We found a problem with x86_64 kernels with preemption enabled, where
having multiple tasks doing ptrace singlesteps around the same time will
cause the system to 'oops'. The problem seems that a task can get
preempted out of the do_debug() processing while it is running on the
DEBUG_STACK stack. If another task on that same cpu then enters do_debug()
and uses the same per-cpu DEBUG_STACK stack, the previous preempted tasks's
stack contents can be corrupted, and the system will oops when the
preempted task is context switched back in again.
The typical oops looks like the following:
Unable to handle kernel paging request at ffffffffffffffae RIP: <ffffffff805452a1>{thread_return+34}
PGD 103027 PUD 102429067 PMD 0
Oops: 0002 [1] PREEMPT SMP
CPU 0
Modules linked in:
Pid: 3786, comm: ssdd Not tainted 2.6.15.2 #1
RIP: 0010:[<ffffffff805452a1>] <ffffffff805452a1>{thread_return+34}
RSP: 0018:ffffffff80824058 EFLAGS: 000136c2
RAX: ffff81017e12cea0 RBX: 0000000000000000 RCX: 00000000c0000100
RDX: 0000000000000000 RSI: ffff8100f7856e20 RDI: ffff81017e12cea0
RBP: 0000000000000046 R08: ffff8100f68a6000 R09: 0000000000000000
R10: 0000000000000000 R11: ffff81017e12cea0 R12: ffff81000c2d53e8
R13: ffff81017f5b3be8 R14: ffff81000c0036e0 R15: 000001056cbfc899
FS: 00002aaaaaad9b00(0000) GS:ffffffff80883800(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: ffffffffffffffae CR3: 00000000f6fcf000 CR4: 00000000000006e0
Process ssdd (pid: 3786, threadinfo ffff8100f68a6000, task ffff8100f7856e20)
Stack: ffffffff808240d8 ffffffff8012a84a ffff8100055f6c00 0000000000000020
0000000000000001 ffff81000c0036e0 ffffffff808240b8 0000000000000000
0000000000000000 0000000000000000
Call Trace: <#DB>
<ffffffff8012a84a>{try_to_wake_up+985}
<ffffffff8012c0d3>{kick_process+87}
<ffffffff8013b262>{signal_wake_up+48}
<ffffffff8013b5ce>{specific_send_sig_info+179}
<ffffffff80546abc>{_spin_unlock_irqrestore+27}
<ffffffff8013b67c>{force_sig_info+159}
<ffffffff801103a0>{do_debug+289} <ffffffff80110278>{sync_regs+103}
<ffffffff8010ed9a>{paranoid_userspace+35}
Unable to handle kernel paging request at 00007fffffb7d000 RIP: <ffffffff8010f2e4>{show_trace+465}
PGD f6f25067 PUD f6fcc067 PMD f6957067 PTE 0
Oops: 0000 [2] PREEMPT SMP
This patch disables preemptions for the task upon entry to do_debug(), before
interrupts are reenabled, and then disables preemption before exiting
do_debug(), after disabling interrupts. I've noticed that the task can be
preempted either at the end of an interrupt, or on the call to
force_sig_info() on the spin_unlock_irqrestore() processing. It might be
better to attempt to code a fix in entry.S around the code that calls
do_debug().
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
[description from AK]
The IBM Summit 3 chipset doesn't implement the HPET timer replacement
option. Since the current Linux code relies on it use a mixed mode with
both PIT for the interrupt and HPET counters for the time keeping. That
was already implemented, but didn't work properly because it was still
using the last interrupt offset in HPET. This resulted in x460 not
booting. Fix this up by using the free running HPET counter.
Shouldn't affect any other machine because they either use full HPET mode
or no HPET at all.
TBD needs a similar 32bit fix.
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>
Cc: Bob Picco <bob.picco@hp.com>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The *at patches introduced fstatat and, due to inusfficient research, I
used the newfstat functions generally as the guideline. The result is that
on 32-bit platforms we don't have all the information needed to implement
fstatat64.
This patch modifies the code to pass up 64-bit information if
__ARCH_WANT_STAT64 is defined. I renamed the syscall entry point to make
this clear. Other archs will continue to use the existing code. On x86-64
the compat code is implemented using a new sys32_ function. this is what
is done for the other stat syscalls as well.
This patch might break some other archs (those which define
__ARCH_WANT_STAT64 and which already wired up the syscall). Yet others
might need changes to accomodate the compatibility mode. I really don't
want to do that work because all this stat handling is a mess (more so in
glibc, but the kernel is also affected). It should be done by the arch
maintainers. I'll provide some stand-alone test shortly. Those who are
eager could compile glibc and run 'make check' (no installation needed).
The patch below has been tested on x86 and x86-64.
Signed-off-by: Ulrich Drepper <drepper@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Currently, x86_64 and ia64 arches do not clear the corresponding bits in
the node's cpumask when a cpu goes down or cpu bring up is cancelled. This
is buggy since there are pieces of common code where the cpumask is checked
in the cpu down code path to decide on things (like in the slab down path).
PPC does the right thing, but x86_64 and ia64 don't (This was the reason
Sonny hit upon a slab bug during cpu offline on ppc and could not reproduce
on other arches). This patch fixes it for x86_64. I won't attempt ia64 as
I cannot test it.
Credit for spotting this should go to Alok.
(akpm: this was applied, then reverted. But it's OK now because we now use
for_each_cpu() in the right places).
Signed-off-by: Alok N Kataria <alokk@calsoftinc.com>
Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Shai Fultheim <shai@scalex86.org>
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 reverts commit 10f4dc8b27.
Quoth Andi Kleen:
"Kiran decided that it makes the problem worse than it was before.
Fixing it fully requires more work which is too much for 2.6.16. So
please revert that commit for now."
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch contains a printk reorder to remove the current problem of
displaying "PCI-DMA: Disabling IOMMU." and then "PCI-DMA: using GART
IOMMU" 20 lines later in dmesg.
It also constains a printk reorder in swiotlb to state swiotlb
enablement prior to describing the location of the bounce buffers, and a
printk reorder to state gart enablement prior to describing the
aperature.
Also constains a whitespace cleanup in arch/x86_64/kernel/setup.c
Tested (along with patch 2/2) on dual opteron with gart enabled,
iommu=soft, and iommu=off.
Signed-off-by: Jon Mason <jdmason@us.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Hack for 2.6.16. In 2.6.17 all code that uses NR_CPUs should
be audited and changed to only touch possible CPUs.
Don't mark the reference per cpu data init data (so it stays
around after boot) and point all impossible CPUs to it. This way
they reference some valid - although shared memory. Usually
this is only initialization like INIT_LIST_HEADs and there
won't be races because these CPUs never run. Still somewhat hackish.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
It's bad juju to touch the APIC when it hasn't been enabled.
I also moved ack_bad_irq for x86-64 out of line following i386.
Signed-off-by: Andi Kleen <ak@suse.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Checking of the validity of pointers should be consistently done before
dereferencing the pointer.
Signed-Off-By: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Conditionalize two unwind directives to match other similarly
conditional code.
Signed-Off-By: Jan Beulich <jbeulich@novell.com>
Cc: Jim Houston <jim.houston@ccur.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
On some broken motherboards (at least one NForce3 based AMD64 laptop)
the PIT timer runs at a incorrect frequency. This patch adds a new
option "apicpmtimer" that allows to use the APIC timer and calibrate it
using the PMTimer. It requires the earlier patch that allows to run the
main timer from the APIC.
Specifying apicpmtimer implies apicmaintimer.
The option defaults to off for now.
I tested it on a few systems and the resulting APIC timer frequencies
were usually a bit off, but always <1%, which should be tolerable.
TBD figure out heuristic to enable this automatically on the affected
systems TBD perhaps do it on all NForce3s or using DMI?
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
kprobes cannot deal with the funny calling conventions when it
runs on a different stack when it returns. If someone wants
to instrument context switch they can add a probe to schedule()
instead.
Cc: jkenisto@us.ibm.com, prasanna@in.ibm.com
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Align the start of the per-cpu section to the configured number of bytes in a
cache line. This stops a BUG_ON() from triggering in load_module() when
DEFINE_PER_CPU() is used in a module and the section isn't cacheline-aligned.
Rusty also found this and sent a patch in a while ago
(http://lkml.org/lkml/2004/10/19/17), I don't know what came of that.
Signed-off-by: Zach Brown <zach.brown@oracle.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
[ AK: I redid Kevin's fix to be simpler, but the idea and original
analysis of the problem is from Kevin]
This avoid allocation failures on some SATA systems like Nvidia CK8
when the IOMMU gets fragmented. Modern SATA devices have quite large queues
(128 entries) and the FS with ext2/3 is good enough now that it often
passes whole 128 page sg lists down to the driver. These require
512K of continuous free space in the IOMMU aperture to map when merged.
When the IOMMU is fragmented this could lead to spurious IO errors
due to failing mappings.
Short term fix is to just try to map the SG list again unmerged
page by page - this way fragmentation doesn't matter anymore.
The code for that was already there, but it just wasn't enabled for the
merge case.
According to Kevin at least the Nvidia device doesn't seem to benefit
from merging much anyways, so the only slowdown is from trying
to do an unnecessary merge attempt.
Kevin plans to implement better fragmentation avoidance in the future,
but that wouldn't be 2.6.16 material.
TBD: should add some statistic counters to count how often that really
happens.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
I broke this earlier when moving the patch from i386 to x86-64.
Need to return the virtual address here, not the physical address.
This fixes some boot time crashes on x86-64.
Cc: gregkh@suse.de
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
- Check if the processor/memory affinity entries are long enough
according to the ACPI 3.0 spec.
- Ignore memory affinity entries that define a zero length region.
All based on BIOS issues found in the field @)
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
attached patch is 2 more cases i found via running the reference_init.pl
script. These were easy to spot just knowing the file names. There is
one another about init/main.c that i cant exactly zero in. (partly
because i dont know how to interpret the data thats spewed out of the tool).
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
It has been enabled by default for some time now and is cheap enough
so it doesn't matter anyways.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Currently, x86_64 and ia64 arches do not clear the corresponding bits
in the node's cpumask when a cpu goes down or cpu bring up is cancelled.
This is buggy since there are pieces of common code where the cpumask is
checked in the cpu down code path to decide on things (like in the slab
down path). PPC does the right thing, but x86_64 and ia64 don't (This
was the reason Sonny hit upon a slab bug during cpu offline on ppc and
could not reproduce on other arches). This patch fixes it for x86_64.
I won't attempt ia64 as I cannot test it.
Credit for spotting this should go to Alok.
Signed-off-by: Alok N Kataria <alokk@calsoftinc.com>
Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Shai Fultheim <shai@scalex86.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
They cause quite bad performance regressions on Netburst
This is temporary until we can get new optimized functions
for these CPUs.
This undoes changes that were done in 2.6.15 and in 2.6.16-rc1,
essentially bringing the code back to 2.6.14 level. Only change
is I renamed the X86_FEATURE_K8_C flag to X86_FEATURE_REP_GOOD
and fixed the check for the flag and also fixed some comments.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This avoids BUG_ONs in the low level allocator when an illegal
GFP mask is added.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
At resume time, TSC's value or something similar might be changed a lot
against suspend time. This could make system gets a very big lost ticks.
See http://bugzilla.kernel.org/show_bug.cgi?id=5825
Signed-off-by: Shaohua Li<shaohua.li@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
They all have problems with IRQ 0 routing, so just use the APIC on them.
Can be overwritten with "noapicmaintimer"
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Another piece from the no-idle-tick patch.
This can be enabled with the "apicmaintimer" option.
This is mainly useful when the PIT/HPET interrupt is unreliable.
Note there are some systems that are known to stop the APIC
timer in C3. For those it will never work, but this case
should be automatically detected.
It also only works with PM timer right now. When HPET is used
the way the main timer handler computes the delay doesn't work.
It should be a bit more efficient because there is one less
regular interrupt to process on the boot processor.
Requires earlier bugfix from Venkatesh
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
A kprobe executes IRET early and that could cause NMI recursion
and stack corruption.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This assembly version is measurably faster than the generic version in
lib/iomap_copy.c.
Signed-off-by: Bryan O'Sullivan <bos@pathscale.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
We need to use the compat function here.
Pointer out by Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Handle more bogus MCFG entries
Some Asus P4 boards seem to have broken MCFG tables with
only a single entry for busses 0-0. Special case these
and assume they mean all busses can be accessed.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Fix a typo/mis-merge in one of the previous patches.
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>
Adds the ability to disability packet split at compile time and use the legacy receive path on PCI express hardware. Made this a CONFIG option and modified the Kconfig, to reflect the new option.
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: John Ronciak <john.ronciak@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
Add x86-64 specific memory hot-add functions, Kconfig options,
and runtime kernel page table update functions to make
hot-add usable on x86-64 machines. Also, fixup the nefarious
conditional locking and exports pointed out by Andi.
Tested on Intel and IBM x86-64 memory hot-add capable systems.
Signed-off-by: Matt Tolentino <matthew.e.tolentino@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Another try at this.
For 32bit follow the 32bit implementation from Ingo -
mappings are growing down from the end of stack now
and vary randomly by 1GB.
Randomized mappings for 64bit just vary the normal mmap break
by 1TB. I didn't bother implementing full flex mmap for 64bit
because it shouldn't be needed there.
Cc: mingo@elte.hu
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
... as they are no longer needed. Since there were hard-coded numbers in the
file, the patch also adds a mechanism to avoid these (otherwise potential
future changes would again and again require adjusting these numbers).
Signed-Off-By: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The comparison of the initrd start address against "&_end" is
unnecessary and incorrect. Make it match the x86 code that just
compares the passed-in arguments.
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
For not fully explained reasons it broke mem=... on several setups.
Also minor cleanup.
Cc: axboe@suse.de
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
To avoid mistakes.
I got a few reports where people got broken timing because they didn't
have the PMTIMER fallback.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
