nlmsg_flags are full of historical baggage, inconsistencies and
strangeness. Try to document it more thoroughly. Explain the meaning
of the ECHO flag (and while at it clarify the comment in the uAPI).
Handwave a little about the NEW request flags and how they make
sense on the surface but cater to really old paradigm before commands
were a thing.
I will add more notes on how to make use of ECHO and discouragement
for reuse of flags to the kernel-side documentation.
Link: https://lore.kernel.org/r/20220927212306.823862-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Rewrite clk-asm9260 to use parent index to use the reference clock.
During this rework two helpers are added:
- clk_hw_register_mux_table_parent_data() to supplement
clk_hw_register_mux_table() but using parent_data instead of
parent_names
- clk_hw_register_fixed_rate_parent_accuracy() to be used instead of
directly calling __clk_hw_register_fixed_rate(). The later function is
an internal API, which is better not to be called directly.
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20220916061740.87167-2-dmitry.baryshkov@linaro.org
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
The platform device is not released when platform_device_add_data()
fails. And platform_device_put() perfom one more pointer check than
put_device() to check for errors in the 'pdev' pointer.
Use platform_device_put() to release platform device in
platform_device_add()/platform_device_add_data()/
platform_device_add_resources() error case.
Fixes: c01044cc81 ("ACPI: HMAT: refactor hmat_register_target_device to hmem_register_device")
Signed-off-by: Lin Yujun <linyujun809@huawei.com>
Link: https://lore.kernel.org/r/20220914033755.99924-1-linyujun809@huawei.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
A lot of clean up work, as well as new drivers and new functions
- New clock drivers for MediaTek Helio X10 MT6795
- Add missing DPI1_HDMI clock in MT8195 VDOSYS1
- Clock driver changes to support GPU DVFS on MT8183, MT8192, MT8195
- Fix GPU clock topology on MT8195
- Propogate rate changes from GPU clock gate up the tree
- Clock mux notifiers for GPU-related PLLs
- Conversion of more "simple" drivers to mtk_clk_simple_probe()
- Hook up mtk_clk_simple_remove() for "simple" MT8192 clock drivers
- Fixes to previous |struct clk| to |struct clk_hw| conversion
- Shrink MT8192 clock driver by deduplicating clock parent lists
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Merge tag 'mtk-clk-for-6.1' of https://git.kernel.org/pub/scm/linux/kernel/git/wens/linux into clk-mtk
Pull MediaTek clk driver updates from Chen-Yu Tsai:
A lot of clean up work, as well as new drivers and new functions
- New clock drivers for MediaTek Helio X10 MT6795
- Add missing DPI1_HDMI clock in MT8195 VDOSYS1
- Clock driver changes to support GPU DVFS on MT8183, MT8192, MT8195
- Fix GPU clock topology on MT8195
- Propogate rate changes from GPU clock gate up the tree
- Clock mux notifiers for GPU-related PLLs
- Conversion of more "simple" drivers to mtk_clk_simple_probe()
- Hook up mtk_clk_simple_remove() for "simple" MT8192 clock drivers
- Fixes to previous |struct clk| to |struct clk_hw| conversion
- Shrink MT8192 clock driver by deduplicating clock parent lists
* tag 'mtk-clk-for-6.1' of https://git.kernel.org/pub/scm/linux/kernel/git/wens/linux: (31 commits)
clk: mediatek: mt8192: deduplicate parent clock lists
clk: mediatek: Migrate remaining clk_unregister_*() to clk_hw_unregister_*()
clk: mediatek: fix unregister function in mtk_clk_register_dividers cleanup
clk: mediatek: clk-mt8192: Add clock mux notifier for mfg_pll_sel
clk: mediatek: clk-mt8192-mfg: Propagate rate changes to parent
clk: mediatek: clk-mt8195-topckgen: Drop univplls from mfg mux parents
clk: mediatek: clk-mt8195-topckgen: Add GPU clock mux notifier
clk: mediatek: clk-mt8195-topckgen: Register mfg_ck_fast_ref as generic mux
clk: mediatek: clk-mt8195-mfg: Reparent mfg_bg3d and propagate rate changes
clk: mediatek: mt8183: Add clk mux notifier for MFG mux
clk: mediatek: mux: add clk notifier functions
clk: mediatek: mt8183: mfgcfg: Propagate rate changes to parent
clk: mediatek: Use mtk_clk_register_gates_with_dev in simple probe
clk: mediatek: gate: Export mtk_clk_register_gates_with_dev
clk: mediatek: add VDOSYS1 clock
dt-bindings: clk: mediatek: Add MT8195 DPI clocks
clk: mediatek: mt8192: add mtk_clk_simple_remove
clk: mediatek: mt8183: use mtk_clk_simple_probe to simplify driver
clk: mediatek: mt6797: use mtk_clk_simple_probe to simplify driver
clk: mediatek: mt6779: use mtk_clk_simple_probe to simplify driver
...
ida_alloc_max() makes it clear that the second argument is inclusive,
and the alloc/free terminology is more idiomatic and symmetric then
get/remove.
Signed-off-by: Bo Liu <liubo03@inspur.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/20220926012635.3205-1-liubo03@inspur.com
[djbw: reword changelog]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
The alignment constraint for namespace creation in a region was
increased, from 2M to 16M, for non-PowerPC architectures in v5.7 with
commit 2522afb86a ("libnvdimm/region: Introduce an 'align'
attribute"). The thought behind the change was that region alignment
should be uniform across all architectures and, since PowerPC had the
largest alignment constraint of 16M, all architectures should conform to
that alignment.
The change regressed namespace creation in pre-defined regions that
relied on 2M alignment but a workaround was provided in the form of a
sysfs attribute, named 'align', that could be adjusted to a non-default
alignment value.
However, the sysfs attribute's store function returned an error (-ENXIO)
when userspace attempted to change the alignment of a region that had no
mappings. This affected 2M aligned regions of volatile memory that were
defined in a device tree using "pmem-region" and created by the
of_pmem_region_driver, since those regions do not contain mappings
(ndr_mappings is 0).
Allow userspace to set the align attribute on pre-existing regions that
do not have mappings so that namespaces can still be within those
regions, despite not being aligned to 16M.
Link: https://lore.kernel.org/lkml/CA+CK2bDJ3hrWoE91L2wpAk+Yu0_=GtYw=4gLDDD7mxs321b_aA@mail.gmail.com
Fixes: 2522afb86a ("libnvdimm/region: Introduce an 'align' attribute")
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Link: https://lore.kernel.org/r/20220830054505.1159488-1-tyhicks@linux.microsoft.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
The part of the media and blitter engine contexts that we care about for
setting up an initial state on MTL are nearly similar to DG2 (and PVC).
The difference being PRT_BB_STATE being replaced with NOP.
For render/compute engines, the part of the context images are nearly
the same, although the layout had a very slight change --- one POSH
register was removed and the placement of some LRI/noops adjusted
slightly to compensate.
v2:
- Dg2, mtl xcs offsets slightly vary. Use a separate offsets array(Bala)
- Add missing nop in xcs offsets(Bala)
v3:
- Fix the spacing for nop in xcs offset(MattR)
v4:
- Fix rcs register offset(MattR)
v4.1:
- Fix commit message(Lucas)
Bspec: 46261, 46260, 45585
Cc: Balasubramani Vivekanandan <balasubramani.vivekanandan@intel.com>
Cc: Licas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220928155511.2379663-1-radhakrishna.sripada@intel.com
9178e3dcb121 ("mm: discard __GFP_ATOMIC") removed __GFP_ATOMIC,
replacing it with a check for not __GFP_DIRECT_RECLAIM.
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Rob Clark <robdclark@chromium.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Signed-off-by: Dave Airlie <airlied@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220929161404.2769414-1-robdclark@gmail.com
Clean up config files by:
- removing configs that were deleted in the past
- removing configs not in tree and without recently pending patches
- adding new configs that are replacements for old configs in the file
For some detailed information, see Link.
Link: https://lore.kernel.org/kernel-janitors/20220929090645.1389-1-lukas.bulwahn@gmail.com/
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>
Commit 4acb83417c ("sbitmap: fix batched wait_cnt accounting")
is a big improvement: without it, I had to revert to before commit
040b83fcec ("sbitmap: fix possible io hung due to lost wakeup")
to avoid the high system time and freezes which that had introduced.
Now okay on the NVME laptop, but 4acb83417c is a disaster for heavy
swapping (kernel builds in low memory) on another: soon locking up in
sbitmap_queue_wake_up() (into which __sbq_wake_up() is inlined), cycling
around with waitqueue_active() but wait_cnt 0 . Here is a backtrace,
showing the common pattern of outer sbitmap_queue_wake_up() interrupted
before setting wait_cnt 0 back to wake_batch (in some cases other CPUs
are idle, in other cases they're spinning for a lock in dd_bio_merge()):
sbitmap_queue_wake_up < sbitmap_queue_clear < blk_mq_put_tag <
__blk_mq_free_request < blk_mq_free_request < __blk_mq_end_request <
scsi_end_request < scsi_io_completion < scsi_finish_command <
scsi_complete < blk_complete_reqs < blk_done_softirq < __do_softirq <
__irq_exit_rcu < irq_exit_rcu < common_interrupt < asm_common_interrupt <
_raw_spin_unlock_irqrestore < __wake_up_common_lock < __wake_up <
sbitmap_queue_wake_up < sbitmap_queue_clear < blk_mq_put_tag <
__blk_mq_free_request < blk_mq_free_request < dd_bio_merge <
blk_mq_sched_bio_merge < blk_mq_attempt_bio_merge < blk_mq_submit_bio <
__submit_bio < submit_bio_noacct_nocheck < submit_bio_noacct <
submit_bio < __swap_writepage < swap_writepage < pageout <
shrink_folio_list < evict_folios < lru_gen_shrink_lruvec <
shrink_lruvec < shrink_node < do_try_to_free_pages < try_to_free_pages <
__alloc_pages_slowpath < __alloc_pages < folio_alloc < vma_alloc_folio <
do_anonymous_page < __handle_mm_fault < handle_mm_fault <
do_user_addr_fault < exc_page_fault < asm_exc_page_fault
See how the process-context sbitmap_queue_wake_up() has been interrupted,
after bringing wait_cnt down to 0 (and in this example, after doing its
wakeups), before advancing wake_index and refilling wake_cnt: an
interrupt-context sbitmap_queue_wake_up() of the same sbq gets stuck.
I have almost no grasp of all the possible sbitmap races, and their
consequences: but __sbq_wake_up() can do nothing useful while wait_cnt 0,
so it is better if sbq_wake_ptr() skips on to the next ws in that case:
which fixes the lockup and shows no adverse consequence for me.
The check for wait_cnt being 0 is obviously racy, and ultimately can lead
to lost wakeups: for example, when there is only a single waitqueue with
waiters. However, lost wakeups are unlikely to matter in these cases,
and a proper fix requires redesign (and benchmarking) of the batched
wakeup code: so let's plug the hole with this bandaid for now.
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Link: https://lore.kernel.org/r/9c2038a7-cdc5-5ee-854c-fbc6168bf16@google.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
With commit 987f20a9dc ("a.out: Remove the a.out implementation"), the
use of the special taso flag for alpha architectures in the linux_binprm
struct is gone.
Remove the definition of taso in the linux_binprm struct.
No functional change.
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220929203903.9475-1-lukas.bulwahn@gmail.com
After commit bba04d965d06("of/fdt: remove unused of_scan_flat_dt_by_path"), no
one use struct fdt_scan_status, so remove it.
Signed-off-by: Yuan Can <yuancan@huawei.com>
Reviewed-by: Frank Rowand <frank.rowand@sony.com>
Link: https://lore.kernel.org/r/20220927133739.98493-1-yuancan@huawei.com
Signed-off-by: Rob Herring <robh@kernel.org>
Handle 'data-lanes' property of the DSI output endpoint, it is possible
to describe DSI link with 1 or 2 data lanes this way.
Signed-off-by: Marek Vasut <marex@denx.de>
Link: https://lore.kernel.org/r/20220926234501.583115-1-marex@denx.de
Signed-off-by: Rob Herring <robh@kernel.org>
This isn't a reliable mechanism to tell if we have task_work pending, we
really should be looking at whether we have any items queued. This is
problematic if forward progress is gated on running said task_work. One
such example is reading from a pipe, where the write side has been closed
right before the read is started. The fput() of the file queues TWA_RESUME
task_work, and we need that task_work to be run before ->release() is
called for the pipe. If ->release() isn't called, then the read will sit
forever waiting on data that will never arise.
Fix this by io_run_task_work() so it checks if we have task_work pending
rather than rely on TIF_NOTIFY_SIGNAL for that. The latter obviously
doesn't work for task_work that is queued without TWA_SIGNAL.
Reported-by: Christiano Haesbaert <haesbaert@haesbaert.org>
Cc: stable@vger.kernel.org
Link: https://github.com/axboe/liburing/issues/665
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Merge tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull coredump fix from Al Viro:
"Fix for breakage in dump_user_range()"
* tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
[coredump] don't use __kernel_write() on kmap_local_page()
In the probe path, dev_err() can be replaced with dev_err_probe()
which will check if error code is -EPROBE_DEFER and prints the
error name. It also sets the defer probe reason which can be
checked later through debugfs.
Signed-off-by: Yuan Can <yuancan@huawei.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220929015503.17301-3-yuancan@huawei.com
This uses l2cap_chan_hold_unless_zero() after calling
__l2cap_get_chan_blah() to prevent the following trace:
Bluetooth: l2cap_core.c:static void l2cap_chan_destroy(struct kref
*kref)
Bluetooth: chan 0000000023c4974d
Bluetooth: parent 00000000ae861c08
==================================================================
BUG: KASAN: use-after-free in __mutex_waiter_is_first
kernel/locking/mutex.c:191 [inline]
BUG: KASAN: use-after-free in __mutex_lock_common
kernel/locking/mutex.c:671 [inline]
BUG: KASAN: use-after-free in __mutex_lock+0x278/0x400
kernel/locking/mutex.c:729
Read of size 8 at addr ffff888006a49b08 by task kworker/u3:2/389
Link: https://lore.kernel.org/lkml/20220622082716.478486-1-lee.jones@linaro.org
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Sungwoo Kim <iam@sung-woo.kim>
When possible at compile-time, make use of smaller types in
prandom_u32_max(), so that we can use smaller batches from random.c,
which in turn leads to a 2x or 4x performance boost. This makes a
difference, for example, in kfence, which needs a fast stream of small
numbers (booleans).
At the same time, we use the occasion to update the old documentation on
these functions. prandom_u32() and prandom_bytes() have direct
replacements now in random.h, while prandom_u32_max() remains useful as
a prandom.h function, since it's not cryptographically secure by virtue
of not being evenly distributed.
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Acked-by: Marco Elver <elver@google.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
There are numerous places in the kernel that would be sped up by having
smaller batches. Currently those callsites do `get_random_u32() & 0xff`
or similar. Since these are pretty spread out, and will require patches
to multiple different trees, let's get ahead of the curve and lay the
foundation for `get_random_u8()` and `get_random_u16()`, so that it's
then possible to start submitting conversion patches leisurely.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
On some small machines with little entropy, a quasi-unique hostname is
sometimes a relevant factor. I've seen, for example, 8 character
alpha-numeric serial numbers. In addition, the time at which the hostname
is set is usually a decent measurement of how long early boot took. So,
call add_device_randomness() on new hostnames, which feeds its arguments
to the RNG in addition to a fresh cycle counter.
Low cost hooks like this never hurt and can only ever help, and since
this costs basically nothing for an operation that is never a fast path,
this is an overall easy win.
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Rather than going through the current-> indirection for utsname, at this
point in boot, init_utsname()==utsname(), so just use it directly that
way. Additionally, init_utsname() appears to be available nearly always,
so move it into random_init_early().
Suggested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
As of the prior commit, the RNG will have incorporated both a cycle
counter value and RDRAND, in addition to various other environmental
noise. Therefore, using get_random_u32() will supply a stronger seed
than simply using random_get_entropy(). N.B.: random_get_entropy()
should be considered an internal API of random.c and not generally
consumed.
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Marco Elver <elver@google.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
The full RNG initialization relies on some timestamps, made possible
with initialization functions like time_init() and timekeeping_init().
However, these are only available rather late in initialization.
Meanwhile, other things, such as memory allocator functions, make use of
the RNG much earlier.
So split RNG initialization into two phases. We can provide arch
randomness very early on, and then later, after timekeeping and such are
available, initialize the rest.
This ensures that, for example, slabs are properly randomized if RDRAND
is available. Without this, CONFIG_SLAB_FREELIST_RANDOM=y loses a degree
of its security, because its random seed is potentially deterministic,
since it hasn't yet incorporated RDRAND. It also makes it possible to
use a better seed in kfence, which currently relies on only the cycle
counter.
Another positive consequence is that on systems with RDRAND, running
with CONFIG_WARN_ALL_UNSEEDED_RANDOM=y results in no warnings at all.
One subtle side effect of this change is that on systems with no RDRAND,
RDTSC is now only queried by random_init() once, committing the moment
of the function call, instead of multiple times as before. This is
intentional, as the multiple RDTSCs in a loop before weren't
accomplishing very much, with jitter being better provided by
try_to_generate_entropy(). Plus, filling blocks with RDTSC is still
being done in extract_entropy(), which is necessarily called before
random bytes are served anyway.
Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
PCIe r6.0, sec 5.9, requires a 10ms delay between programming a device to
change to or from D3hot and the time the device is next accessed (unless
Readiness Notifications are used).
The 10ms value (PCI_PM_D3HOT_WAIT) doesn't appear directly here because
some chipsets require 120ms for devices *below* them (pci_pm_d3hot_delay)
and some devices require more or less than 10ms (dev->d3hot_delay).
But msleep(10) typically waits about *20*ms, which is more than we need.
Switch to usleep_range() to improve the delay accuracy.
Based on a commit from Sajid in the Pixel 6 kernel tree [1]. On a Pixel 6,
the 10ms delay for the Exynos PCIe device delayed for an average of 19ms.
Switching to usleep_range() decreased the resume time by about 9ms.
[1] https://android.googlesource.com/kernel/gs/+/18a8cad68d8e6d50f339a716a18295e6d987cee3
[bhelgaas commit log, add timers-howto.rst link]
Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/timers/timers-howto.rst?id=v5.19#n73
Link: https://lore.kernel.org/r/20220921212735.2131588-1-willmcvicker@google.com
Signed-off-by: Sajid Dalvi <sdalvi@google.com>
Signed-off-by: Will McVicker <willmcvicker@google.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
checkpatch does not point out that VM_BUG_ON() and friends should be
avoided, however, Linus notes:
VM_BUG_ON() has the exact same semantics as BUG_ON. It is literally
no different, the only difference is "we can make the code smaller
because these are less important". [1]
So let's warn on VM_BUG_ON() and other BUG variants as well. While at it,
make it clearer that the kernel really shouldn't be crashed.
As there are some subsystem BUG macros that actually don't end up crashing
the kernel -- for example, KVM_BUG_ON() -- exclude these manually.
[1] https://lore.kernel.org/r/CAHk-=wg40EAZofO16Eviaj7mfqDhZ2gVEbvfsMf6gYzspRjYvw@mail.gmail.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20220923113426.52871-3-david@redhat.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Linus notes [1] that the introduction of new code that uses VM_BUG_ON()
is just as bad as BUG_ON(), because it will crash the kernel on
distributions that enable CONFIG_DEBUG_VM (like Fedora):
VM_BUG_ON() has the exact same semantics as BUG_ON. It is literally
no different, the only difference is "we can make the code smaller
because these are less important". [2]
This resulted in a more generic discussion about usage of BUG() and
friends. While there might be corner cases that still deserve a BUG_ON(),
most BUG_ON() cases should simply use WARN_ON_ONCE() and implement a
recovery path if reasonable:
The only possible case where BUG_ON can validly be used is "I have
some fundamental data corruption and cannot possibly return an
error". [2]
As a very good approximation is the general rule:
"absolutely no new BUG_ON() calls _ever_" [2]
... not even if something really shouldn't ever happen and is merely for
documenting that an invariant always has to hold. However, there are sill
exceptions where BUG_ON() may be used:
If you have a "this is major internal corruption, there's no way we can
continue", then BUG_ON() is appropriate. [3]
There is only one good BUG_ON():
Now, that said, there is one very valid sub-form of BUG_ON():
BUILD_BUG_ON() is absolutely 100% fine. [2]
While WARN will also crash the machine with panic_on_warn set, that's
exactly to be expected:
So we have two very different cases: the "virtual machine with good
logging where a dead machine is fine" - use 'panic_on_warn'. And
the actual real hardware with real drivers, running real loads by
users. [4]
The basic idea is that warnings will similarly get reported by users
and be found during testing. However, in contrast to a BUG(), there is a
way to actually influence the expected behavior (e.g., panic_on_warn)
and to eventually keep the machine alive to extract some debug info.
Ingo notes that not all WARN_ON_ONCE cases need recovery. If we don't ever
expect this code to trigger in any case, recovery code is not really
helpful.
I'd prefer to keep all these warnings 'simple' - i.e. no attempted
recovery & control flow, unless we ever expect these to trigger.
[5]
There have been different rules floating around that were never properly
documented. Let's try to clarify.
[1] https://lkml.kernel.org/r/CAHk-=wiEAH+ojSpAgx_Ep=NKPWHU8AdO3V56BXcCsU97oYJ1EA@mail.gmail.com
[2] https://lore.kernel.org/r/CAHk-=wg40EAZofO16Eviaj7mfqDhZ2gVEbvfsMf6gYzspRjYvw@mail.gmail.com
[3] https://lkml.kernel.org/r/CAHk-=wit-DmhMfQErY29JSPjFgebx_Ld+pnerc4J2Ag990WwAA@mail.gmail.com
[4] https://lore.kernel.org/r/CAHk-=wgF7K2gSSpy=m_=K3Nov4zaceUX9puQf1TjkTJLA2XC_g@mail.gmail.com
[5] https://lore.kernel.org/r/YwIW+mVeZoTOxn%2F4@gmail.com
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20220923113426.52871-2-david@redhat.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Since commit b3ac04132c ("mm/rmap: Turn page_referenced() into
folio_referenced()") the page_referenced function name was modified,
so fix it up to use the correct one.
Signed-off-by: Vernon Yang <vernon2gm@gmail.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Link: https://lore.kernel.org/r/20220926152032.74621-1-vernon2gm@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
The Code of Conduct interpretation does not reflect the current
practices of the CoC committee or the TAB. Update the documentation
to remove references to initial committees and boot strap periods
since it is past that time, and note that the this document
does serve as the documentation for the CoC committee processes.
Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20220926211149.2278214-1-kristen@linux.intel.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Now that building html docs with math expressions does not need texlive
packages, remove the note on the requirement in the "Sphinx Install"
section.
Instead, add sections of "Math Expressions in HTML" and "Choice of Math
Renderer".
Describe the effect of setting SPHINX_IMGMATH in the latter section.
Signed-off-by: Akira Yokosawa <akiyks@gmail.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/a67e3279-6bc7-ee2c-2b49-9275252460b0@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Bring the description on when to use the Reported-by: tag found in
Documentation/process/5.Posting.rst more in line with the description in
Documentation/process/submitting-patches.rst: before this change the two
were contradicting each other, as the latter is way more permissive and
only states '[...] if the bug was reported in private, then ask for
permission first before using the Reported-by tag.'
Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Link: https://lore.kernel.org/r/2fc7162dfb76e04da5ea903c9c170d913e735dad.1664372256.git.linux@leemhuis.info
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
After commit 22471e1313 ("kconfig: use a menu in arch/Kconfig to reduce
clutter"), the location of Kprobes is under "General architecture-dependent
options" rather than "General setup".
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Fixes: 22471e1313 ("kconfig: use a menu in arch/Kconfig to reduce clutter")
Link: https://lore.kernel.org/r/1663322106-12178-1-git-send-email-yangtiezhu@loongson.cn
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
A brown paper bag where -Wno-error=deprecated-declarations was added
from compiler output when the right thing is to add
-Wno-deprecated-declarations, fix it.
Fixes: 4ee3c4da8b ("perf scripting python: Do not build fail on deprecation warnings")
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
On K3 SoCs, the power-domains property is needed. On the earlier SoCs,
the power-domains property is handled by the interconnect target module
parent device.
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: Keerthy <j-keerthy@ti.com>
Cc: Nishanth Menon <nm@ti.com>
Cc: Vignesh Raghavendra <vigneshr@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20220919112357.64997-1-tony@atomide.com
Signed-off-by: Rob Herring <robh@kernel.org>
The top-level index.rst file is the entry point for the kernel's
documentation, especially for readers of the HTML output. It is currently
a mess containing everything we thought to throw in there. Firefox says it
would require 26 pages of paper to print it. That is not a user-friendly
introduction.
This series aims to improve our documentation entry point with a focus on
rewriting index.rst. The result is, IMO, simpler and more approachable.
For anybody who wants to see the rendered results without building the
docs, have a look at:
https://static.lwn.net/kerneldoc/
This time around I've rendered the pages using the "Read The Docs" theme,
since that's what everybody will get by default. That theme ignores the
directives regarding the left column, so the results are not as good there.
I have a series proposing a default-theme change in the works, but that's a
separate topic.
This is only a beginning; I think this kind of organizational effort has to
be pushed down into the lower layers of the docs tree itself. But one has
to start somewhere.
