| Age | Commit message (Collapse) | Author | Files | Lines |
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'timers/urgent' into timers/core
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One of my past fixes to this code introduced a different new bug.
When using 32-bit "int $0x80" entry for a bogus syscall number,
the return value is not correctly set to -ENOSYS. This only happens
when neither syscall-audit nor syscall tracing is enabled (i.e., never
seen if auditd ever started). Test program:
/* gcc -o int80-badsys -m32 -g int80-badsys.c
Run on x86-64 kernel.
Note to reproduce the bug you need auditd never to have started. */
#include <errno.h>
#include <stdio.h>
int
main (void)
{
long res;
asm ("int $0x80" : "=a" (res) : "0" (99999));
printf ("bad syscall returns %ld\n", res);
return res != -ENOSYS;
}
The fix makes the int $0x80 path match the sysenter and syscall paths.
Reported-by: Dmitry V. Levin <ldv@altlinux.org>
Signed-off-by: Roland McGrath <roland@redhat.com>
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Implement Linus's suggestion: introduce the hpet_cnt_ahead()
helper function to compare hpet time values - like other
wrapping counter comparisons are abstracted away elsewhere.
(jiffies, ktime_t, etc.)
Reported-by: Kirill Korotaev <dev@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Prevent kprobes from catching spurious faults which will cause infinite
recursive page-fault and memory corruption by stack overflow.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: <stable@kernel.org> [2.6.28.x]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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There's a small problem with hpet_rtc_reinit function - it checks
for the:
hpet_readl(HPET_COUNTER) - hpet_t1_cmp > 0
to continue increasing both the HPET_T1_CMP (register) and the
hpet_t1_cmp (variable).
But since the HPET_COUNTER is always 32-bit, if the hpet_t1_cmp
is 64-bit this condition will always be FALSE once the latter hits
the 32-bit boundary, and we can have a situation, when we don't
increase the HPET_T1_CMP register high enough.
The result - timer stops ticking, since HPET_T1_CMP becomes less,
than the COUNTER and never increased again.
The solution is (based on Linus's suggestion) to not compare 64-bits
(on 64-bit x86), but to do the comparison on 32-bit signed
integers.
Reported-by: Kirill Korotaev <dev@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Impact: fix to enable APIC for AMD Fam10h on chipsets with a missing/b0rked
ACPI MP table (MADT)
Booting a 32bit kernel on an AMD Fam10h CPU running on chipsets with
missing/b0rked MP table leads to a hang pretty early in the boot process
due to the APIC not being initialized. Fix that by falling back to the
default APIC base address in 32bit code, as it is done in the 64bit
codepath.
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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Impact: Fix race condition
xen_mc_batch has a small preempt race where it takes the address of a
percpu variable immediately before disabling interrupts, thereby
leaving a small window in which we may migrate to another cpu and save
the flags in the wrong percpu variable. Disable interrupts before
saving the old flags in a percpu.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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Impact: Fixes dumpstack and KDB on 64 bits
This re-adds the old stack pointer to the top of the irqstack to help
with unwinding. It was removed in commit d99015b1abbad743aa049b439c1e1dede6d0fa49
as part of the save_args out-of-line work.
Both dumpstack and KDB require this information.
Signed-off-by: Martin Hicks <mort@sgi.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6:
PCI hotplug: Change link order of pciehp & acpiphp
PCI hotplug: fakephp: Allocate PCI resources before adding the device
PCI MSI: Fix undefined shift by 32
PCI PM: Do not wait for buses in B2 or B3 during resume
PCI PM: Power up devices before restoring their state
PCI PM: Fix hibernation breakage on EeePC 701
PCI: irq and pci_ids patch for Intel Tigerpoint DeviceIDs
PCI PM: Fix suspend error paths and testing facility breakage
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Eric Paris reported:
> I have an hp dl785g5 which is unable to successfully run
> 2.6.29-0.66.rc3.fc11.x86_64 or 2.6.29-rc2-next-20090126. During bootup
> (early in userspace daemons starting) I get the below BUG, which quickly
> renders the machine dead. I assume it is because sparse_irq_lock never
> gets released when the BUG kills that task.
Adjust lock sequence when migrating a descriptor with
CONFIG_NUMA_MIGRATE_IRQ_DESC enabled.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'header-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (90 commits)
headers_check fix: x86, swab.h
headers_check fix: x86, sigcontext32.h
headers_check fix: x86, sigcontext.h
headers_check fix: x86, ptrace-abi.h
headers_check fix: x86, mtrr.h
headers_check fix: x86, mce.h
headers_check fix: x86, kvm.h
headers_check fix: x86, e820.h
headers_check fix: linux/rtnetlink.h
headers_check fix: linux/nubus.h
headers_check fix: video/uvesafb.h
headers_check fix: video/sisfb.h
headers_check fix: sound/hdsp.h
headers_check fix: mtd/inftl-user.h
headers_check fix: linux/virtio_net.h
headers_check fix: linux/virtio_console.h
headers_check fix: linux/virtio_blk.h
headers_check fix: linux/videodev.h
headers_check fix: linux/video_encoder.h
headers_check fix: linux/video_decoder.h
...
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, ds, bts: cleanup/fix DS configuration
ring-buffer: reset timestamps when ring buffer is reset
trace: set max latency variable to zero on default
trace: stop all recording to ring buffer on ftrace_dump
trace: print ftrace_dump at KERN_EMERG log level
ring_buffer: reset write when reserve buffer fail
tracing/function-graph-tracer: fix a regression while suspend to disk
ring-buffer: fix alignment problem
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86 setup: fix asm constraints in vesa_store_edid
xen: make sysfs files behave as their names suggest
x86: tone down mtrr_trim_uncached_memory() warning
x86: correct the CPUID pattern for MSR_IA32_MISC_ENABLE availability
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[
mingo@elte.hu: these fixes are a subset of changes cherry-picked from:
git://git.kernel.org:/pub/scm/linux/kernel/git/jejb/voyager-2.6.git
They fix various problems that recent x86 changes caused in the Voyager
subarchitecture: both APIC changes and cpumask changes and certain
cleanups caused subarch assumptions to break.
Most of these changes are obsolete as the subarch code has been removed
from the x86 development tree - but we merge them upstream to make Voyager
build and boot.
]
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Impact: fix potential miscompile (currently believed non-manifest)
As the comment explains, the VBE DDC call can clobber any register.
Tell the compiler about that fact.
Signed-off-by: Andreas Schwab <schwab@suse.de>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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fix the following 'make headers_check' warnings:
usr/include/asm/swab.h:4: include of <linux/types.h> is preferred over <asm/types.h>
usr/include/asm/swab.h:7: found __[us]{8,16,32,64} type without #include <linux/types.h>
Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
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fix the following 'make headers_check' warning:
usr/include/asm/sigcontext32.h:20: found __[us]{8,16,32,64} type without #include <linux/types.h>
Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
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fix the following 'make headers_check' warnings:
usr/include/asm/sigcontext.h:5: include of <linux/types.h> is preferred over <asm/types.h>
usr/include/asm/sigcontext.h:24: found __[us]{8,16,32,64} type without #include <linux/types.h>
Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
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fix the following 'make headers_check' warnings:
usr/include/asm/ptrace-abi.h:86: include of <linux/types.h> is preferred over <asm/types.h>
usr/include/asm/ptrace-abi.h:93: found __[us]{8,16,32,64} type without #include <linux/types.h>
Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
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fix the following 'make headers_check' warning:
usr/include/asm/mtrr.h:61: found __[us]{8,16,32,64} type without #include <linux/types.h>
Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
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fix the following 'make headers_check' warnings:
usr/include/asm/mce.h:7: include of <linux/types.h> is preferred over <asm/types.h>
usr/include/asm/mce.h:29: found __[us]{8,16,32,64} type without #include <linux/types.h>
Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
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fix the following 'make headers_check' warnings:
usr/include/asm/kvm.h:9: include of <linux/types.h> is preferred over <asm/types.h>
usr/include/asm/kvm.h:16: found __[us]{8,16,32,64} type without #include <linux/types.h>
Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
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fix the following 'make headers_check' warning:
usr/include/asm/e820.h:44: found __[us]{8,16,32,64} type without #include <linux/types.h>
Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
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Move DMA-mapping.txt to Documentation/PCI/.
DMA-mapping.txt was supposed to be moved from Documentation/ to
Documentation/PCI/. The 00-INDEX files in those two directories
were updated, along with a few other text files, but the file
itself somehow escaped being moved, so move it and update more
text files and source files with its new location.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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3 points
lguest_asm.S => i386_head.S
LHCALL_BREAK => LHREQ_BREAK
perferred => preferred
Signed-off-by: Atsushi SAKAI <sakaia@jp.fujitsu.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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kerneloops.org is reporting a lot of these warnings that come due to
vmware not setting up any MTRRs for emulated CPUs:
| Reported 709 times (14696 total reports)
| BIOS bug (often in VMWare) where the MTRR's are set up incorrectly
| or not at all
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| This warning was last seen in version 2.6.29-rc2-git1, and first
| seen in 2.6.24.
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| More info:
| http://www.kerneloops.org/searchweek.php?search=mtrr_trim_uncached_memory
Keep a one-liner KERN_INFO about it - so that we have so notice if empty
MTRRs are caused by native hardware/BIOS weirdness.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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This patch adds the Intel Tigerpoint LPC Controller DeviceIDs.
Signed-off-by: Seth Heasley <seth.heasley@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
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* 'i2c-for-linus' of git://jdelvare.pck.nerim.net/jdelvare-2.6:
i2c: Warn on deprecated binding model use
eeprom: More consistent symbol names
eeprom: Move 93cx6 eeprom driver to /drivers/misc/eeprom
spi: Move at25 (for SPI eeproms) to /drivers/misc/eeprom
i2c: Move old eeprom driver to /drivers/misc/eeprom
i2c: Move at24 to drivers/misc/eeprom
i2c: Quilt tree has moved
i2c: Delete many unused adapter IDs
i2c: Delete 10 unused driver IDs
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* git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild-fixes:
kbuild: fix kbuild.txt typos
kbuild: print usage with no arguments in scripts/config
Revert "kbuild: strip generated symbols from *.ko"
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Now that all EEPROM drivers live in the same place, let's harmonize
their symbol names.
Also fix eeprom's dependencies, it definitely needs sysfs, and is no
longer experimental after many years in the kernel tree.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
Cc: David Brownell <dbrownell@users.sourceforge.net>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
debugobjects: add and use INIT_WORK_ON_STACK
rcu: remove duplicate CONFIG_RCU_CPU_STALL_DETECTOR
relay: fix lock imbalance in relay_late_setup_files
oprofile: fix uninitialized use of struct op_entry
rcu: move Kconfig menu
softlock: fix false panic which can occur if softlockup_thresh is reduced
rcu: add __cpuinit to rcu_init_percpu_data()
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
hrtimers: fix inconsistent lock state on resume in hres_timers_resume
time-sched.c: tick_nohz_update_jiffies should be static
locking, hpet: annotate false positive warning
kernel/fork.c: unused variable 'ret'
itimers: remove the per-cpu-ish-ness
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (29 commits)
xen: unitialised return value in xenbus_write_transaction
x86: fix section mismatch warning
x86: unmask CPUID levels on Intel CPUs, fix
x86: work around PAGE_KERNEL_WC not getting WC in iomap_atomic_prot_pfn.
x86: use standard PIT frequency
xen: handle highmem pages correctly when shrinking a domain
x86, mm: fix pte_free()
xen: actually release memory when shrinking domain
x86: unmask CPUID levels on Intel CPUs
x86: add MSR_IA32_MISC_ENABLE bits to <asm/msr-index.h>
x86: fix PTE corruption issue while mapping RAM using /dev/mem
x86: mtrr fix debug boot parameter
x86: fix page attribute corruption with cpa()
Revert "x86: signal: change type of paramter for sys_rt_sigreturn()"
x86: use early clobbers in usercopy*.c
x86: remove kernel_physical_mapping_init() from init section
fix: crash: IP: __bitmap_intersects+0x48/0x73
cpufreq: use work_on_cpu in acpi-cpufreq.c for drv_read and drv_write
work_on_cpu: Use our own workqueue.
work_on_cpu: don't try to get_online_cpus() in work_on_cpu.
...
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Impact: re-enable CPUID unmasking on affected processors
As far as I am capable of discerning from the documentation,
MSR_IA32_MISC_ENABLE should be available for all family 0xf CPUs, as
well as family 6 for model >= 0xd (newer Pentium M).
The documentation on this isn't ideal, so we need to be on the lookout
for errors, still.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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Here function vmi_activate calls a init function activate_vmi , which
causes the following section mismatch warnings:
LD arch/x86/kernel/built-in.o
WARNING: arch/x86/kernel/built-in.o(.text+0x13ba9): Section mismatch
in reference from the function vmi_activate() to the function
.init.text:vmi_time_init()
The function vmi_activate() references
the function __init vmi_time_init().
This is often because vmi_activate lacks a __init
annotation or the annotation of vmi_time_init is wrong.
WARNING: arch/x86/kernel/built-in.o(.text+0x13bd1): Section mismatch
in reference from the function vmi_activate() to the function
.devinit.text:vmi_time_bsp_init()
The function vmi_activate() references
the function __devinit vmi_time_bsp_init().
This is often because vmi_activate lacks a __devinit
annotation or the annotation of vmi_time_bsp_init is wrong.
WARNING: arch/x86/kernel/built-in.o(.text+0x13bdb): Section mismatch
in reference from the function vmi_activate() to the function
.devinit.text:vmi_time_ap_init()
The function vmi_activate() references
the function __devinit vmi_time_ap_init().
This is often because vmi_activate lacks a __devinit
annotation or the annotation of vmi_time_ap_init is wrong.
Fix it by marking vmi_activate() as __init too.
Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Impact: fix boot hang on pre-model-15 Intel CPUs
rdmsrl_safe() does not work in very early bootup code yet, because we
dont have the pagefault handler installed yet so exception section
does not get parsed. rdmsr_safe() will just crash and hang the bootup.
So limit the MSR_IA32_MISC_ENABLE MSR read to those CPU types that
support it.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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In the absence of PAT, PAGE_KERNEL_WC ends up mapping to a memory type that
gets UC behavior even in the presence of a WC MTRR covering the area in
question. By swapping to PAGE_KERNEL_UC_MINUS, we can get the actual
behavior the caller wanted (WC if you can manage it, UC otherwise).
This recovers the 40% performance improvement of using WC in the DRM
to upload vertex data.
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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the RDC and ELAN platforms use slighly different PIT clocks, resulting in
a timex.h hack that changes PIT_TICK_RATE during build time. But if a
tester enables any of these platform support .config options, the PIT
will be miscalibrated on standard PC platforms.
So use one frequency - in a subsequent patch we'll add a quirk to allow
x86 platforms to define different PIT frequencies.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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On -rt we were seeing spurious bad page states like:
Bad page state in process 'firefox'
page:c1bc2380 flags:0x40000000 mapping:c1bc2390 mapcount:0 count:0
Trying to fix it up, but a reboot is needed
Backtrace:
Pid: 503, comm: firefox Not tainted 2.6.26.8-rt13 #3
[<c043d0f3>] ? printk+0x14/0x19
[<c0272d4e>] bad_page+0x4e/0x79
[<c0273831>] free_hot_cold_page+0x5b/0x1d3
[<c02739f6>] free_hot_page+0xf/0x11
[<c0273a18>] __free_pages+0x20/0x2b
[<c027d170>] __pte_alloc+0x87/0x91
[<c027d25e>] handle_mm_fault+0xe4/0x733
[<c043f680>] ? rt_mutex_down_read_trylock+0x57/0x63
[<c043f680>] ? rt_mutex_down_read_trylock+0x57/0x63
[<c0218875>] do_page_fault+0x36f/0x88a
This is the case where a concurrent fault already installed the PTE and
we get to free the newly allocated one.
This is due to pgtable_page_ctor() doing the spin_lock_init(&page->ptl)
which is overlaid with the {private, mapping} struct.
union {
struct {
unsigned long private;
struct address_space *mapping;
};
spinlock_t ptl;
struct kmem_cache *slab;
struct page *first_page;
};
Normally the spinlock is small enough to not stomp on page->mapping, but
PREEMPT_RT=y has huge 'spin'locks.
But lockdep kernels should also be able to trigger this splat, as the
lock tracking code grows the spinlock to cover page->mapping.
The obvious fix is calling pgtable_page_dtor() like the regular pte free
path __pte_free_tlb() does.
It seems all architectures except x86 and nm10300 already do this, and
nm10300 doesn't seem to use pgtable_page_ctor(), which suggests it
doesn't do SMP or simply doesnt do MMU at all or something.
Signed-off-by: Peter Zijlstra <a.p.zijlsta@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: <stable@kernel.org>
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Cleanup the cpuid check for DS configuration.
This also fixes a Corei7 CPUID enumeration bug.
Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Impact: Fix debugobjects warning
debugobject enabled kernels spit out a warning in hpet code due to a
workqueue which is initialized on stack.
Add INIT_WORK_ON_STACK() which calls init_timer_on_stack() and use it
in hpet.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Impact: Fixes crashes with misconfigured BIOSes on XSAVE hardware
Avuton Olrich reported early boot crashes with v2.6.28 and
bisected it down to dc1e35c6e95e8923cf1d3510438b63c600fee1e2
("x86, xsave: enable xsave/xrstor on cpus with xsave support").
If the CPUID limit bit in MSR_IA32_MISC_ENABLE is set, clear it to
make all CPUID information available. This is required for some
features to work, in particular XSAVE.
Reported-and-bisected-by: Avuton Olrich <avuton@gmail.com>
Tested-by: Avuton Olrich <avuton@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
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Impact: None (new bit definitions currently unused)
Add bit definitions for the MSR_IA32_MISC_ENABLE MSRs to
<asm/msr-index.h>.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
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Beschorner Daniel reported:
> hwinfo problem since 2.6.28, showing this in the oops:
> Corrupted page table at address 7fd04de3ec00
Also, PaX Team reported a regression with this commit:
> commit 9542ada803198e6eba29d3289abb39ea82047b92
> Author: Suresh Siddha <suresh.b.siddha@intel.com>
> Date: Wed Sep 24 08:53:33 2008 -0700
>
> x86: track memtype for RAM in page struct
This commit breaks mapping any RAM page through /dev/mem, as the
reserve_memtype() was not initializing the return attribute type and as such
corrupting the PTE entry that was setup with the return attribute type.
Because of this bug, application mapping this RAM page through /dev/mem
will die with "Corrupted page table at address xxxx" message in the kernel
log and also the kernel identity mapping which maps the underlying RAM
page gets converted to UC.
Fix this by initializing the return attribute type before calling
reserve_ram_pages_type()
Reported-by: PaX Team <pageexec@freemail.hu>
Reported-and-tested-by: Beschorner Daniel <Daniel.Beschorner@facton.com>
Tested-and-Acked-by: PaX Team <pageexec@freemail.hu>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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while looking at:
http://bugzilla.kernel.org/show_bug.cgi?id=11541
I realized that the mtrr.show param cannot work, because
the code is processed much too early.
This patch:
- Declares mtrr.show as early_param
- Stays consistent with the previous param (which I doubt
that it ever worked), so mtrr.show=1 would still work
- Declares mtrr_show as initdata
Signed-off-by: Thomas Renninger <trenn@suse.de>
Acked-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Impact: fix sporadic slowdowns and warning messages
This patch fixes a performance issue reported by Linus on his
Nehalem system. While Linus reverted the PAT patch (commit
58dab916dfb57328d50deb0aa9b3fc92efa248ff) which exposed the issue,
existing cpa() code can potentially still cause wrong(page attribute
corruption) behavior.
This patch also fixes the "WARNING: at arch/x86/mm/pageattr.c:560" that
various people reported.
In 64bit kernel, kernel identity mapping might have holes depending
on the available memory and how e820 reports the address range
covering the RAM, ACPI, PCI reserved regions. If there is a 2MB/1GB hole
in the address range that is not listed by e820 entries, kernel identity
mapping will have a corresponding hole in its 1-1 identity mapping.
If cpa() happens on the kernel identity mapping which falls into these holes,
existing code fails like this:
__change_page_attr_set_clr()
__change_page_attr()
returns 0 because of if (!kpte). But doesn't
set cpa->numpages and cpa->pfn.
cpa_process_alias()
uses uninitialized cpa->pfn (random value)
which can potentially lead to changing the page
attribute of kernel text/data, kernel identity
mapping of RAM pages etc. oops!
This bug was easily exposed by another PAT patch which was doing
cpa() more often on kernel identity mapping holes (physical range between
max_low_pfn_mapped and 4GB), where in here it was setting the
cache disable attribute(PCD) for kernel identity mappings aswell.
Fix cpa() to handle the kernel identity mapping holes. Retain
the WARN() for cpa() calls to other not present address ranges
(kernel-text/data, ioremap() addresses)
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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This reverts commit 4217458dafaa57d8e26a46f5d05ab8c53cf64191.
Justin Madru bisected this commit, it was causing weird Firefox
crashes.
The reason is that GCC mis-optimizes (re-uses) the on-stack parameters of
the calling frame, which corrupts the syscall return pt_regs state and
thus corrupts user-space register state.
So we go back to the slightly less clean but more optimization-safe
method of getting to pt_regs. Also add a comment to explain this.
Resolves: http://bugzilla.kernel.org/show_bug.cgi?id=12505
Reported-and-bisected-by: Justin Madru <jdm64@gawab.com>
Tested-by: Justin Madru <jdm64@gawab.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Impact: fix rare (but currently harmless) miscompile with certain configs and gcc versions
Hugh Dickins noticed that strncpy_from_user() was miscompiled
in some circumstances with gcc 4.3.
Thanks to Hugh's excellent analysis it was easy to track down.
Hugh writes:
> Try building an x86_64 defconfig 2.6.29-rc1 kernel tree,
> except not quite defconfig, switch CONFIG_PREEMPT_NONE=y
> and CONFIG_PREEMPT_VOLUNTARY off (because it expands a
> might_fault() there, which hides the issue): using a
> gcc 4.3.2 (I've checked both openSUSE 11.1 and Fedora 10).
>
> It generates the following:
>
> 0000000000000000 <__strncpy_from_user>:
> 0: 48 89 d1 mov %rdx,%rcx
> 3: 48 85 c9 test %rcx,%rcx
> 6: 74 0e je 16 <__strncpy_from_user+0x16>
> 8: ac lods %ds:(%rsi),%al
> 9: aa stos %al,%es:(%rdi)
> a: 84 c0 test %al,%al
> c: 74 05 je 13 <__strncpy_from_user+0x13>
> e: 48 ff c9 dec %rcx
> 11: 75 f5 jne 8 <__strncpy_from_user+0x8>
> 13: 48 29 c9 sub %rcx,%rcx
> 16: 48 89 c8 mov %rcx,%rax
> 19: c3 retq
>
> Observe that "sub %rcx,%rcx; mov %rcx,%rax", whereas gcc 4.2.1
> (and many other configs) say "sub %rcx,%rdx; mov %rdx,%rax".
> Isn't it returning 0 when it ought to be returning strlen?
The asm constraints for the strncpy_from_user() result were missing an
early clobber, which tells gcc that the last output arguments
are written before all input arguments are read.
Also add more early clobbers in the rest of the file and fix 32-bit
usercopy.c in the same way.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
[ since this API is rarely used and no in-kernel user relies on a 'len'
return value (they only rely on negative return values) this miscompile
was never noticed in the field. But it's worth fixing it nevertheless. ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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