Pull five Xen bug-fixes from Konrad Rzeszutek Wilk:
- When booting as PVHVM we would try to use PV console - but would not validate
the parameters causing us to crash during restore b/c we re-use the wrong event
channel.
- When booting on machines with SR-IOV PCI bridge we didn't check for the bridge
and tried to use it.
- Under AMD machines would advertise the APERFMPERF resulting in needless amount
of MSRs from the guest.
- A global value (xen_released_pages) was not subtracted at bootup when pages
were added back in. This resulted in the balloon worker having the wrong
account of how many pages were truly released.
- Fix dead-lock when xen-blkfront is run in the same domain as xen-blkback.
* tag 'stable/for-linus-3.5-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
xen: mark local pages as FOREIGN in the m2p_override
xen/setup: filter APERFMPERF cpuid feature out
xen/balloon: Subtract from xen_released_pages the count that is populated.
xen/pci: Check for PCI bridge before using it.
xen/events: Add WARN_ON when quick lookup found invalid type.
xen/hvc: Check HVM_PARAM_CONSOLE_[EVTCHN|PFN] for correctness.
xen/hvc: Fix error cases around HVM_PARAM_CONSOLE_PFN
xen/hvc: Collapse error logic.
When the frontend and the backend reside on the same domain, even if we
add pages to the m2p_override, these pages will never be returned by
mfn_to_pfn because the check "get_phys_to_machine(pfn) != mfn" will
always fail, so the pfn of the frontend will be returned instead
(resulting in a deadlock because the frontend pages are already locked).
INFO: task qemu-system-i38:1085 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
qemu-system-i38 D ffff8800cfc137c0 0 1085 1 0x00000000
ffff8800c47ed898 0000000000000282 ffff8800be4596b0 00000000000137c0
ffff8800c47edfd8 ffff8800c47ec010 00000000000137c0 00000000000137c0
ffff8800c47edfd8 00000000000137c0 ffffffff82213020 ffff8800be4596b0
Call Trace:
[<ffffffff81101ee0>] ? __lock_page+0x70/0x70
[<ffffffff81a0fdd9>] schedule+0x29/0x70
[<ffffffff81a0fe80>] io_schedule+0x60/0x80
[<ffffffff81101eee>] sleep_on_page+0xe/0x20
[<ffffffff81a0e1ca>] __wait_on_bit_lock+0x5a/0xc0
[<ffffffff81101ed7>] __lock_page+0x67/0x70
[<ffffffff8106f750>] ? autoremove_wake_function+0x40/0x40
[<ffffffff811867e6>] ? bio_add_page+0x36/0x40
[<ffffffff8110b692>] set_page_dirty_lock+0x52/0x60
[<ffffffff81186021>] bio_set_pages_dirty+0x51/0x70
[<ffffffff8118c6b4>] do_blockdev_direct_IO+0xb24/0xeb0
[<ffffffff811e71a0>] ? ext3_get_blocks_handle+0xe00/0xe00
[<ffffffff8118ca95>] __blockdev_direct_IO+0x55/0x60
[<ffffffff811e71a0>] ? ext3_get_blocks_handle+0xe00/0xe00
[<ffffffff811e91c8>] ext3_direct_IO+0xf8/0x390
[<ffffffff811e71a0>] ? ext3_get_blocks_handle+0xe00/0xe00
[<ffffffff81004b60>] ? xen_mc_flush+0xb0/0x1b0
[<ffffffff81104027>] generic_file_aio_read+0x737/0x780
[<ffffffff813bedeb>] ? gnttab_map_refs+0x15b/0x1e0
[<ffffffff811038f0>] ? find_get_pages+0x150/0x150
[<ffffffff8119736c>] aio_rw_vect_retry+0x7c/0x1d0
[<ffffffff811972f0>] ? lookup_ioctx+0x90/0x90
[<ffffffff81198856>] aio_run_iocb+0x66/0x1a0
[<ffffffff811998b8>] do_io_submit+0x708/0xb90
[<ffffffff81199d50>] sys_io_submit+0x10/0x20
[<ffffffff81a18d69>] system_call_fastpath+0x16/0x1b
The explanation is in the comment within the code:
We need to do this because the pages shared by the frontend
(xen-blkfront) can be already locked (lock_page, called by
do_read_cache_page); when the userspace backend tries to use them
with direct_IO, mfn_to_pfn returns the pfn of the frontend, so
do_blockdev_direct_IO is going to try to lock the same pages
again resulting in a deadlock.
A simplified call graph looks like this:
pygrub QEMU
-----------------------------------------------
do_read_cache_page io_submit
| |
lock_page ext3_direct_IO
|
bio_add_page
|
lock_page
Internally the xen-blkback uses m2p_add_override to swizzle (temporarily)
a 'struct page' to have a different MFN (so that it can point to another
guest). It also can easily find out whether another pfn corresponding
to the mfn exists in the m2p, and can set the FOREIGN bit
in the p2m, making sure that mfn_to_pfn returns the pfn of the backend.
This allows the backend to perform direct_IO on these pages, but as a
side effect prevents the frontend from using get_user_pages_fast on
them while they are being shared with the backend.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Xen PV kernels allow access to the APERF/MPERF registers to read the
effective frequency. Access to the MSRs is however redirected to the
currently scheduled physical CPU, making consecutive read and
compares unreliable. In addition each rdmsr traps into the hypervisor.
So to avoid bogus readouts and expensive traps, disable the kernel
internal feature flag for APERF/MPERF if running under Xen.
This will
a) remove the aperfmperf flag from /proc/cpuinfo
b) not mislead the power scheduler (arch/x86/kernel/cpu/sched.c) to
use the feature to improve scheduling (by default disabled)
c) not mislead the cpufreq driver to use the MSRs
This does not cover userland programs which access the MSRs via the
device file interface, but this will be addressed separately.
Signed-off-by: Andre Przywara <andre.przywara@amd.com>
Cc: stable@vger.kernel.org # v3.0+
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
We did not take into account that xen_released_pages would be
used outside the initial E820 parsing code. As such we would
did not subtract from xen_released_pages the count of pages
that we had populated back (instead we just did a simple
extra_pages = released - populated).
The balloon driver uses xen_released_pages to set the initial
current_pages count. If this is wrong (too low) then when a new
(higher) target is set, the balloon driver will request too many pages
from Xen."
This fixes errors such as:
(XEN) memory.c:133:d0 Could not allocate order=0 extent: id=0 memflags=0 (51 of 512)
during bootup and
free_memory : 0
where the free_memory should be 128.
Acked-by: David Vrabel <david.vrabel@citrix.com>
[v1: Per David's review made the git commit better]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Pull Xen updates from Konrad Rzeszutek Wilk:
"Features:
* Extend the APIC ops implementation and add IRQ_WORKER vector
support so that 'perf' can work properly.
* Fix self-ballooning code, and balloon logic when booting as initial
domain.
* Move array printing code to generic debugfs
* Support XenBus domains.
* Lazily free grants when a domain is dead/non-existent.
* In M2P code use batching calls
Bug-fixes:
* Fix NULL dereference in allocation failure path (hvc_xen)
* Fix unbinding of IRQ_WORKER vector during vCPU hot-unplug
* Fix HVM guest resume - we would leak an PIRQ value instead of
reusing the existing one."
Fix up add-add onflicts in arch/x86/xen/enlighten.c due to addition of
apic ipi interface next to the new apic_id functions.
* tag 'stable/for-linus-3.5-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
xen: do not map the same GSI twice in PVHVM guests.
hvc_xen: NULL dereference on allocation failure
xen: Add selfballoning memory reservation tunable.
xenbus: Add support for xenbus backend in stub domain
xen/smp: unbind irqworkX when unplugging vCPUs.
xen: enter/exit lazy_mmu_mode around m2p_override calls
xen/acpi/sleep: Enable ACPI sleep via the __acpi_os_prepare_sleep
xen: implement IRQ_WORK_VECTOR handler
xen: implement apic ipi interface
xen/setup: update VA mapping when releasing memory during setup
xen/setup: Combine the two hypercall functions - since they are quite similar.
xen/setup: Populate freed MFNs from non-RAM E820 entries and gaps to E820 RAM
xen/setup: Only print "Freeing XXX-YYY pfn range: Z pages freed" if Z > 0
xen/gnttab: add deferred freeing logic
debugfs: Add support to print u32 array in debugfs
xen/p2m: An early bootup variant of set_phys_to_machine
xen/p2m: Collapse early_alloc_p2m_middle redundant checks.
xen/p2m: Allow alloc_p2m_middle to call reserve_brk depending on argument
xen/p2m: Move code around to allow for better re-usage.
Pull exception table generation updates from Ingo Molnar:
"The biggest change here is to allow the build-time sorting of the
exception table, to speed up booting. This is achieved by the
architecture enabling BUILDTIME_EXTABLE_SORT. This option is enabled
for x86 and MIPS currently.
On x86 a number of fixes and changes were needed to allow build-time
sorting of the exception table, in particular a relocation invariant
exception table format was needed. This required the abstracting out
of exception table protocol and the removal of 20 years of accumulated
assumptions about the x86 exception table format.
While at it, this tree also cleans up various other aspects of
exception handling, such as early(er) exception handling for
rdmsr_safe() et al.
All in one, as the result of these changes the x86 exception code is
now pretty nice and modern. As an added bonus any regressions in this
code will be early and violent crashes, so if you see any of those,
you'll know whom to blame!"
Fix up trivial conflicts in arch/{mips,x86}/Kconfig files due to nearby
modifications of other core architecture options.
* 'x86-extable-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (35 commits)
Revert "x86, extable: Disable presorted exception table for now"
scripts/sortextable: Handle relative entries, and other cleanups
x86, extable: Switch to relative exception table entries
x86, extable: Disable presorted exception table for now
x86, extable: Add _ASM_EXTABLE_EX() macro
x86, extable: Remove open-coded exception table entries in arch/x86/ia32/ia32entry.S
x86, extable: Remove open-coded exception table entries in arch/x86/include/asm/xsave.h
x86, extable: Remove open-coded exception table entries in arch/x86/include/asm/kvm_host.h
x86, extable: Remove the now-unused __ASM_EX_SEC macros
x86, extable: Remove open-coded exception table entries in arch/x86/xen/xen-asm_32.S
x86, extable: Remove open-coded exception table entries in arch/x86/um/checksum_32.S
x86, extable: Remove open-coded exception table entries in arch/x86/lib/usercopy_32.c
x86, extable: Remove open-coded exception table entries in arch/x86/lib/putuser.S
x86, extable: Remove open-coded exception table entries in arch/x86/lib/getuser.S
x86, extable: Remove open-coded exception table entries in arch/x86/lib/csum-copy_64.S
x86, extable: Remove open-coded exception table entries in arch/x86/lib/copy_user_nocache_64.S
x86, extable: Remove open-coded exception table entries in arch/x86/lib/copy_user_64.S
x86, extable: Remove open-coded exception table entries in arch/x86/lib/checksum_32.S
x86, extable: Remove open-coded exception table entries in arch/x86/kernel/test_rodata.c
x86, extable: Remove open-coded exception table entries in arch/x86/kernel/entry_64.S
...
Pull x86/apic changes from Ingo Molnar:
"Most of the changes are about helping virtualized guest kernels
achieve better performance."
Fix up trivial conflicts with the iommu updates to arch/x86/kernel/apic/io_apic.c
* 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/apic: Implement EIO micro-optimization
x86/apic: Add apic->eoi_write() callback
x86/apic: Use symbolic APIC_EOI_ACK
x86/apic: Fix typo EIO_ACK -> EOI_ACK and document it
x86/xen/apic: Add missing #include <xen/xen.h>
x86/apic: Only compile local function if used with !CONFIG_GENERIC_PENDING_IRQ
x86/apic: Fix UP boot crash
x86: Conditionally update time when ack-ing pending irqs
xen/apic: implement io apic read with hypercall
Revert "xen/x86: Workaround 'x86/ioapic: Add register level checks to detect bogus io-apic entries'"
xen/x86: Implement x86_apic_ops
x86/apic: Replace io_apic_ops with x86_io_apic_ops.
Pull smp hotplug cleanups from Thomas Gleixner:
"This series is merily a cleanup of code copied around in arch/* and
not changing any of the real cpu hotplug horrors yet. I wish I'd had
something more substantial for 3.5, but I underestimated the lurking
horror..."
Fix up trivial conflicts in arch/{arm,sparc,x86}/Kconfig and
arch/sparc/include/asm/thread_info_32.h
* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (79 commits)
um: Remove leftover declaration of alloc_task_struct_node()
task_allocator: Use config switches instead of magic defines
sparc: Use common threadinfo allocator
score: Use common threadinfo allocator
sh-use-common-threadinfo-allocator
mn10300: Use common threadinfo allocator
powerpc: Use common threadinfo allocator
mips: Use common threadinfo allocator
hexagon: Use common threadinfo allocator
m32r: Use common threadinfo allocator
frv: Use common threadinfo allocator
cris: Use common threadinfo allocator
x86: Use common threadinfo allocator
c6x: Use common threadinfo allocator
fork: Provide kmemcache based thread_info allocator
tile: Use common threadinfo allocator
fork: Provide weak arch_release_[task_struct|thread_info] functions
fork: Move thread info gfp flags to header
fork: Remove the weak insanity
sh: Remove cpu_idle_wait()
...
* stable/autoballoon.v5.2:
xen/setup: update VA mapping when releasing memory during setup
xen/setup: Combine the two hypercall functions - since they are quite similar.
xen/setup: Populate freed MFNs from non-RAM E820 entries and gaps to E820 RAM
xen/setup: Only print "Freeing XXX-YYY pfn range: Z pages freed" if Z > 0
xen/p2m: An early bootup variant of set_phys_to_machine
xen/p2m: Collapse early_alloc_p2m_middle redundant checks.
xen/p2m: Allow alloc_p2m_middle to call reserve_brk depending on argument
xen/p2m: Move code around to allow for better re-usage.
Provide the registration callback to call in the Xen's
ACPI sleep functionality. This means that during S3/S5
we make a hypercall XENPF_enter_acpi_sleep with the
proper PM1A/PM1B registers.
Based of Ke Yu's <ke.yu@intel.com> initial idea.
[ From http://xenbits.xensource.com/linux-2.6.18-xen.hg
change c68699484a65 ]
[v1: Added Copyright and license]
[v2: Added check if PM1A/B the 16-bits MSB contain something. The spec
only uses 16-bits but might have more in future]
Signed-off-by: Liang Tang <liang.tang@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
In xen_memory_setup(), if a page that is being released has a VA
mapping this must also be updated. Otherwise, the page will be not
released completely -- it will still be referenced in Xen and won't be
freed util the mapping is removed and this prevents it from being
reallocated at a different PFN.
This was already being done for the ISA memory region in
xen_ident_map_ISA() but on many systems this was omitting a few pages
as many systems marked a few pages below the ISA memory region as
reserved in the e820 map.
This fixes errors such as:
(XEN) page_alloc.c:1148:d0 Over-allocation for domain 0: 2097153 > 2097152
(XEN) memory.c:133:d0 Could not allocate order=0 extent: id=0 memflags=0 (0 of 17)
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
They use the same set of arguments, so it is just the matter
of using the proper hypercall.
Acked-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
When the Xen hypervisor boots a PV kernel it hands it two pieces
of information: nr_pages and a made up E820 entry.
The nr_pages value defines the range from zero to nr_pages of PFNs
which have a valid Machine Frame Number (MFN) underneath it. The
E820 mirrors that (with the VGA hole):
BIOS-provided physical RAM map:
Xen: 0000000000000000 - 00000000000a0000 (usable)
Xen: 00000000000a0000 - 0000000000100000 (reserved)
Xen: 0000000000100000 - 0000000080800000 (usable)
The fun comes when a PV guest that is run with a machine E820 - that
can either be the initial domain or a PCI PV guest, where the E820
looks like the normal thing:
BIOS-provided physical RAM map:
Xen: 0000000000000000 - 000000000009e000 (usable)
Xen: 000000000009ec00 - 0000000000100000 (reserved)
Xen: 0000000000100000 - 0000000020000000 (usable)
Xen: 0000000020000000 - 0000000020200000 (reserved)
Xen: 0000000020200000 - 0000000040000000 (usable)
Xen: 0000000040000000 - 0000000040200000 (reserved)
Xen: 0000000040200000 - 00000000bad80000 (usable)
Xen: 00000000bad80000 - 00000000badc9000 (ACPI NVS)
..
With that overlaying the nr_pages directly on the E820 does not
work as there are gaps and non-RAM regions that won't be used
by the memory allocator. The 'xen_release_chunk' helps with that
by punching holes in the P2M (PFN to MFN lookup tree) for those
regions and tells us that:
Freeing 20000-20200 pfn range: 512 pages freed
Freeing 40000-40200 pfn range: 512 pages freed
Freeing bad80-badf4 pfn range: 116 pages freed
Freeing badf6-bae7f pfn range: 137 pages freed
Freeing bb000-100000 pfn range: 282624 pages freed
Released 283999 pages of unused memory
Those 283999 pages are subtracted from the nr_pages and are returned
to the hypervisor. The end result is that the initial domain
boots with 1GB less memory as the nr_pages has been subtracted by
the amount of pages residing within the PCI hole. It can balloon up
to that if desired using 'xl mem-set 0 8092', but the balloon driver
is not always compiled in for the initial domain.
This patch, implements the populate hypercall (XENMEM_populate_physmap)
which increases the the domain with the same amount of pages that
were released.
The other solution (that did not work) was to transplant the MFN in
the P2M tree - the ones that were going to be freed were put in
the E820_RAM regions past the nr_pages. But the modifications to the
M2P array (the other side of creating PTEs) were not carried away.
As the hypervisor is the only one capable of modifying that and the
only two hypercalls that would do this are: the update_va_mapping
(which won't work, as during initial bootup only PFNs up to nr_pages
are mapped in the guest) or via the populate hypercall.
The end result is that the kernel can now boot with the
nr_pages without having to subtract the 283999 pages.
On a 8GB machine, with various dom0_mem= parameters this is what we get:
no dom0_mem
-Memory: 6485264k/9435136k available (5817k kernel code, 1136060k absent, 1813812k reserved, 2899k data, 696k init)
+Memory: 7619036k/9435136k available (5817k kernel code, 1136060k absent, 680040k reserved, 2899k data, 696k init)
dom0_mem=3G
-Memory: 2616536k/9435136k available (5817k kernel code, 1136060k absent, 5682540k reserved, 2899k data, 696k init)
+Memory: 2703776k/9435136k available (5817k kernel code, 1136060k absent, 5595300k reserved, 2899k data, 696k init)
dom0_mem=max:3G
-Memory: 2696732k/4281724k available (5817k kernel code, 1136060k absent, 448932k reserved, 2899k data, 696k init)
+Memory: 2702204k/4281724k available (5817k kernel code, 1136060k absent, 443460k reserved, 2899k data, 696k init)
And the 'xm list' or 'xl list' now reflect what the dom0_mem=
argument is.
Acked-by: David Vrabel <david.vrabel@citrix.com>
[v2: Use populate hypercall]
[v3: Remove debug printks]
[v4: Simplify code]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Otherwise we can get these meaningless:
Freeing bad80-badf4 pfn range: 0 pages freed
We also can do this for the summary ones - no point of printing
"Set 0 page(s) to 1-1 mapping"
Acked-by: David Vrabel <david.vrabel@citrix.com>
[v1: Extended to the summary printks]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
The accessing PCI configuration space with the PCI BIOS32 service does
not work in PV guests.
On systems without MMCONFIG or where the BIOS hasn't marked the
MMCONFIG region as reserved in the e820 map, the BIOS service is
probed (even though direct access is preferred) and this hangs.
CC: stable@kernel.org
Acked-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
[v1: Fixed compile error when CONFIG_PCI is not set]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
If I try to do "cat /sys/kernel/debug/kernel_page_tables"
I end up with:
BUG: unable to handle kernel paging request at ffffc7fffffff000
IP: [<ffffffff8106aa51>] ptdump_show+0x221/0x480
PGD 0
Oops: 0000 [#1] SMP
CPU 0
.. snip..
RAX: 0000000000000000 RBX: ffffc00000000fff RCX: 0000000000000000
RDX: 0000800000000000 RSI: 0000000000000000 RDI: ffffc7fffffff000
which is due to the fact we are trying to access a PFN that is not
accessible to us. The reason (at least in this case) was that
PGD[256] is set to __HYPERVISOR_VIRT_START which was setup (by the
hypervisor) to point to a read-only linear map of the MFN->PFN array.
During our parsing we would get the MFN (a valid one), try to look
it up in the MFN->PFN tree and find it invalid and return ~0 as PFN.
Then pte_mfn_to_pfn would happilly feed that in, attach the flags
and return it back to the caller. 'ptdump_show' bitshifts it and
gets and invalid value that it tries to dereference.
Instead of doing all of that, we detect the ~0 case and just
return !_PAGE_PRESENT.
This bug has been in existence .. at least until 2.6.37 (yikes!)
CC: stable@kernel.org
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
On x86_64 on AMD machines where the first APIC_ID is not zero, we get:
ACPI: LAPIC (acpi_id[0x01] lapic_id[0x10] enabled)
BIOS bug: APIC version is 0 for CPU 1/0x10, fixing up to 0x10
BIOS bug: APIC version mismatch, boot CPU: 0, CPU 1: version 10
which means that when the ACPI processor driver loads and
tries to parse the _Pxx states it fails to do as, as it
ends up calling acpi_get_cpuid which does this:
for_each_possible_cpu(i) {
if (cpu_physical_id(i) == apic_id)
return i;
}
And the bootup CPU, has not been found so it fails and returns -1
for the first CPU - which then subsequently in the loop that
"acpi_processor_get_info" does results in returning an error, which
means that "acpi_processor_add" failing and per_cpu(processor)
is never set (and is NULL).
That means that when xen-acpi-processor tries to load (much much
later on) and parse the P-states it gets -ENODEV from
acpi_processor_register_performance() (which tries to read
the per_cpu(processor)) and fails to parse the data.
Reported-by-and-Tested-by: Stefan Bader <stefan.bader@canonical.com>
Suggested-by: Boris Ostrovsky <boris.ostrovsky@amd.com>
[v2: Bit-shift APIC ID by 24 bits]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Implements xen_io_apic_read with hypercall, so it returns proper
IO-APIC information instead of fabricated one.
Fallback to return an emulated IO_APIC values if hypercall fails.
[v2: fallback to return an emulated IO_APIC values if hypercall fails]
Signed-off-by: Lin Ming <mlin@ss.pku.edu.cn>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This reverts commit 2531d64b6f.
The two patches:
x86/apic: Replace io_apic_ops with x86_io_apic_ops.
xen/x86: Implement x86_apic_ops
take care of fixing it properly.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Linus Torvalds
Stefano Stabellini
Andre Przywara
Konrad Rzeszutek Wilk
Konrad Rzeszutek Wilk
Ingo Molnar
Thomas Gleixner
Lin Ming
Ben Guthro
David Vrabel
David Vrabel