[ Upstream commit 6f03055d50 ]
The MIPS BMC63XX subarch does not provide/support clk_set_parent().
This causes build errors in a few drivers, so add a simple implementation
of that function so that callers of it will build without errors.
Fixes these build errors:
ERROR: modpost: "clk_set_parent" [sound/soc/jz4740/snd-soc-jz4740-i2s.ko] undefined!
ERROR: modpost: "clk_set_parent" [sound/soc/atmel/snd-soc-atmel-i2s.ko] undefined!
Fixes: e7300d04bd ("MIPS: BCM63xx: Add support for the Broadcom BCM63xx family of SOCs." )
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 2355028c0c ]
Originally, the conditions for preventing reentry are not correct.
dai->component->active is not the state specifically for pcmif dai, so it
is not a correct condition to indicate the status of pcmif dai.
On the other hand, snd_soc_dai_stream_actvie() in prepare ops for both
playback and capture possibly return true at the first entry when these
two streams are opened at the same time.
In the patch, I refer to the implementation in mt8192-dai-pcm.c.
Clock and enabling bit for PCMIF are managed by DAPM, and the condition
for prepare ops is replaced by the status of dai widget.
Fixes: 1f95c01911 ("ASoC: mediatek: mt8195: support pcm in platform driver")
Signed-off-by: Trevor Wu <trevor.wu@mediatek.com>
Link: https://lore.kernel.org/r/20211230084731.31372-2-trevor.wu@mediatek.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit fcee5ce50b ]
When firmware load failed, kernel report task hung as follows:
INFO: task xrun:5191 blocked for more than 147 seconds.
Tainted: G W 5.16.0-rc5-next-20211220+ #11
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:xrun state:D stack: 0 pid: 5191 ppid: 270 flags:0x00000004
Call Trace:
__schedule+0xc12/0x4b50 kernel/sched/core.c:4986
schedule+0xd7/0x260 kernel/sched/core.c:6369 (discriminator 1)
schedule_timeout+0x7aa/0xa80 kernel/time/timer.c:1857
wait_for_completion+0x181/0x290 kernel/sched/completion.c:85
lattice_ecp3_remove+0x32/0x40 drivers/misc/lattice-ecp3-config.c:221
spi_remove+0x72/0xb0 drivers/spi/spi.c:409
lattice_ecp3_remove() wait for signals from firmware loading, but when
load failed, firmware_load() does not send this signal. This cause
device remove hung. Fix it by sending signal even if load failed.
Fixes: 781551df57 ("misc: Add Lattice ECP3 FPGA configuration via SPI")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Link: https://lore.kernel.org/r/20211228125522.3122284-1-weiyongjun1@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit fd1eaaaaa6 ]
When CONFIG_PPC_RFI_SRR_DEBUG=y we check the SRR values before returning
from interrupts. This is done in asm using EMIT_BUG_ENTRY, and passing
BUGFLAG_WARNING.
However that fails to create an exception table entry for the warning,
and so do_program_check() fails the exception table search and proceeds
to call _exception(), resulting in an oops like:
Oops: Exception in kernel mode, sig: 5 [#1]
LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries
Modules linked in:
CPU: 2 PID: 1204 Comm: sigreturn_unali Tainted: P 5.16.0-rc2-00194-g91ca3d4f77c5 #12
NIP: c00000000000c5b0 LR: 0000000000000000 CTR: 0000000000000000
...
NIP [c00000000000c5b0] system_call_common+0x150/0x268
LR [0000000000000000] 0x0
Call Trace:
[c00000000db73e10] [c00000000000c558] system_call_common+0xf8/0x268 (unreliable)
...
Instruction dump:
7cc803a6 888d0931 2c240000 4082001c 38800000 988d0931 e8810170 e8a10178
7c9a03a6 7cbb03a6 7d7a02a6 e9810170 <7f0b6088> 7d7b02a6 e9810178 7f0b6088
We should instead use EMIT_WARN_ENTRY, which creates an exception table
entry for the warning, allowing the warning to be correctly recognised,
and the code to resume after printing the warning.
Note however that because this warning is buried deep in the interrupt
return path, we are not able to recover from it (due to MSR_RI being
clear), so we still end up in die() with an unrecoverable exception.
Fixes: 59dc5bfca0 ("powerpc/64s: avoid reloading (H)SRR registers if they are still valid")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211221135101.2085547-2-mpe@ellerman.id.au
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 314f6c23dd ]
When CONFIG_PPC_RFI_SRR_DEBUG=y we check that NIP and SRR0 match when
returning from interrupts. This can trigger falsely if NIP has either of
its two low bits set via sigreturn or ptrace, while SRR0 has its low two
bits masked in hardware.
As a quick fix make sure to mask the low bits before doing the check.
Fixes: 59dc5bfca0 ("powerpc/64s: avoid reloading (H)SRR registers if they are still valid")
Reported-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Tested-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
Link: https://lore.kernel.org/r/20211221135101.2085547-1-mpe@ellerman.id.au
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 6e1fcab00a ]
John Garry reported a deadlock that occurs when trying to access a
runtime-suspended SATA device. For obscure reasons, the rescan procedure
causes the link to be hard-reset, which disconnects the device.
The rescan tries to carry out a runtime resume when accessing the device.
scsi_rescan_device() holds the SCSI device lock and won't release it until
it can put commands onto the device's block queue. This can't happen until
the queue is successfully runtime-resumed or the device is unregistered.
But the runtime resume fails because the device is disconnected, and
__scsi_remove_device() can't do the unregistration because it can't get the
device lock.
The best way to resolve this deadlock appears to be to allow the block
queue to start running again even after an unsuccessful runtime resume.
The idea is that the driver or the SCSI error handler will need to be able
to use the queue to resolve the runtime resume failure.
This patch removes the err argument to blk_post_runtime_resume() and makes
the routine act as though the resume was successful always. This fixes the
deadlock.
Link: https://lore.kernel.org/r/1639999298-244569-4-git-send-email-chenxiang66@hisilicon.com
Fixes: e27829dc92 ("scsi: serialize ->rescan against ->remove")
Reported-and-tested-by: John Garry <john.garry@huawei.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 30e693ee82 ]
mt8195_cg_patch is used to reset the default value of audio cg, so the
register value could be consistent with CCF reference count.
Nevertheless, AUDIO_TOP_CON1[1:0] is used to control an internal mux,
and it's expected to keep the default value 0.
This patch corrects the default value in case an unexpected behavior
happens in the future.
Fixes: 6746cc8582 ("ASoC: mediatek: mt8195: add platform driver")
Signed-off-by: Trevor Wu <trevor.wu@mediatek.com>
Link: https://lore.kernel.org/r/20211216022424.28470-1-trevor.wu@mediatek.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit d7061627d7 ]
It turns out to be possible for hotplugging out a device to reach the
stage of tearing down the device's group and default domain before the
domain's flush queue has drained naturally. At this point, it is then
possible for the timeout to expire just before the del_timer() call
in free_iova_flush_queue(), such that we then proceed to free the FQ
resources while fq_flush_timeout() is still accessing them on another
CPU. Crashes due to this have been observed in the wild while removing
NVMe devices.
Close the race window by using del_timer_sync() to safely wait for any
active timeout handler to finish before we start to free things. We
already avoid any locking in free_iova_flush_queue() since the FQ is
supposed to be inactive anyway, so the potential deadlock scenario does
not apply.
Fixes: 9a005a800a ("iommu/iova: Add flush timer")
Reviewed-by: John Garry <john.garry@huawei.com>
Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
[ rm: rewrite commit message ]
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/0a365e5b07f14b7344677ad6a9a734966a8422ce.1639753638.git.robin.murphy@arm.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 1980105e3c ]
Use IRQCHIP_MASK_ON_SUSPEND to make the core irq code to
mask the iommu interrupt on suspend and unmask it on the resume.
Since now the unmask function updates the INTX settings,
that will restore them on resume from s3/s4.
Since IRQCHIP_MASK_ON_SUSPEND is only effective for interrupts
which are not wakeup sources, remove IRQCHIP_SKIP_SET_WAKE flag
and instead implement a dummy .irq_set_wake which doesn't allow
the interrupt to become a wakeup source.
Fixes: 6692981295 ("iommu/amd: Add support for X2APIC IOMMU interrupts")
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Link: https://lore.kernel.org/r/20211123161038.48009-5-mlevitsk@redhat.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit a670c82d9c ]
Commit d4a451d5fc ("arch: remove the ARCH_PHYS_ADDR_T_64BIT config
symbol") removes config ARCH_PHYS_ADDR_T_64BIT with all instances of that
config refactored appropriately. Since then, it is recommended to use the
config PHYS_ADDR_T_64BIT instead.
Commit 171543e752 ("MIPS: Disallow CPU_SUPPORTS_HUGEPAGES for XPA,EVA")
introduces the expression "!(32BIT && (ARCH_PHYS_ADDR_T_64BIT || EVA))"
for config CPU_SUPPORTS_HUGEPAGES, which unintentionally refers to the
non-existing symbol ARCH_PHYS_ADDR_T_64BIT instead of the intended
PHYS_ADDR_T_64BIT.
Fix this Kconfig reference to the intended PHYS_ADDR_T_64BIT.
This issue was identified with the script ./scripts/checkkconfigsymbols.py.
I then reported it on the mailing list and Paul confirmed the mistake in
the linked email thread.
Link: https://lore.kernel.org/lkml/H8IU3R.H5QVNRA077PT@crapouillou.net/
Suggested-by: Paul Cercueil <paul@crapouillou.net>
Fixes: 171543e752 ("MIPS: Disallow CPU_SUPPORTS_HUGEPAGES for XPA,EVA")
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit fd4eb90b16 ]
Commit ab7c01fdc3 ("mips: Add MIPS Release 5 support") adds the two
configs CPU_MIPS32_R5 and CPU_MIPS64_R5, which depend on the corresponding
SYS_HAS_CPU_MIPS32_R5 and SYS_HAS_CPU_MIPS64_R5, respectively.
The config SYS_HAS_CPU_MIPS32_R5 was already introduced with commit
c5b367835c ("MIPS: Add support for XPA."); the config
SYS_HAS_CPU_MIPS64_R5, however, was never introduced.
Hence, ./scripts/checkkconfigsymbols.py warns:
SYS_HAS_CPU_MIPS64_R5
Referencing files: arch/mips/Kconfig, arch/mips/include/asm/cpu-type.h
Add the definition for config SYS_HAS_CPU_MIPS64_R5 under the assumption
that SYS_HAS_CPU_MIPS64_R5 follows the same pattern as the existing
SYS_HAS_CPU_MIPS32_R5 and SYS_HAS_CPU_MIPS64_R6.
Fixes: ab7c01fdc3 ("mips: Add MIPS Release 5 support")
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit a8d61a9112 ]
The struct device variable "dev_bogus" was triggering this warning
on a PowerPC build:
drivers/of/unittest.c: In function 'of_unittest_dma_ranges_one.constprop':
[...] >> The frame size of 1424 bytes is larger than 1024 bytes
[-Wframe-larger-than=]
This variable is now dynamically allocated.
Fixes: e0d072782c ("dma-mapping: introduce DMA range map, supplanting dma_pfn_offset")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Jim Quinlan <jim2101024@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Frank Rowand <frank.rowand@sony.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20211210184636.7273-2-jim2101024@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 20679094a0 ]
Currently, when cma_resolve_ib_dev() searches for a matching GID it will
stop searching after encountering the first empty GID table entry. This
behavior is wrong since neither IB nor RoCE spec enforce tightly packed
GID tables.
For example, when the matching valid GID entry exists at index N, and if a
GID entry is empty at index N-1, cma_resolve_ib_dev() will fail to find
the matching valid entry.
Fix it by making cma_resolve_ib_dev() continue searching even after
encountering missing entries.
Fixes: f17df3b0de ("RDMA/cma: Add support for AF_IB to rdma_resolve_addr()")
Link: https://lore.kernel.org/r/b7346307e3bb396c43d67d924348c6c496493991.1639055490.git.leonro@nvidia.com
Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Mark Zhang <markzhang@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 483d805191 ]
Currently, ib_find_gid() will stop searching after encountering the first
empty GID table entry. This behavior is wrong since neither IB nor RoCE
spec enforce tightly packed GID tables.
For example, when a valid GID entry exists at index N, and if a GID entry
is empty at index N-1, ib_find_gid() will fail to find the valid entry.
Fix it by making ib_find_gid() continue searching even after encountering
missing entries.
Fixes: 5eb620c81c ("IB/core: Add helpers for uncached GID and P_Key searches")
Link: https://lore.kernel.org/r/e55d331b96cecfc2cf19803d16e7109ea966882d.1639055490.git.leonro@nvidia.com
Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Mark Zhang <markzhang@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 29bbc35e29 ]
pci_irq_vector() and pci_irq_get_affinity() use the list position to find the
MSI-X descriptor at a given index. That's correct for the normal case where
the entry number is the same as the list position.
But it's wrong for cases where MSI-X was allocated with an entries array
describing sparse entry numbers into the hardware message descriptor
table. That's inconsistent at best.
Make it always check the entry number because that's what the zero base
index really means. This change won't break existing users which use a
sparse entries array for allocation because these users retrieve the Linux
interrupt number from the entries array after allocation and none of them
uses pci_irq_vector() or pci_irq_get_affinity().
Fixes: aff171641d ("PCI: Provide sensible IRQ vector alloc/free routines")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20211206210223.929792157@linutronix.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 9abe2ac834 ]
Table descriptors were being installed without properly formatting the
address using paddr_to_iopte, which does not match up with the
iopte_deref in __arm_lpae_map. This is incorrect for the LPAE pte
format, as it does not handle the high bits properly.
This was found on Apple T6000 DARTs, which require a new pte format
(different shift); adding support for that to
paddr_to_iopte/iopte_to_paddr caused it to break badly, as even <48-bit
addresses would end up incorrect in that case.
Fixes: 6c89928ff7 ("iommu/io-pgtable-arm: Support 52-bit physical address")
Acked-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Hector Martin <marcan@marcan.st>
Link: https://lore.kernel.org/r/20211120031343.88034-1-marcan@marcan.st
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 6d98eb95b4 ]
Transactions are copied from the sender to the target
first and objects like BINDER_TYPE_PTR and BINDER_TYPE_FDA
are then fixed up. This means there is a short period where
the sender's version of these objects are visible to the
target prior to the fixups.
Instead of copying all of the data first, copy data only
after any needed fixups have been applied.
Fixes: 457b9a6f09 ("Staging: android: add binder driver")
Reviewed-by: Martijn Coenen <maco@android.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Todd Kjos <tkjos@google.com>
Link: https://lore.kernel.org/r/20211130185152.437403-3-tkjos@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit fe6b186924 ]
If a memory copy function fails to copy the whole buffer,
a positive integar with the remaining bytes is returned.
In binder_translate_fd_array() this can result in an fd being
skipped due to the failed copy, but the loop continues
processing fds since the early return condition expects a
negative integer on error.
Fix by returning "ret > 0 ? -EINVAL : ret" to handle this case.
Fixes: bb4a2e48d5 ("binder: return errors from buffer copy functions")
Suggested-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Todd Kjos <tkjos@google.com>
Link: https://lore.kernel.org/r/20211130185152.437403-2-tkjos@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit f5912cc19a ]
Using MKWORD() on a byte-sized variable results in OOB read. Expand the
size of the reserved area so both MKWORD and MKBYTE continue to work
without overflow. Silences this warning on a -Warray-bounds build:
drivers/char/mwave/3780i.h:346:22: error: array subscript 'short unsigned int[0]' is partly outside array bounds of 'DSP_ISA_SLAVE_CONTROL[1]' [-Werror=array-bounds]
346 | #define MKWORD(var) (*((unsigned short *)(&var)))
| ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/char/mwave/3780i.h:356:40: note: in definition of macro 'OutWordDsp'
356 | #define OutWordDsp(index,value) outw(value,usDspBaseIO+index)
| ^~~~~
drivers/char/mwave/3780i.c:373:41: note: in expansion of macro 'MKWORD'
373 | OutWordDsp(DSP_IsaSlaveControl, MKWORD(rSlaveControl));
| ^~~~~~
drivers/char/mwave/3780i.c:358:31: note: while referencing 'rSlaveControl'
358 | DSP_ISA_SLAVE_CONTROL rSlaveControl;
| ^~~~~~~~~~~~~
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20211203084206.3104326-1-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit c86ff8c55b ]
Since commit db3a34e174 ("clocksource: Retry clock read if long delays
detected") and commit 2e27e793e2 ("clocksource: Reduce clocksource-skew
threshold"), it is found that tsc clocksource fallback to hpet can
sometimes happen on both Intel and AMD systems especially when they are
running stressful benchmarking workloads. Of the 23 systems tested with
a v5.14 kernel, 10 of them have switched to hpet clock source during
the test run.
The result of falling back to hpet is a drastic reduction of performance
when running benchmarks. For example, the fio performance tests can
drop up to 70% whereas the iperf3 performance can drop up to 80%.
4 hpet fallbacks happened during bootup. They were:
[ 8.749399] clocksource: timekeeping watchdog on CPU13: hpet read-back delay of 263750ns, attempt 4, marking unstable
[ 12.044610] clocksource: timekeeping watchdog on CPU19: hpet read-back delay of 186166ns, attempt 4, marking unstable
[ 17.336941] clocksource: timekeeping watchdog on CPU28: hpet read-back delay of 182291ns, attempt 4, marking unstable
[ 17.518565] clocksource: timekeeping watchdog on CPU34: hpet read-back delay of 252196ns, attempt 4, marking unstable
Other fallbacks happen when the systems were running stressful
benchmarks. For example:
[ 2685.867873] clocksource: timekeeping watchdog on CPU117: hpet read-back delay of 57269ns, attempt 4, marking unstable
[46215.471228] clocksource: timekeeping watchdog on CPU8: hpet read-back delay of 61460ns, attempt 4, marking unstable
Commit 2e27e793e2 ("clocksource: Reduce clocksource-skew threshold"),
changed the skew margin from 100us to 50us. I think this is too small
and can easily be exceeded when running some stressful workloads on a
thermally stressed system. So it is switched back to 100us.
Even a maximum skew margin of 100us may be too small in for some systems
when booting up especially if those systems are under thermal stress. To
eliminate the case that the large skew is due to the system being too
busy slowing down the reading of both the watchdog and the clocksource,
an extra consecutive read of watchdog clock is being done to check this.
The consecutive watchdog read delay is compared against
WATCHDOG_MAX_SKEW/2. If the delay exceeds the limit, we assume that
the system is just too busy. A warning will be printed to the console
and the clock skew check is skipped for this round.
Fixes: db3a34e174 ("clocksource: Retry clock read if long delays detected")
Fixes: 2e27e793e2 ("clocksource: Reduce clocksource-skew threshold")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>