Load late binding firmware
v2:
- s/EAGAIN/EBUSY/
- Flush worker in suspend and driver unload (Daniele)
v3:
- Use retry interval of 6s, in steps of 200ms, to allow
other OS components release MEI CL handle (Sasha)
v4:
- return -ENODEV if component not added (Daniele)
- parse and print status returned by csc
v5:
- Use payload to check firmware valid (Daniele)
- Obtain the RPM reference before scheduling the worker to
ensure the device remains awake until the worker completes
firmware loading (Rodrigo)
v6:
- In case of error donot re-attempt fw download (Daniele)
v7 (Rodrigo):
- Rename of mei structs and callback.
Signed-off-by: Badal Nilawar <badal.nilawar@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://lore.kernel.org/r/20250905154953.3974335-6-badal.nilawar@intel.com
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Search for late binding firmware binaries and populate the meta data of
firmware structures.
v2 (Daniele):
- drm_err if firmware size is more than max pay load size
- s/request_firmware/firmware_request_nowarn/ as firmware will
not be available for all possible cards
v3 (Daniele):
- init firmware from within xe_late_bind_init, propagate error
- switch late_bind_fw to array to handle multiple firmware types
v4 (Daniele):
- Alloc payload dynamically, fix nits
v6 (Daniele)
- %s/MAX_PAYLOAD_SIZE/XE_LB_MAX_PAYLOAD_SIZE/
Signed-off-by: Badal Nilawar <badal.nilawar@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://lore.kernel.org/r/20250905154953.3974335-5-badal.nilawar@intel.com
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Introduce xe_late_bind_fw to enable firmware loading for the devices,
such as the fan controller, during the driver probe. Typically,
firmware for such devices are part of IFWI flash image but can be
replaced at probe after OEM tuning.
This patch binds mei late binding component to enable firmware loading.
v2:
- Add devm_add_action_or_reset to remove the component (Daniele)
- Add INTEL_MEI_GSC check in xe_late_bind_init() (Daniele)
v3:
- Fail driver probe if late bind initialization fails,
add has_late_bind flag (Daniele)
v4:
- %s/I915_COMPONENT_LATE_BIND/INTEL_COMPONENT_LATE_BIND/
v6:
- rebased
v7:
- rebased
- In xe_late_bind_init, use drm_err when returning an error to
stop the probe (Lucas)
- Use imperative mode in commit message (Lucas)
Signed-off-by: Badal Nilawar <badal.nilawar@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://lore.kernel.org/r/20250905154953.3974335-4-badal.nilawar@intel.com
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Introduce a new MEI client driver to support Late Binding firmware
upload/update for Intel discrete graphics platforms.
Late Binding is a runtime firmware upload/update mechanism that allows
payloads, such as fan control and voltage regulator, to be securely
delivered and applied without requiring SPI flash updates or
system reboots. This driver enables the Xe graphics driver and other
user-space tools to push such firmware blobs to the authentication
firmware via the MEI interface.
The driver handles authentication, versioning, and communication
with the authentication firmware, which in turn coordinates with
the PUnit/PCODE to apply the payload.
This is a foundational component for enabling dynamic, secure,
and re-entrant configuration updates on platforms like Battlemage.
Cc: Badal Nilawar <badal.nilawar@intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Badal Nilawar <badal.nilawar@intel.com>
Reviewed-by: Anshuman Gupta <anshuman.gupta@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20250905154953.3974335-3-badal.nilawar@intel.com
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Alexander Usyskin <alexander.usyskin@intel.com> says:
When discrete graphic card enters D3cold th CSC engine is powered down.
On wakeup from the D3cold full HECI link reset is required. The driver
should detect that firmware requests link reset and initiate the link
reset flow.
In the usual flow the connect IOCTL will trigger the wake from D3cold
and corresponding link reset. The MEI driver invalidates all open
handles on link reset including the one that triggered the wake
rendering this connection unusable. To break this loop make connect
detect that it is interrupted by link reset and retry connect attempt
after reset was completed.
Link: https://lore.kernel.org/r/20250918130435.3327400-1-alexander.usyskin@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Driver can receive HW not ready interrupt unexpectedly.
E.g. for cards that go donwn to D3cold.
Trigger link reset in this case to synchronize driver and
firmware state.
No need to do that sync if driver is going down or interrupt is
received before driver started initial link reset sequence.
Introduce UNINITIALIZED device state to allow interrupt handler
to ignore interrupts before first init.
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20250918130435.3327400-2-alexander.usyskin@intel.com
When running task_work for an exiting task, rather than perform the
issue retry attempt, the task_work is canceled. However, this isn't
done for a ring that has been closed. This can lead to requests being
successfully completed post the ring being closed, which is somewhat
confusing and surprising to an application.
Rather than just check the task exit state, also include the ring
ref state in deciding whether or not to terminate a given request when
run from task_work.
Cc: stable@vger.kernel.org # 6.1+
Link: https://github.com/axboe/liburing/discussions/1459
Reported-by: Benedek Thaler <thaler@thaler.hu>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pull x86 platform driver fixes from Ilpo Järvinen:
"Fixes and new HW support:
- amd/pmc: Add MECHREVO Yilong15Pro to spurious_8042 list
- amd/pmf: Support new ACPI ID AMDI0108
- asus-wmi: Re-add extra keys to ignore_key_wlan quirk
- oxpec: Add support for AOKZOE A1X and OneXPlayer X1Pro EVA-02"
* tag 'platform-drivers-x86-v6.17-4' of git://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86:
platform/x86: asus-wmi: Re-add extra keys to ignore_key_wlan quirk
platform/x86/amd/pmf: Support new ACPI ID AMDI0108
platform/x86: oxpec: Add support for AOKZOE A1X
platform/x86: oxpec: Add support for OneXPlayer X1Pro EVA-02
platform/x86/amd/pmc: Add MECHREVO Yilong15Pro to spurious_8042 list
The regex in this block of code makes no sense, and a quick test shows that
it never matches anything; simply delete the code.
No output changes.
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Add some more comments to dump_function(), add some comments, and trim out
an unneeded duplicate output_declaration() call.
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
The logic to handle macros is split in dump_function(); bring it all
together into a single place and add a comment saying what's going on.
Remove the unneeded is_define_proto variable, and tighten up the code
a bit.
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
The regexes for the parsing of function prototypes were more complicated
than they needed to be and difficult to understand -- at least, I spent a
fair amount of time bashing my head against them. Simplify them, and add
some documentation comments as well.
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
The is_define_proto case in dump_function() uses a regex with an empty
capture group - () - that has no use; just take it out.
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
The "name" regex in dump_function() includes both the tilde and colon
characters, but neither has any place in function prototypes. Remove the
characters, after which the regex simplifies to "\w+"
No output changes.
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Both functions and structs are passed through a set of regex-based
transforms, but the two were structured differently, despite being the same
thing. Create a utility function to apply transformations and use it in
both cases.
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Move these definitions to file level, where they are executed once, and
don't clutter the function itself.
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
The handling of untyped parameters involved a number of redundant tests;
restructure the code to remove them and be more compact.
No output changes.
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
The special case for __cacheline_group_begin/end() can be handled by just
adding another pattern to the struct_prefixes, eliminating the need for a
special case in push_parameter().
One change is that these annotations no longer appear in the rendered
output, just like all the other annotations that we clean out.
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Pull UML fixes from Johannes Berg:
"A few fixes for UML, which I'd meant to send earlier but then forgot.
All of them are pretty long-standing issues that are either not really
happening (the UAF), in rarely used code (the FD buffer issue), or an
issue only for some host configurations (the executable stack):
- mark stack not executable to work on more modern systems with
selinux
- fix use-after-free in a virtio error path
- fix stack buffer overflow in external unix socket FD receive
function"
* tag 'uml-for-6.17-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux:
um: Fix FD copy size in os_rcv_fd_msg()
um: virtio_uml: Fix use-after-free after put_device in probe
um: Don't mark stack executable
KVM needs to ensure the guest hypervisor's traps take effect when the
vCPU is in a nested context. While supporting infrastructure is in place
for most of the EL2 trap registers, MDCR_EL2 is not.
Fold the guest's trap configuration into the effective MDCR_EL2. Apply
it directly to the in-memory representation as it gets recomputed on
every vcpu_load() anyway.
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
In case you haven't realized it yet, the architecture is _slightly_
broken in the context of nested virt. Here we have another example of
FEAT_NV2 redirecting a sysreg (MDSCR_EL1) to memory that actually
affects execution at vEL2.
Fortunately, MDCR_EL2.TDA provides the necessary traps to hide this
mess at the expense of unnecessarily trapping the breakpoint/watchpoint
registers. Yes, FEAT_FGT gives us a precise trap but let's just opt for
obvious correctness to start.
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
For regular block devices using the zoned allocator, the default
maximum number of open zones is set to 1/4 of the number of realtime
groups. For a large capacity device, this leads to a very large limit.
E.g. with a 26 TB HDD:
mount /dev/sdb /mnt
...
XFS (sdb): 95836 zones of 65536 blocks size (23959 max open)
In turn such large limit on the number of open zones can lead, depending
on the workload, on a very large number of concurrent write streams
which devices generally do not handle well, leading to poor performance.
Introduce the default limit XFS_DEFAULT_MAX_OPEN_ZONES, defined as 128
to match the hardware limit of most SMR HDDs available today, and use
this limit to set mp->m_max_open_zones in xfs_calc_open_zones() instead
of calling xfs_max_open_zones(), when the user did not specify a limit
with the max_open_zones mount option.
For the 26 TB HDD example, we now get:
mount /dev/sdb /mnt
...
XFS (sdb): 95836 zones of 65536 blocks (128 max open zones)
This change does not prevent the user from specifying a lareger number
for the open zones limit. E.g.
mount -o max_open_zones=4096 /dev/sdb /mnt
...
XFS (sdb): 95836 zones of 65536 blocks (4096 max open zones)
Finally, since xfs_calc_open_zones() checks and caps the
mp->m_max_open_zones limit against the value calculated by
xfs_max_open_zones() for any type of device, this new default limit does
not increase m_max_open_zones for small capacity devices.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
Reword the information message displayed in xfs_mount_zones()
indicating the total zone count and maximum number of open zones.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
Right now 5 places in the kernel and one in xfsprogs need to be updated
for each new error tag. Add a bit of macro magic so that only the
error tag definition and a single table, which reside next to each
other, need to be updated.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
Don't pass expr to XFS_TEST_ERROR. Most calls pass a constant false,
and the places that do pass an expression become cleaner by moving it
out.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
xfs_errortag_set is only called by xfs_errortag_attr_store, , which does
not need to validate the error tag, because it can only be called on
valid error tags that had a sysfs attribute registered.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
xfs_errortag_get is only called by xfs_errortag_attr_show, which does not
need to validate the error tag, because it can only be called on valid
error tags that had a sysfs attribute registered.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
A process might fail to allocate a new bitmap when trying to expand its
proc->dmap. In that case, dbitmap_grow() fails and frees the old bitmap
via dbitmap_free(). However, the driver calls dbitmap_free() again when
the same process terminates, leading to a double-free error:
==================================================================
BUG: KASAN: double-free in binder_proc_dec_tmpref+0x2e0/0x55c
Free of addr ffff00000b7c1420 by task kworker/9:1/209
CPU: 9 UID: 0 PID: 209 Comm: kworker/9:1 Not tainted 6.17.0-rc6-dirty #5 PREEMPT
Hardware name: linux,dummy-virt (DT)
Workqueue: events binder_deferred_func
Call trace:
kfree+0x164/0x31c
binder_proc_dec_tmpref+0x2e0/0x55c
binder_deferred_func+0xc24/0x1120
process_one_work+0x520/0xba4
[...]
Allocated by task 448:
__kmalloc_noprof+0x178/0x3c0
bitmap_zalloc+0x24/0x30
binder_open+0x14c/0xc10
[...]
Freed by task 449:
kfree+0x184/0x31c
binder_inc_ref_for_node+0xb44/0xe44
binder_transaction+0x29b4/0x7fbc
binder_thread_write+0x1708/0x442c
binder_ioctl+0x1b50/0x2900
[...]
==================================================================
Fix this issue by marking proc->map NULL in dbitmap_free().
Cc: stable@vger.kernel.org
Fixes: 15d9da3f81 ("binder: use bitmap for faster descriptor lookup")
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Tiffany Yang <ynaffit@google.com>
Link: https://lore.kernel.org/r/20250915221248.3470154-1-cmllamas@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The original code relies on cancel_delayed_work() in otx2_ptp_destroy(),
which does not ensure that the delayed work item synctstamp_work has fully
completed if it was already running. This leads to use-after-free scenarios
where otx2_ptp is deallocated by otx2_ptp_destroy(), while synctstamp_work
remains active and attempts to dereference otx2_ptp in otx2_sync_tstamp().
Furthermore, the synctstamp_work is cyclic, the likelihood of triggering
the bug is nonnegligible.
A typical race condition is illustrated below:
CPU 0 (cleanup) | CPU 1 (delayed work callback)
otx2_remove() |
otx2_ptp_destroy() | otx2_sync_tstamp()
cancel_delayed_work() |
kfree(ptp) |
| ptp = container_of(...); //UAF
| ptp-> //UAF
This is confirmed by a KASAN report:
BUG: KASAN: slab-use-after-free in __run_timer_base.part.0+0x7d7/0x8c0
Write of size 8 at addr ffff88800aa09a18 by task bash/136
...
Call Trace:
<IRQ>
dump_stack_lvl+0x55/0x70
print_report+0xcf/0x610
? __run_timer_base.part.0+0x7d7/0x8c0
kasan_report+0xb8/0xf0
? __run_timer_base.part.0+0x7d7/0x8c0
__run_timer_base.part.0+0x7d7/0x8c0
? __pfx___run_timer_base.part.0+0x10/0x10
? __pfx_read_tsc+0x10/0x10
? ktime_get+0x60/0x140
? lapic_next_event+0x11/0x20
? clockevents_program_event+0x1d4/0x2a0
run_timer_softirq+0xd1/0x190
handle_softirqs+0x16a/0x550
irq_exit_rcu+0xaf/0xe0
sysvec_apic_timer_interrupt+0x70/0x80
</IRQ>
...
Allocated by task 1:
kasan_save_stack+0x24/0x50
kasan_save_track+0x14/0x30
__kasan_kmalloc+0x7f/0x90
otx2_ptp_init+0xb1/0x860
otx2_probe+0x4eb/0xc30
local_pci_probe+0xdc/0x190
pci_device_probe+0x2fe/0x470
really_probe+0x1ca/0x5c0
__driver_probe_device+0x248/0x310
driver_probe_device+0x44/0x120
__driver_attach+0xd2/0x310
bus_for_each_dev+0xed/0x170
bus_add_driver+0x208/0x500
driver_register+0x132/0x460
do_one_initcall+0x89/0x300
kernel_init_freeable+0x40d/0x720
kernel_init+0x1a/0x150
ret_from_fork+0x10c/0x1a0
ret_from_fork_asm+0x1a/0x30
Freed by task 136:
kasan_save_stack+0x24/0x50
kasan_save_track+0x14/0x30
kasan_save_free_info+0x3a/0x60
__kasan_slab_free+0x3f/0x50
kfree+0x137/0x370
otx2_ptp_destroy+0x38/0x80
otx2_remove+0x10d/0x4c0
pci_device_remove+0xa6/0x1d0
device_release_driver_internal+0xf8/0x210
pci_stop_bus_device+0x105/0x150
pci_stop_and_remove_bus_device_locked+0x15/0x30
remove_store+0xcc/0xe0
kernfs_fop_write_iter+0x2c3/0x440
vfs_write+0x871/0xd70
ksys_write+0xee/0x1c0
do_syscall_64+0xac/0x280
entry_SYSCALL_64_after_hwframe+0x77/0x7f
...
Replace cancel_delayed_work() with cancel_delayed_work_sync() to ensure
that the delayed work item is properly canceled before the otx2_ptp is
deallocated.
This bug was initially identified through static analysis. To reproduce
and test it, I simulated the OcteonTX2 PCI device in QEMU and introduced
artificial delays within the otx2_sync_tstamp() function to increase the
likelihood of triggering the bug.
Fixes: 2958d17a89 ("octeontx2-pf: Add support for ptp 1-step mode on CN10K silicon")
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Reviewed-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The original code uses cancel_delayed_work() in cnic_cm_stop_bnx2x_hw(),
which does not guarantee that the delayed work item 'delete_task' has
fully completed if it was already running. Additionally, the delayed work
item is cyclic, the flush_workqueue() in cnic_cm_stop_bnx2x_hw() only
blocks and waits for work items that were already queued to the
workqueue prior to its invocation. Any work items submitted after
flush_workqueue() is called are not included in the set of tasks that the
flush operation awaits. This means that after the cyclic work items have
finished executing, a delayed work item may still exist in the workqueue.
This leads to use-after-free scenarios where the cnic_dev is deallocated
by cnic_free_dev(), while delete_task remains active and attempt to
dereference cnic_dev in cnic_delete_task().
A typical race condition is illustrated below:
CPU 0 (cleanup) | CPU 1 (delayed work callback)
cnic_netdev_event() |
cnic_stop_hw() | cnic_delete_task()
cnic_cm_stop_bnx2x_hw() | ...
cancel_delayed_work() | /* the queue_delayed_work()
flush_workqueue() | executes after flush_workqueue()*/
| queue_delayed_work()
cnic_free_dev(dev)//free | cnic_delete_task() //new instance
| dev = cp->dev; //use
Replace cancel_delayed_work() with cancel_delayed_work_sync() to ensure
that the cyclic delayed work item is properly canceled and that any
ongoing execution of the work item completes before the cnic_dev is
deallocated. Furthermore, since cancel_delayed_work_sync() uses
__flush_work(work, true) to synchronously wait for any currently
executing instance of the work item to finish, the flush_workqueue()
becomes redundant and should be removed.
This bug was identified through static analysis. To reproduce the issue
and validate the fix, I simulated the cnic PCI device in QEMU and
introduced intentional delays — such as inserting calls to ssleep()
within the cnic_delete_task() function — to increase the likelihood
of triggering the bug.
Fixes: fdf24086f4 ("cnic: Defer iscsi connection cleanup")
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
devlink_rate_node_get_by_name() and devlink_rate_nodes_destroy() have a
couple of unnecessary static variables for iterating over devlink rates.
This could lead to races/corruption/unhappiness if two concurrent
operations execute the same function.
Remove 'static' from both. It's amazing this was missed for 4+ years.
While at it, I confirmed there are no more examples of this mistake in
net/ with 1, 2 or 3 levels of indentation.
Fixes: a8ecb93ef0 ("devlink: Introduce rate nodes")
Signed-off-by: Cosmin Ratiu <cratiu@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The expression `(conf->instr_type == 64) << iq_no` can overflow because
`iq_no` may be as high as 64 (`CN23XX_MAX_RINGS_PER_PF`). Casting the
operand to `u64` ensures correct 64-bit arithmetic.
Fixes: f21fb3ed36 ("Add support of Cavium Liquidio ethernet adapters")
Signed-off-by: Alexey Nepomnyashih <sdl@nppct.ru>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Cast nr_pages to unsigned long to avoid overflow when handling large
AUX buffer sizes (>= 2 GiB).
Fixes: d5d9696b03 ("drivers/perf: Add support for ARMv8.2 Statistical Profiling Extension")
Signed-off-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Cast nr_pages to unsigned long to avoid overflow when handling large
AUX buffer sizes (>= 2 GiB).
Fixes: 3fbf7f011f ("coresight: sink: Add TRBE driver")
Signed-off-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>