov
unexport blk_{get,put}_queue
block/genhd.c: cleanups
proper prototype for blk_dev_init()
block/blk-tag.c should #include "blk.h"
Fix DMA access of block device in 64-bit kernel on some non-x86 systems with 4GB or upper 4GB memory
block: separate out padding from alignment
block: restore the meaning of rq->data_len to the true data length
resubmit: cciss: procfs updates to display info about many
splice: only return -EAGAIN if there's hope of more data
block: fix kernel-docbook parameters and files
m68k{,nommu}: Wire up the new timerfd syscalls, which were introduced in
commit 4d672e7ac7 ("timerfd: new timerfd API").
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The FEC driver has a common interrupt handler for all interrupt event
types. It is raised on a number of distinct interrupt vectors.
This handler can't be re-entered while processing an interrupt, so
make sure all requested vectors are flagged as IRQF_DISABLED.
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Need a declaration of do_IRQ for the 68328 interrupt handling code.
It is common to all m68knommu targets, so a common declaration makes
sense.
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6:
[CIFS] remove unused variable
[CIFS] consolidate duplicate code in posix/unix inode handling
[CIFS] fix build break when proc disabled
[CIFS] factoring out common code in get_inode_info functions
[CIFS] fix prepath conversion when server supports posix paths
[CIFS] Only convert / when server does not support posix paths
[CIFS] Fix mixed case name in structure dfs_info3_param
[CIFS] fixup prefixpaths which contain multiple path components
[CIFS] fix typo
[CIFS] patch to fix incorrect encoding of number of aces on set mode
[CIFS] Fix typo in quota operations
[CIFS] clean up some hard to read ifdefs
[CIFS] reduce checkpatch warnings
[CIFS] fix warning in cifs_spnego.c
This changes the "freezer" code used by suspend/hibernate in its treatment
of tasks in TASK_STOPPED (job control stop) and TASK_TRACED (ptrace) states.
As I understand it, the intent of the "freezer" is to hold all tasks
from doing anything significant. For this purpose, TASK_STOPPED and
TASK_TRACED are "frozen enough". It's possible the tasks might resume
from ptrace calls (if the tracer were unfrozen) or from signals
(including ones that could come via timer interrupts, etc). But this
doesn't matter as long as they quickly block again while "freezing" is
in effect. Some minor adjustments to the signal.c code make sure that
try_to_freeze() very shortly follows all wakeups from both kinds of
stop. This lets the freezer code safely leave stopped tasks unmolested.
Changing this fixes the longstanding bug of seeing after resuming from
suspend/hibernate your shell report "[1] Stopped" and the like for all
your jobs stopped by ^Z et al, as if you had freshly fg'd and ^Z'd them.
It also removes from the freezer the arcane special case treatment for
ptrace'd tasks, which relied on intimate knowledge of ptrace internals.
Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Most classic Pentiums don't have hardware virtualization extension,
and building kvm with Voyager, Visual Workstation, or NUMAQ
generates spurious failures.
Signed-off-by: Avi Kivity <avi@qumranet.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
KVM tries to run as much as possible with the guest msrs loaded instead of
host msrs, since switching msrs is very expensive. It also tries to minimize
the number of msrs switched according to the guest mode; for example,
MSR_LSTAR is needed only by long mode guests. This optimization is done by
setup_msrs().
However, we must not change which msrs are switched while we are running with
guest msr state:
- switch to guest msr state
- call setup_msrs(), removing some msrs from the list
- switch to host msr state, leaving a few guest msrs loaded
An easy way to trigger this is to kexec an x86_64 linux guest. Early during
setup, the guest will switch EFER to not include SCE. KVM will stop saving
MSR_LSTAR, and on the next msr switch it will leave the guest LSTAR loaded.
The next host syscall will end up in a random location in the kernel.
Fix by reloading the host msrs before changing the msr list.
Signed-off-by: Avi Kivity <avi@qumranet.com>
For improved concurrency, the guest walk is performed concurrently with other
vcpus. This means that we need to revalidate the guest ptes once we have
write-protected the guest page tables, at which point they can no longer be
modified.
The current code attempts to avoid this check if the shadow page table is not
new, on the assumption that if it has existed before, the guest could not have
modified the pte without the shadow lock. However the assumption is incorrect,
as the racing vcpu could have modified the pte, then instantiated the shadow
page, before our vcpu regains control:
vcpu0 vcpu1
fault
walk pte
modify pte
fault in same pagetable
instantiate shadow page
lookup shadow page
conclude it is old
instantiate spte based on stale guest pte
We could do something clever with generation counters, but a test run by
Marcelo suggests this is unnecessary and we can just do the revalidation
unconditionally. The pte will be in the processor cache and the check can
be quite fast.
Signed-off-by: Avi Kivity <avi@qumranet.com>
Some Linux versions allow the timer interrupt to be processed by more than
one cpu, leading to hangs due to tsc instability. Work around the issue
by only disaptching the interrupt to vcpu 0.
Problem analyzed (and patch tested) by Sheng Yang.
Signed-off-by: Avi Kivity <avi@qumranet.com>
