This patch removes the assumption that LAPIC entries contain the BSP as its
first entry. This is a slight improvement to the temporary fix submitted by
Suresh Siddha.
- Removes assumption that LAPIC entries contain BSP first.
- Builds x86_acpiid_to_apicid[] and bios_cpu_apicid[] properly with BSP as
first entry.
- Made maxcpus=1 boot on these systems. Since the parsing earlier in
arch/x86_64/kernel/mpparse.c stopped after maxcpus entries, other entries
were not processed, this causes kernel not to boot on these systems.
TBD: x86_acpiid_to_apicid and bios_cpu_apicid[] seem to be exactly the
same. This could be removed, but might need more work to cleanup.
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Collected NMI watchdog fixes.
- Fix call of check_nmi_watchdog
- Remove earlier move of check_nmi_watchdog to later. It does not fix the
race it was supposed to fix fully.
- Remove unused P6 definitions
- Add support for performance counter based watchdog on P4 systems.
This allows to run it only once per second, which saves some CPU time.
Previously it would run at 1000Hz, which was too much.
Code ported from i386
Make this the default on Intel systems.
- Use check_nmi_watchdog with local APIC based nmi
- Fix race in touch_nmi_watchdog
- Fix bug that caused incorrect performance counters to be programmed in a
few cases on K8.
- Remove useless check for local APIC
- Use local_t and per_cpu variables for per CPU data.
- Keep other CPUs busy during check_nmi_watchdog to make sure they really
tick when in lapic mode.
- Only check CPUs that are actually online.
- Various other fixes.
- Fix fallback path when MSRs are unimplemented
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Originally from Matt Tolentino
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Use bitmap_zero instead of bitmap_empty to initialise cpu mask This makes it
actually run reliable instead of relying on stack state.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The PTEs can point to ioremap mappings too, and these are often outside
mem_map. The NUMA hash page lookup functions cannot handle out of bounds
accesses properly.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Allowed user programs to set a non canonical segment base, which would cause
oopses in the kernel later.
Credit-to: Alexander Nyberg <alexn@dsv.su.se>
For identifying and reporting this bug.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This works around an AMD Erratum.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
There are unfortunately more and more multi processor Opteron systems which
don't have HPET timer support in the southbridge. This covers in particular
Nvidia and VIA chipsets. They also don't guarantee that the TSCs are
synchronized between CPUs; and especially with MP powernow the systems are
nearly unusable because the time gets very inconsistent between CPUs.
The timer code for x86-64 was originally written under the assumption that we
could fall back to the HPET timer on such systems. But this doesn't work
there.
Another alternative is to use the ACPI PM timer as primary time source. This
patch does that. The kernel only uses PM timer when there is no other choice
because it has some disadvantages.
Ported over from i386. It should be faster than the i386 version because I
dropped the "read three times" workaround, but is still considerable slower
than HPET and also does not work together with vsyscalls which have to be
disabled.
Cc: <mark.langsdorf@amd.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
It is unnecessary on modern Intel or AMD systems, and that is all we support
on x86-64
Also causes problems on various systems
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
It is not very useful to the user and more an kernel internal implementation
detail. So hide it.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The new TSC sync algorithm recently submitted did not work too well.
The result was that some MP machines where the TSC came up of the BIOS very
unsynchronized and that did not have HPET support were nearly unusable because
the time would jump forwards and backwards between CPUs.
After a lot of research ;-) and some more prototypes I ended up with just
using the one from IA64 which looks best. It has some internal self tuning
that should adapt to changing interconnect latencies. It holds up in my tests
so far.
I believe it was originally written by David Mosberger, I just ported it over
to x86-64. See the inline comment for a description.
This cleans up the code because it uses smp_call_function for syncing instead
of having custom hooks in SMP bootup.
Please note that the cycle numbers it outputs are too optimistic because they
do not take into account the latency of WRMSR and RDTSC, which can be hundreds
of cycles. It seems to be able to sync a dual Opteron to 200-300 cycles,
which is probably good enough.
There is a timing window during AP bootup where interrupts can see
inconsistent time before the TSC is synced. It is hard to avoid unfortunately
because we can only do the TSC sync after some setup, and we need to enable
interrupts before that. I just ignored it for now.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
It could be in a memory hole not mapped in mem_map and that causes the hash
lookup to go off to nirvana.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Last round hopefully of cpu_core_id changes hopefully fow now:
- Always initialize cpu_core_id for all CPUs, even when no dual core setup
is detected. This prevents funny /proc/cpuinfo output
- Do the same with phys_proc_id[] even when no HyperThreading - dito.
- Use the CPU APIC-ID from CPUID 1 instead of the linux virtual CPU number
to identify the core for AMD dual core setups.
Patch for i386/x86-64.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Cleans up the system exit call slightly and synchronizes with my tree again.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
NR_CPUs can be quite big these days. kmalloc the per CPU array instead of
putting it onto the stack
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
When I do a "diff -Nur arch/i386 arch/x86_64" to see what is different between these two
architectures, I see some differences due to whitespace issues only. The attached patch removes
some of the noise by fixing up the following files:
- arch/i386/boot/bootsect.S
- arch/i386/boot/video.S
- arch/x86_64/boot/bootsect.S
Signed-off-by: Daniel Dickman <didickman@yahoo.com>
Signed-off-by: Domen Puncer <domen@coderock.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Kprobes could not handle the insertion of a probe on the ret/lret
instruction and used to oops after single stepping since kprobes was
modifying eip/rip incorrectly. Adjustment of eip/rip is not required after
single stepping in case of ret/lret instruction, because eip/rip points to
the correct location after execution of the ret/lret instruction. This
patch fixes the above problem.
Signed-off-by: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
In include/asm-x86_64/string.h there are such comments:
/* Use C out of line version for memcmp */
#define memcmp __builtin_memcmp
int memcmp(const void * cs,const void * ct,size_t count);
This would mean that if the compiler does not decide to use __builtin_memcmp,
it emits a call to memcmp to be satisfied by the C out-of-line version in
lib/string.c. What happens is that after preprocessing, in lib/string.i you
may find the definition of "__builtin_strcmp".
Actually, by accident, in the object you will find the definition of strcmp
and such (maybe a trick intended to redirect calls to __builtin_memcmp to the
default memcmp when the definition is not expanded); however, this particular
case is not a documented feature as far as I can see.
Also, the EXPORT_SYMBOL does not work, so it's duplicated in the arch.
I simply added some #undef to lib/string.c and removed the (now duplicated)
exports in x86-64 and UML/x86_64 subarchs (the second ones are introduced by
another patch I just posted for -mm).
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
CC: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
These are some trivial fixes for the x86-64 subarch module support. The only
potential problem is that I have to modify arch/x86_64/kernel/module.c, to
avoid copying the whole of it.
I can't use it verbatim because it depends on a special vmalloc-like area for
modules, which for now (maybe that's to fix, I guess not) UML/x86-64 has not.
I went the easy way and reused the i386 vmalloc()-based allocator.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Acked-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
A bunch of drivers use ISA DMA helpers or their equivalents for
platforms that have ISA with different DMA controller (a lot of ARM
boxen). Currently there is no way to put such dependency in Kconfig -
CONFIG_ISA is not it (e.g. it is not set on platforms that have no ISA
slots, but have on-board devices that pretend to be ISA ones).
New symbol added - ISA_DMA_API. Set when we have functional
enable_dma()/set_dma_mode()/etc. set of helpers. Next patches in the
series will add missing dependencies for drivers that need them.
I'm very carefully staying the hell out of the recurring flamefest on
what exactly CONFIG_ISA would mean in ideal world - added symbol has a
well-defined meaning and for now I really want to treat it as completely
independent from the mess around CONFIG_ISA.
Signed-off-by: Al Viro <viro@parcelfarce.linux.theplanet.co.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Another large rollup of various patches from Adrian which make things static
where they were needlessly exported.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Convert most of the current code that uses _NSIG directly to instead use
valid_signal(). This avoids gcc -W warnings and off-by-one errors.
Signed-off-by: Jesper Juhl <juhl-lkml@dif.dk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This strcpy can run off the end of saved_command_line, and we don't need it any more anyway.
Signed-off-by: Alexander Nyberg <alexn@telia.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Brings sanitize_e820_map() in x86-64 in sync with that of i386.
x86_64 version was missing the changes from this patch.
http://linux.bkbits.net:8080/linux-2.6/cset@3e5e4083Y3HevldZl5KCy94V4DcZww?nav=index.html|src/|src/arch|src/arch/i386|src/arch/i386/kernel|related/arch/i386/kernel/setup.c
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Acked-by: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The specifications that talk about E820 map doesn't have an upper limit on
the number of e820 entries. But, today's kernel has a hard limit of 32.
With increase in memory size, we are seeing the number of E820 entries
reaching close to 32. Patch below bumps the number upto 128.
The patch changes the location of EDDBUF in zero-page (as it comes after E820).
As, EDDBUF is not used by boot loaders, this patch should not have any effect
on bootloader-setup code interface.
Patch covers both i386 and x86-64.
Tested on:
* grub booting bzImage
* lilo booting bzImage with EDID info enabled
* pxeboot of bzImage
Side-effect:
bss increases by ~ 2K and init.data increases by ~7.5K
on all systems, due to increase in size of static arrays.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
http://bugme.osdl.org/show_bug.cgi?id=4426
vendor_id : AuthenticAMD
cpu family : 6
model : 10
model name : AMD Athlon(tm) XP
stepping : 0
cpu MHz : 2204.807
<snipped>
cpuid level : 1
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov
pat pse36 mmx fxsr sse pni syscall mmxext 3dnowext 3dnow
bogomips : 4358.14
We're marking bit 0 of extended function 0x80000001 cpuid as PNI support on
AMD processors, when it actually denotes x87 FPU present. Patch for i386
and x86_64 below.
Signed-off-by: Zwane Mwaikambo <zwane@arm.linux.org.uk>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The recent support for K8 multicore was misported from x86-64 to i386, due
to an unnecessary inconsistency between the CPUID code. Sure, there is are
no x86-64 VIA chips yet, but it should happen eventually.
This patch fixes the i386 bug as well as makes x86-64 match i386 in the
handing of the CPUID array.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
A bug against an xSeries system showed up recently noting that the
check_nmi_watchdog() test was failing.
I have been investigating it and discovered in both i386 and x86_64 the
recent change to the routine to use the cpu_callin_map has uncovered a
problem. Prior to that change, on an SMP box, the test was trivally
passing because all cpu's were found to not yet be online, but now with the
callin_map they are discovered, it goes on to test the counter and they
have not yet begun to increment, so it announces a CPU is stuck and bails
out.
On all the systems I have access to test, the announcement of failure is
also bougs... by the time you can login and check /proc/interrupts, the
NMI count is happily incrementing on all CPUs. Its just that the test is
being done too early.
I have tried moving the call to the test around a bit, and it was always
too early. I finally hit on this proposed solution, it delays the routine
via a late_initcall(), seems like the right solution to me.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The new i386/x86_64 assemblers no longer accept instructions for moving
between a segment register and a 32bit memory location, i.e.,
movl (%eax),%ds
movl %ds,(%eax)
To generate instructions for moving between a segment register and a
16bit memory location without the 16bit operand size prefix, 0x66,
mov (%eax),%ds
mov %ds,(%eax)
should be used. It will work with both new and old assemblers. The
assembler starting from 2.16.90.0.1 will also support
movw (%eax),%ds
movw %ds,(%eax)
without the 0x66 prefix. I am enclosing patches for 2.4 and 2.6 kernels
here. The resulting kernel binaries should be unchanged as before, with
old and new assemblers, if gcc never generates memory access for
unsigned gsindex;
asm volatile("movl %%gs,%0" : "=g" (gsindex));
If gcc does generate memory access for the code above, the upper bits
in gsindex are undefined and the new assembler doesn't allow it.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
We were calling ptrace_notify() after auditing the syscall and arguments,
but the debugger could have _changed_ them before the syscall was actually
invoked. Reorder the calls to fix that.
While we're touching ever call to audit_syscall_entry(), we also make it
take an extra argument: the architecture of the syscall which was made,
because some architectures allow more than one type of syscall.
Also add an explicit success/failure flag to audit_syscall_exit(), for
the benefit of architectures which return that in a condition register
rather than only returning a single register.
Change type of syscall return value to 'long' not 'int'.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
The addition of the PT_NOTE didn't take in the x86_64 version of the i386
vDSO, because I forgot the linker script bit in that copy.
Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
->pretcode in struct rt_sigframe is a userland pointer (and already
treated as such by code using that field).
Signed-off-by: Al Viro <viro@parcelfarce.linux.theplanet.co.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The labels after the last put_user patch were misplaced so
exceptions on the real mov instructions would not be handled.
Noted by Brian Gerst <bgerst@didntduck.org>
The new out of line put_user() assembly on x86_64 changes %rcx without
telling GCC about it causing things like:
http://bugme.osdl.org/show_bug.cgi?id=4515
See to it that %rcx is not changed (made it consistent with get_user()).
Signed-off-by: Alexander Nyberg <alexn@telia.com>
Signed-off-by: ak@suse.de
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
I thought I'm done with fixing u32 vs. pm_message_t ... unfortunately that
turned out not to be the case... Here are fixes x86-64.
Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
- broken sibling_map setup in x86_64
- grouping all the core and HT related cpuinfo fields.
We are reasonably sure that adding new cpuinfo fields after "siblings" field,
will not cause any app failure. Thats because today's /proc/cpuinfo
format is completely different on x86, x86_64 and we haven't heard of any
x86 app breakage because of this issue. Grouping these fields will
result in more or less common format on all architectures (ia64, x86 and
x86_64) and will cause less confusion.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This will allow hotplug CPU in the future and in general cleans up a lot of
crufty code. It also should plug some races that the old hackish way
introduces. Remove one old race workaround in NMI watchdog setup that is not
needed anymore.
I removed the old total sum of bogomips reporting code. The brag value of
BogoMips has been greatly devalued in the last years on the open market.
Real CPU hotplug will need some more work, but the infrastructure for it is
there now.
One drawback: the new TSC sync algorithm is less accurate than before. The
old way of zeroing TSCs is too intrusive to do later. Instead the TSC of the
BP is duplicated now, which is less accurate.
akpm:
- sync_tsc_bp_init seems to have the sense of `init' inverted.
- SPIN_LOCK_UNLOCKED is deprecated - use DEFINE_SPINLOCK.
Cc: <rusty@rustcorp.com.au>
Cc: <mingo@elte.hu>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
It was confusingly named.
Signed-off-by: Andi Kleen <ak@suse.de>
DESC
x86_64: Switch SMP bootup over to new CPU hotplug state machine
EDESC
From: "Andi Kleen" <ak@suse.de>
This will allow hotplug CPU in the future and in general cleans up a lot of
crufty code. It also should plug some races that the old hackish way
introduces. Remove one old race workaround in NMI watchdog setup that is not
needed anymore.
I removed the old total sum of bogomips reporting code. The brag value of
BogoMips has been greatly devalued in the last years on the open market.
Real CPU hotplug will need some more work, but the infrastructure for it is
there now.
One drawback: the new TSC sync algorithm is less accurate than before. The
old way of zeroing TSCs is too intrusive to do later. Instead the TSC of the
BP is duplicated now, which is less accurate.
Cc: <rusty@rustcorp.com.au>
Cc: <mingo@elte.hu>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Exceptions and hardware interrupts can, to a certain degree, nest, so when
attempting to follow the sequence of stacks used in order to dump their
contents this has to be accounted for. Also, IST stacks have their tops
stored in the TSS, so there's no need to add the stack size to get to their
ends.
Minor changes from AK.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Clean up the code greatly. Now uses the infrastructure from the Intel dual
core patch Should fix a final bug noticed by Tyan of not detecting the nodes
correctly in some corner cases.
Patch for x86-64 and i386
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Appended patch adds the support for Intel dual-core detection and displaying
the core related information in /proc/cpuinfo.
It adds two new fields "core id" and "cpu cores" to x86 /proc/cpuinfo and the
"core id" field for x86_64("cpu cores" field is already present in x86_64).
Number of processor cores in a die is detected using cpuid(4) and this is
documented in IA-32 Intel Architecture Software Developer's Manual (vol 2a)
(http://developer.intel.com/design/pentium4/manuals/index_new.htm#sdm_vol2a)
This patch also adds cpu_core_map similar to cpu_sibling_map.
Slightly hacked by AK.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Calling a notifier three times in the debug handler does not make much sense,
because a debugger can figure out the various conditions by itself. Remove
the additional calls to DIE_DEBUG and DIE_DEBUGSTEP completely.
This matches what i386 does now.
This also makes sure interrupts are always still disabled when calling a
debugger, which prevents:
BUG: using smp_processor_id() in preemptible [00000001] code: tpopf/1470
caller is post_kprobe_handler+0x9/0x70
Call Trace:<ffffffff8024f10f>{smp_processor_id+191} <ffffffff80120e69>{post_kpro
be_handler+9}
<ffffffff80120f7a>{kprobe_exceptions_notify+58}
<ffffffff80144fc0>{notifier_call_chain+32} <ffffffff80110daf>{do_debug+335}
<ffffffff8010f513>{debug+127} <EOE>
on preemptible debug kernels with kprobes when single stepping in user space.
This was probably a bug even on non preempt kernels, this function was
supposed to be running with interrupts off according to a comment there.
Note to third part debugger maintainers: please double check your debugger can
still single step.
Cc: <prasanna@in.ibm.com>
Cc: <jbeulich@novell.com>
Cc: <kaos@sgi.com>
Cc: <jim.houston@ccur.com>
Cc: <jfv@bluesong.net>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
