Hector Martin 4fffd776f5 locking/atomic: Make test_and_*_bit() ordered on failure ... commit 415d832497 upstream. These operations are documented as always ordered in include/asm-generic/bitops/instrumented-atomic.h, and producer-consumer type use cases where one side needs to ensure a flag is left pending after some shared data was updated rely on this ordering, even in the failure case. This is the case with the workqueue code, which currently suffers from a reproducible ordering violation on Apple M1 platforms (which are notoriously out-of-order) that ends up causing the TTY layer to fail to deliver data to userspace properly under the right conditions. This change fixes that bug. Change the documentation to restrict the "no order on failure" story to the _lock() variant (for which it makes sense), and remove the early-exit from the generic implementation, which is what causes the missing barrier semantics in that case. Without this, the remaining atomic op is fully ordered (including on ARM64 LSE, as of recent versions of the architecture spec). Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: stable@vger.kernel.org Fixes: e986a0d6cb ("locking/atomics, asm-generic/bitops/atomic.h: Rewrite using atomic_*() APIs") Fixes: 61e02392d3 ("locking/atomic/bitops: Document and clarify ordering semantics for failed test_and_{}_bit()") Signed-off-by: Hector Martin <marcan@marcan.st> Acked-by: Will Deacon <will@kernel.org> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2022-08-25 11:15:42 +02:00
..
ABI	iio: adc: vf610: fix conversion mode sysfs node name	2022-07-02 16:27:34 +02:00
accelerators	ocxl: Document new OCXL IOCTLs	2018-06-03 20:40:33 +10:00
accounting
acpi	ACPI: property: graph: Update graph documentation to use generic references	2018-07-23 12:44:52 +02:00
admin-guide	x86/speculation: Add RSB VM Exit protections	2022-08-11 12:48:41 +02:00
aoe
arm	ARM: 8833/1: Ensure that NEON code always compiles with Clang	2019-04-05 22:33:08 +02:00
arm64	arm64: errata: Hide CTR_EL0.DIC on systems affected by Neoverse-N1 #1542419	2020-04-29 16:31:08 +02:00
auxdisplay
backlight
block	block: Track DISCARD statistics and output them in stat and diskstat	2018-07-18 08:44:22 -06:00
blockdev	zram: introduce zram memory tracking	2018-06-07 17:34:34 -07:00
bpf	Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next	2018-08-07 11:02:05 -07:00
bus-devices
cdrom
cgroup-v1
cma
connector
console	Documentation: corrections to console/console.txt	2018-08-10 16:09:40 -06:00
core-api	idr: Change documentation license	2018-10-15 16:31:29 -04:00
cpu-freq
cpuidle
crypto	crypto: remove redundant type flags from tfm allocation	2018-07-09 00:30:29 +08:00
dev-tools	doc: dev-tools: kselftest.rst: update contributing new tests	2018-06-29 09:01:50 -06:00
device-mapper	dm integrity: conditionally disable "recalculate" feature	2021-01-30 13:32:13 +01:00
devicetree	dt-bindings: gpio: altera: correct interrupt-cells	2022-06-14 16:59:30 +02:00
doc-guide	Documentation/sphinx: allow "functions" with no parameters	2018-06-30 07:52:42 -06:00
driver-api	ata: make qc_prep return ata_completion_errors	2020-10-01 13:14:54 +02:00
driver-model	dmaengine: add a new helper dmaenginem_async_device_register	2018-07-30 10:50:22 +05:30
early-userspace	initramfs: move gen_initramfs_list.sh from scripts/ to usr/	2018-08-22 23:21:44 +09:00
EDID
extcon
fault-injection
fb	uvesafb: Fix URLs in the documentation	2018-09-26 18:11:23 +02:00
features	ARM: 8777/1: Hook up SYNC_CORE functionality for sys_membarrier()	2018-07-11 11:02:08 +01:00
filesystems	locks: print a warning when mount fails due to lack of "mand" support	2021-08-26 08:36:49 -04:00
firmware_class
fmc
fpga	docs: fpga: add a document for FPGA Device Feature List (DFL) Framework Overview	2018-07-15 13:55:44 +02:00
gpio
gpu	drm/msm/gpu: Add the buffer objects from the submit to the crash dump	2018-07-30 08:50:10 -04:00
hid	HID: doc: fix wrong data structure reference for UHID_OUTPUT	2019-12-05 09:20:36 +01:00
hwmon	Revert "hwmon: Make chip parameter for with_info API mandatory"	2022-06-25 11:49:18 +02:00
i2c	i2c: i801: Add support for Intel Comet Lake	2019-05-04 09:20:15 +02:00
ia64
ide
iio
infiniband
input	input: add MT_TOOL_DIAL	2018-07-17 15:33:47 +02:00
ioctl	Char/Misc driver patches for 4.19-rc1	2018-08-18 11:04:51 -07:00
isdn
kbuild	kbuild: support LLVM=1 to switch the default tools to Clang/LLVM	2020-09-26 18:01:32 +02:00
kdump
kernel-hacking	doc:it_IT: translation for kernel-hacking	2018-07-26 16:21:09 -06:00
laptops
leds
lightnvm
livepatch	livepatch: Remove not longer valid limitations from the documentation	2018-05-24 15:37:57 +02:00
locking	locking: Implement an algorithm choice for Wound-Wait mutexes	2018-07-03 09:44:36 +02:00
m68k
maintainer	docs: Fix more broken references	2018-06-15 18:11:26 -03:00
md
media	media: videodev2.h: RGB BT2020 and HSV are always full range	2020-11-05 11:08:40 +01:00
memory-devices
mic
mips
misc-devices	pci_endpoint_test: Add 2 ioctl commands	2018-07-19 11:46:57 +01:00
mmc
mtd
namespaces
netlabel
networking	Documentation: fix sctp_wmem in ip-sysctl.rst	2022-08-11 12:48:40 +02:00
nfc
nios2
nvdimm
nvmem
openrisc
parisc
PCI	Merge branch 'remotes/lorenzo/pci/dwc'	2018-08-15 14:59:11 -05:00
pcmcia	pcmcia: remove long deprecated pcmcia_request_exclusive_irq() function	2018-08-18 12:30:42 -07:00
perf
phy
platform
power	PM / reboot: Eliminate race between reboot and suspend	2018-08-06 12:35:20 +02:00
powerpc	powerpc: Document issues with TM on POWER9	2018-07-02 23:54:29 +10:00
pps
process	docs: submitting-patches: Fix crossref to 'The canonical patch format'	2022-06-06 08:24:22 +02:00
pti
ptp
rapidio
RCU	rculist: Improve documentation for list_for_each_entry_from_rcu()	2018-07-12 15:39:25 -07:00
riscv	perf: riscv: Add Document for Future Porting Guide	2018-06-04 14:02:11 -07:00
s390
scheduler	sched/fair: Fix low cpu usage with high throttling by removing expiration of cpu-local slices	2019-11-12 19:20:50 +01:00
scsi	scsi: documentation: add scsi_mod.use_blk_mq to scsi-parameters	2018-08-27 12:26:10 -04:00
security	Kbuild: rename CC_STACKPROTECTOR[_STRONG] config variables	2018-06-14 12:21:18 +09:00
serial
sh
sound	ALSA: hda/realtek - Remove now-unnecessary XPS 13 headphone noise fixups	2020-04-17 10:48:45 +02:00
sparc
sphinx	tweewide: Fix most Shebang lines	2021-05-22 10:59:50 +02:00
sphinx-static
spi
sysctl	random: fix sysctl documentation nits	2022-06-25 11:49:09 +02:00
target	tweewide: Fix most Shebang lines	2021-05-22 10:59:50 +02:00
thermal
timers	timekeeping.txt: Correct maxCount of n-bit binary counter	2018-07-23 09:33:06 -06:00
trace	tracing/histogram: Rename "cpu" to "common_cpu"	2021-08-12 13:19:42 +02:00
translations	This was a moderately busy cycle for docs, with the usual collection of	2018-08-14 14:29:31 -07:00
usb	USB: rio500: Remove Rio 500 kernel driver	2019-10-17 13:44:47 -07:00
userspace-api	Documentation: Add section about CPU vulnerabilities for Spectre	2019-07-14 08:11:17 +02:00
virtual	KVM: X86: MMU: Use the correct inherited permissions to get shadow page	2021-08-15 13:05:04 +02:00
vm	mm/slub: clarify verification reporting	2021-06-30 08:48:26 -04:00
w1	w1: fix w1_ds2438 documentation	2018-07-07 17:27:13 +02:00
watchdog
wimax
x86	x86/speculation/taa: Add documentation for TSX Async Abort	2019-11-12 19:21:34 +01:00
xtensa
.gitignore
00-INDEX
atomic_bitops.txt	locking/atomic: Make test_and_*_bit() ordered on failure	2022-08-25 11:15:42 +02:00
atomic_t.txt	x86/atomic: Fix smp_mb__{before,after}_atomic()	2019-07-26 09:14:08 +02:00
bt8xxgpio.txt
btmrvl.txt
bus-virt-phys-mapping.txt
Changes
clearing-warn-once.txt
CodingStyle
conf.py	docs/conf.py: Cope with removal of language=None in Sphinx 5.0.0	2022-06-14 16:59:30 +02:00
cpu-load.txt
cputopology.txt
crc32.txt
dcdbas.txt
debugging-modules.txt
debugging-via-ohci1394.txt
dell_rbu.txt
digsig.txt
DMA-API-HOWTO.txt
DMA-API.txt
DMA-attributes.txt	Reinstate some of "swiotlb: rework "fix info leak with DMA_FROM_DEVICE""	2022-05-25 09:10:41 +02:00
DMA-ISA-LPC.txt
docutils.conf
dontdiff
efi-stub.txt
eisa.txt
flexible-arrays.txt
futex-requeue-pi.txt
gcc-plugins.txt
highuid.txt
hw_random.txt
hwspinlock.txt
index.rst	x86/speculation/mds: Add mds_clear_cpu_buffers()	2019-05-14 19:17:54 +02:00
Intel-IOMMU.txt
intel_txt.txt
io-mapping.txt
io_ordering.txt
iostats.txt	block: Track DISCARD statistics and output them in stat and diskstat	2018-07-18 08:44:22 -06:00
IPMI.txt
IRQ-affinity.txt
IRQ-domain.txt
IRQ.txt
irqflags-tracing.txt
isa.txt
isapnp.txt
kernel-per-CPU-kthreads.txt
kobject.txt
kprobes.txt	kprobes/Documentation: Fix various typos	2018-06-22 11:10:55 +02:00
kref.txt
ldm.txt
lockup-watchdogs.txt
logo.gif
logo.txt
lsm.txt
lzo.txt
mailbox.txt
Makefile
memory-barriers.txt	sched/Documentation: Update wake_up() & co. memory-barrier guarantees	2018-07-17 09:30:34 +02:00
memory-hotplug.txt
men-chameleon-bus.txt
nommu-mmap.txt	Documentation: nommu-map: Fix duplicate word typo	2018-06-26 09:01:27 -06:00
ntb.txt
numastat.txt
padata.txt
parport-lowlevel.txt
percpu-rw-semaphore.txt
phy.txt
pi-futex.txt
pnp.txt
preempt-locking.txt
pwm.txt
rbtree.txt
remoteproc.txt
rfkill.txt	rfkill: Fix several typos in documentation	2018-06-15 13:36:08 +02:00
robust-futex-ABI.txt
robust-futexes.txt	futex: Update comments and docs about return values of arch futex code	2019-07-03 13:14:49 +02:00
rpmsg.txt
rtc.txt
SAK.txt
sgi-ioc4.txt
siphash.txt
SM501.txt
smsc_ece1099.txt
speculation.txt
static-keys.txt
SubmittingPatches
svga.txt
switchtec.txt
sync_file.txt
tee.txt
this_cpu_ops.txt
unaligned-memory-access.txt
vfio-mediated-device.txt	vfio/mdev: Check globally for duplicate devices	2018-06-08 10:24:27 -06:00
vfio.txt
video-output.txt
xillybus.txt
xz.txt
zorro.txt