Patch series "memcontrol selftests fixups", v2.
Flushing the patches to make memcontrol selftests check the events
behavior we had consensus about (test_memcg_low fails).
(test_memcg_reclaim, test_memcg_swap_max fail for me now but it's present
even before the refactoring.)
The two bigger changes are:
- adjustment of the protected values to make tests succeed with the given
tolerance,
- both test_memcg_low and test_memcg_min check protection of memory in
populated cgroups (actually as per Documentation/admin-guide/cgroup-v2.rst
memory.min should not apply to empty cgroups, which is not the case
currently. Therefore I unified tests with the populated case in order to to
bring more broken tests).
This patch (of 5):
This fixes mis-applied changes from commit 72b1e03aa7 ("cgroup: account
for memory_localevents in test_memcg_oom_group_leaf_events()").
Link: https://lkml.kernel.org/r/20220518161859.21565-1-mkoutny@suse.com
Link: https://lkml.kernel.org/r/20220518161859.21565-2-mkoutny@suse.com
Signed-off-by: Michal Koutný <mkoutny@suse.com>
Reviewed-by: David Vernet <void@manifault.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Richard Palethorpe <rpalethorpe@suse.de>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Think about the below scenario:
CPU1 CPU2
z3fold_page_migrate z3fold_map
z3fold_page_trylock
...
z3fold_page_unlock
/* slots still points to old zhdr*/
get_z3fold_header
get slots from handle
get old zhdr from slots
z3fold_page_trylock
return *old* zhdr
encode_handle(new_zhdr, FIRST|LAST|MIDDLE)
put_page(page) /* zhdr is freed! */
but zhdr is still used by caller!
z3fold_map can map freed z3fold page and lead to use-after-free bug. To
fix it, we add PAGE_MIGRATED to indicate z3fold page is migrated and soon
to be released. So get_z3fold_header won't return such page.
Link: https://lkml.kernel.org/r/20220429064051.61552-10-linmiaohe@huawei.com
Fixes: 1f862989b0 ("mm/z3fold.c: support page migration")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Think about the below scenario:
CPU1 CPU2
z3fold_reclaim_page z3fold_free
spin_lock(&pool->lock) get_z3fold_header -- hold page_lock
kref_get_unless_zero
kref_put--zhdr->refcount can be 1 now
!z3fold_page_trylock
kref_put -- zhdr->refcount is 0 now
release_z3fold_page
WARN_ON(!list_empty(&zhdr->buddy)); -- we're on buddy now!
spin_lock(&pool->lock); -- deadlock here!
z3fold_reclaim_page might race with z3fold_free and will lead to pool lock
deadlock and zhdr buddy non-empty warning. To fix this, defer getting the
refcount until page_lock is held just like what __z3fold_alloc does. Note
this has the side effect that we won't break the reclaim if we meet a soon
to be released z3fold page now.
Link: https://lkml.kernel.org/r/20220429064051.61552-9-linmiaohe@huawei.com
Fixes: dcf5aedb24 ("z3fold: stricter locking and more careful reclaim")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Think about the below race window:
CPU1 CPU2
z3fold_reclaim_page z3fold_free
test_and_set_bit PAGE_CLAIMED
failed to reclaim page
z3fold_page_lock(zhdr);
add back to the lru list;
z3fold_page_unlock(zhdr);
get_z3fold_header
page_claimed=test_and_set_bit PAGE_CLAIMED
clear_bit(PAGE_CLAIMED, &page->private);
if (!page_claimed) /* it's false true */
free_handle is not called
free_handle won't be called in this case. So z3fold_buddy_slots will leak.
Fix it by always clear PAGE_CLAIMED under z3fold page lock.
Link: https://lkml.kernel.org/r/20220429064051.61552-8-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Currently if z3fold couldn't find an unbuddied page it would first try to
pull a page off the stale list. But this approach is problematic. If
init z3fold page fails later, the page should be freed via
free_z3fold_page to clean up the relevant resource instead of using
__free_page directly. And if page is successfully reused, it will BUG_ON
later in __SetPageMovable because it's already non-lru movable page, i.e.
PAGE_MAPPING_MOVABLE is already set in page->mapping. In order to fix all
of these issues, we can simply remove the buggy use of stale list for
allocation because can_sleep should always be false and we never really
hit the reusing code path now.
Link: https://lkml.kernel.org/r/20220429064051.61552-4-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In the origin code, when "ExtSel" is 1, the eventcode will change to
"eventcode |= 1 << 21”. For event “UNC_Q_RxL_CREDITS_CONSUMED_VN0.DRS",
its "ExtSel" is "1", its eventcode will change from 0x1E to 0x20001E,
but in fact the eventcode should <=0x1FF, so this will cause the parse
fail:
# perf stat -e "UNC_Q_RxL_CREDITS_CONSUMED_VN0.DRS" -a sleep 0.1
event syntax error: '.._RxL_CREDITS_CONSUMED_VN0.DRS'
\___ value too big for format, maximum is 511
On the perf kernel side, the kernel assumes the valid bits are continuous.
It will adjust the 0x100 (bit 8 for perf tool) to bit 21 in HW.
DEFINE_UNCORE_FORMAT_ATTR(event_ext, event, "config:0-7,21");
So the perf tool follows the kernel side and just set bit8 other than bit21.
Fixes: fedb2b5182 ("perf jevents: Add support for parsing uncore json files")
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220525140410.1706851-1-zhengjun.xing@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Since commit d1bcae833b32f1 ("ELF: Don't generate unused section
symbols") [1], binutils (v2.36+) started dropping section symbols that
it thought were unused. This isn't an issue in general, but with
kexec_file.c, gcc is placing kexec_arch_apply_relocations[_add] into a
separate .text.unlikely section and the section symbol ".text.unlikely"
is being dropped. Due to this, recordmcount is unable to find a non-weak
symbol in .text.unlikely to generate a relocation record against.
Address this by dropping the weak attribute from these functions.
Instead, follow the existing pattern of having architectures #define the
name of the function they want to override in their headers.
[1] https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=d1bcae833b32f1
[akpm@linux-foundation.org: arch/s390/include/asm/kexec.h needs linux/module.h]
Link: https://lkml.kernel.org/r/20220519091237.676736-1-naveen.n.rao@linux.vnet.ibm.com
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Peter Pavlisko reported the following problem on kernel bugzilla 216007.
When I try to extract an uncompressed tar archive (2.6 milion
files, 760.3 GiB in size) on newly created (empty) XFS file system,
after first low tens of gigabytes extracted the process hangs in
iowait indefinitely. One CPU core is 100% occupied with iowait,
the other CPU core is idle (on 2-core Intel Celeron G1610T).
It was bisected to c9fa563072 ("xfs: use alloc_pages_bulk_array() for
buffers") but XFS is only the messenger. The problem is that nothing is
waking kswapd to reclaim some pages at a time the PCP lists cannot be
refilled until some reclaim happens. The bulk allocator checks that there
are some pages in the array and the original intent was that a bulk
allocator did not necessarily need all the requested pages and it was best
to return as quickly as possible.
This was fine for the first user of the API but both NFS and XFS require
the requested number of pages be available before making progress. Both
could be adjusted to call the page allocator directly if a bulk allocation
fails but it puts a burden on users of the API. Adjust the semantics to
attempt at least one allocation via __alloc_pages() before returning so
kswapd is woken if necessary.
It was reported via bugzilla that the patch addressed the problem and that
the tar extraction completed successfully. This may also address bug
215975 but has yet to be confirmed.
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=216007
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=215975
Link: https://lkml.kernel.org/r/20220526091210.GC3441@techsingularity.net
Fixes: 387ba26fb1 ("mm/page_alloc: add a bulk page allocator")
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: <stable@vger.kernel.org> [5.13+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The routine huge_pmd_unshare() is passed a pointer to an address
associated with an area which may be unshared. If unshare is successful
this address is updated to 'optimize' callers iterating over huge page
addresses. For the optimization to work correctly, address should be
updated to the last huge page in the unmapped/unshared area. However, in
the common case where the passed address is PUD_SIZE aligned, the address
is incorrectly updated to the address of the preceding huge page. That
wastes CPU cycles as the unmapped/unshared range is scanned twice.
Link: https://lkml.kernel.org/r/20220524205003.126184-1-mike.kravetz@oracle.com
Fixes: 39dde65c99 ("shared page table for hugetlb page")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Muchun Song <songmuchun@bytedance.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kernel function urandom_read is replaced with urandom_read_iter.
Therefore, kprobe on urandom_read is not working any more:
[root@eth50-1 bpf]# ./test_progs -n 161
test_stacktrace_build_id:PASS:skel_open_and_load 0 nsec
libbpf: kprobe perf_event_open() failed: No such file or directory
libbpf: prog 'oncpu': failed to create kprobe 'urandom_read+0x0' \
perf event: No such file or directory
libbpf: prog 'oncpu': failed to auto-attach: -2
test_stacktrace_build_id:FAIL:attach_tp err -2
161 stacktrace_build_id:FAIL
Fix this by replacing urandom_read with urandom_read_iter in the test.
Fixes: 1b388e7765 ("random: convert to using fops->read_iter()")
Reported-by: Mykola Lysenko <mykolal@fb.com>
Signed-off-by: Song Liu <song@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20220526191608.2364049-1-song@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
There is an use-after-free problem for 'eba_tbl' in ubi_create_volume()'s
error handling path:
ubi_eba_replace_table(vol, eba_tbl)
vol->eba_tbl = tbl
out_mapping:
ubi_eba_destroy_table(eba_tbl) // Free 'eba_tbl'
out_unlock:
put_device(&vol->dev)
vol_release
kfree(tbl->entries) // UAF
Fix it by removing redundant 'eba_tbl' releasing.
Fetch a reproducer in [Link].
Fixes: 493cfaeaa0 ("mtd: utilize new cdev_device_add helper function")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215965
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
UBI fetches free peb from wl_pool during wear leveling, so UBI should
check wl_pool's empty status before wear leveling. Otherwise, UBI will
miss wear leveling chances when free pebs are run out.
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
There at least 6 PEBs reserved on UBI device:
1. EBA_RESERVED_PEBS[1]
2. WL_RESERVED_PEBS[1]
3. UBI_LAYOUT_VOLUME_EBS[2]
4. MIN_FASTMAP_RESERVED_PEBS[2]
When all ubi volumes take all their PEBs, there are 3 (EBA_RESERVED_PEBS +
WL_RESERVED_PEBS + MIN_FASTMAP_RESERVED_PEBS - MIN_FASTMAP_TAKEN_PEBS[1])
free PEBs. Since commit f9c34bb529 ("ubi: Fix producing anchor PEBs")
and commit 4b68bf9a69 ("ubi: Select fastmap anchor PEBs considering
wear level rules") applied, there is only 1 (3 - FASTMAP_ANCHOR_PEBS[1] -
FASTMAP_NEXT_ANCHOR_PEBS[1]) free PEB to fill pool and wl_pool, after
filling pool, wl_pool is always empty. So, UBI could be stuck in an
infinite loop:
ubi_thread system_wq
wear_leveling_worker <--------------------------------------------------
get_peb_for_wl |
// fm_wl_pool, used = size = 0 |
schedule_work(&ubi->fm_work) |
|
update_fastmap_work_fn |
ubi_update_fastmap |
ubi_refill_pools |
// ubi->free_count - ubi->beb_rsvd_pebs < 5 |
// wl_pool is not filled with any PEBs |
schedule_erase(old_fm_anchor) |
ubi_ensure_anchor_pebs |
__schedule_ubi_work(wear_leveling_worker) |
|
__erase_worker |
ensure_wear_leveling |
__schedule_ubi_work(wear_leveling_worker) --------------------------
, which cause high cpu usage of ubi_bgt:
top - 12:10:42 up 5 min, 2 users, load average: 1.76, 0.68, 0.27
Tasks: 123 total, 3 running, 54 sleeping, 0 stopped, 0 zombie
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1589 root 20 0 0 0 0 R 45.0 0.0 0:38.86 ubi_bgt0d
319 root 20 0 0 0 0 I 15.2 0.0 0:15.29 kworker/0:3-eve
371 root 20 0 0 0 0 I 14.9 0.0 0:12.85 kworker/3:3-eve
20 root 20 0 0 0 0 I 11.3 0.0 0:05.33 kworker/1:0-eve
202 root 20 0 0 0 0 I 11.3 0.0 0:04.93 kworker/2:3-eve
In commit 4b68bf9a69 ("ubi: Select fastmap anchor PEBs considering
wear level rules"), there are three key changes:
1) Choose the fastmap anchor when the most free PEBs are available.
2) Enable anchor move within the anchor area again as it is useful
for distributing wear.
3) Import a candidate fm anchor and check this PEB's erase count during
wear leveling. If the wear leveling limit is exceeded, use the used
anchor area PEB with the lowest erase count to replace it.
The anchor candidate can be removed, we can check fm_anchor PEB's erase
count during wear leveling. Fix it by:
1) Removing 'fm_next_anchor' and check 'fm_anchor' during wear leveling.
2) Preferentially filling one free peb into fm_wl_pool in condition of
ubi->free_count > ubi->beb_rsvd_pebs, then try to reserve enough
free count for fastmap non anchor pebs after the above prerequisites
are met.
Then, there are at least 1 PEB in pool and 1 PEB in wl_pool after calling
ubi_refill_pools() with all erase works done.
Fetch a reproducer in [Link].
Fixes: 4b68bf9a69 ("ubi: Select fastmap anchor PEBs ... rules")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215407
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
This fixes the following sparse warnings:
fs/ubifs/xattr.c:680:58: warning: Using plain integer as NULL pointer
Signed-off-by: Haowen Bai <baihaowen@meizu.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Use kzalloc rather than duplicating its implementation, which
makes code simple and easy to understand.
Signed-off-by: Haowen Bai <baihaowen@meizu.com>
[rw: Fixed printk string]
Signed-off-by: Richard Weinberger <richard@nod.at>
The kernel test robot found this inconsistency:
>> drivers/soc/ixp4xx/ixp4xx-npe.c:737:34: warning:
'ixp4xx_npe_of_match' defined but not used [-Wunused-const-variable=]
737 | static const struct of_device_id ixp4xx_npe_of_match[] = {
This is because the match is enclosed in the of_match_ptr()
which compiles into NULL when OF is disabled and this
is unnecessary.
Fix it by dropping of_match_ptr() around the match.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20220523085520.913217-1-linus.walleij@linaro.org'
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
The Kontron KSwitch D10 is based on a Microchip LAN9668 SoC. It is a
managed ethernet network switch with either 8 copper ports or 6 copper
ports and 2 SFP cages.
Enable all required kconfig symbols, either as module where possible or
compiled-in where it is not possible.
Signed-off-by: Michael Walle <michael@walle.cc>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Link: https://lore.kernel.org/r/20220518141542.531148-1-michael@walle.cc'
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
AT91 DT #2 for 5.19:
- at91: more DT compliance updates for RTC and RTT nodes
- at91: sama7g5: add microphone support
* tag 'at91-dt-5.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/at91/linux:
ARM: dts: at91: sama7g5ek: add node for PDMC0
ARM: dts: at91: sama7g5: add nodes for PDMC
ARM: dts: at91: Use the generic "rtc" node name for the rtt IPs
ARM: dts: at91: Add the required 'atmel, rtt-rtc-time-reg' property
Link: https://lore.kernel.org/r/20220517153252.92393-1-nicolas.ferre@microchip.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Avoid return freed memory addresses,Modified to the actual error
return value of clk_register().
Fixes: 9645ccc7bd ("ep93xx: clock: convert in-place to COMMON_CLK")
Signed-off-by: Genjian Zhang <zhanggenjian@kylinos.cn>
Acked-by: Alexander Sverdlin <alexander.sverdlin@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Patch series from Nick Hawkins:
"The GXP is the HPE BMC SoC that is used in the majority of HPE current
generation servers. Traditionally the asic will last multiple
generations of server before being replaced.
Info about SoC:
HPE GXP is the name of the HPE Soc. This SoC is used to implement many
BMC features at HPE. It supports ARMv7 architecture based on the Cortex
A9 core. It is capable of using an AXI bus to which a memory controller
is attached. It has multiple SPI interfaces to connect boot flash and
BIOS flash. It uses a 10/100/1000 MAC for network connectivity. It has
multiple i2c engines to drive connectivity with a host infrastructure.
The initial patches enable the watchdog and timer enabling the host to
be able to boot."
* hpe/gxp-soc:
MAINTAINERS: Introduce HPE GXP Architecture
ARM: dts: Introduce HPE GXP Device tree
dt-bindings: arm: hpe: add GXP Support
dt-bindings: timer: hpe,gxp-timer: Add HPE GXP Timer and Watchdog
clocksource/drivers/timer-gxp: Add HPE GXP Timer
watchdog: hpe-wdt: Introduce HPE GXP Watchdog
ARM: configs: multi_v7_defconfig: Add HPE GXP ARCH
ARM: hpe: Introduce the HPE GXP architecture
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Historically we did distinguish between a flag that surpressed partition
scanning, and a combinations of the minors variable and another flag if
any partitions were supported. This was generally confusing and doesn't
make much sense, but some corner case uses of the loop driver actually
do want to support manually added partitions on a device that does not
actively scan for partitions. To make things worsee the loop driver
also wants to dynamically toggle the scanning for partitions on a live
gendisk, which makes the disk->flags updates non-atomic.
Introduce a new GD_SUPPRESS_PART_SCAN bit in disk->state that disables
just scanning for partitions, and toggle that instead of GENHD_FL_NO_PART
in the loop driver.
Fixes: 1ebe2e5f9d ("block: remove GENHD_FL_EXT_DEVT")
Reported-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20220527055806.1972352-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
paca.h uses ____cacheline_aligned without directly including cache.h,
where it's defined.
For Book3S builds that's OK because paca.h includes lppaca.h, and it
does include cache.h.
But Book3E builds have been getting cache.h indirectly via printk.h,
which is dicey, and in fact that include was recently removed, leading
to build errors such as:
ld: fs/isofs/dir.o:(.bss+0x0): multiple definition of `____cacheline_aligned'; fs/isofs/namei.o:(.bss+0x0): first defined here
So include cache.h directly to fix the build error.
Fixes: 534aa1dc97 ("printk: stop including cache.h from printk.h")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Add support for Telit LN910Cx 0x1250 composition
0x1250: rmnet, tty, tty, tty, tty
Signed-off-by: Carlo Lobrano <c.lobrano@gmail.com>
Acked-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix the MDIO interface declarations to reflect what is currently supported by
the PCI11010 / PCI11414 devices (C22 for RGMII and C22_C45 for SGMII)
Signed-off-by: Raju Lakkaraju <Raju.Lakkaraju@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This reverts commit 938ba4084a.
The wait queue @log_wait never has exclusive waiters, so there
is no need to use wake_up_interruptible_all(). Using
wake_up_interruptible() was the correct function to wake all
waiters.
Since there are no exclusive waiters, erroneously changing
wake_up_interruptible() to wake_up_interruptible_all() did not
result in any behavior change. However, using
wake_up_interruptible_all() on a wait queue without exclusive
waiters is fundamentally wrong.
Go back to using wake_up_interruptible() to wake all waiters.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220526203056.81123-1-john.ogness@linutronix.de
