linux/include/asm-generic
Hector Martin 415d832497 locking/atomic: Make test_and_*_bit() ordered on failure
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>
2022-08-16 09:19:43 -07:00
..
bitops locking/atomic: Make test_and_*_bit() ordered on failure 2022-08-16 09:19:43 -07:00
vdso lib/vdso: Avoid highres update if clocksource is not VDSO capable 2020-02-17 20:12:17 +01:00
access_ok.h uaccess: remove CONFIG_SET_FS 2022-02-25 09:36:06 +01:00
archrandom.h random: handle archrandom with multiple longs 2022-07-25 13:26:14 +02:00
asm-offsets.h
asm-prototypes.h
atomic64.h locking/atomic: delete !ARCH_ATOMIC remnants 2021-05-26 13:20:52 +02:00
atomic.h locking/atomic: delete !ARCH_ATOMIC remnants 2021-05-26 13:20:52 +02:00
audit_change_attr.h
audit_dir_write.h
audit_read.h
audit_signal.h
audit_write.h
barrier.h asm-generic: Add memory barrier dma_mb() 2022-06-23 18:34:58 +01:00
bitops.h include: move find.h from asm_generic to linux 2022-01-15 08:47:31 -08:00
bitsperlong.h lib: extend the scope of small_const_nbits() macro 2021-05-06 19:24:11 -07:00
bug.h bug: Have __warn() prototype defined unconditionally 2022-04-26 10:59:57 +02:00
bugs.h
cache.h
cacheflush.h Add linux/cacheflush.h 2021-11-17 10:36:15 -05:00
checksum.h unify generic instances of csum_partial_copy_nocheck() 2020-08-20 15:45:14 -04:00
cmpxchg-local.h locking/atomic: cmpxchg: make generic a prefix 2021-05-26 13:20:50 +02:00
cmpxchg.h locking/atomic: delete !ARCH_ATOMIC remnants 2021-05-26 13:20:52 +02:00
compat.h riscv: compat: syscall: Add compat_sys_call_table implementation 2022-04-26 13:36:25 -07:00
current.h
delay.h
device.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 428 2019-06-05 17:37:16 +02:00
div64.h ARM: 9117/1: asm-generic: div64: Remove always-true __div64_const32_is_OK() 2021-08-20 11:39:28 +01:00
dma-mapping.h dma-mapping: bypass indirect calls for dma-direct 2018-12-13 21:06:18 +01:00
dma.h
early_ioremap.h mm/early_ioremap.c: remove redundant early_ioremap_shutdown() 2021-09-08 11:50:24 -07:00
emergency-restart.h
error-injection.h asm-generic/error-injection.h: fix a spelling mistake, and a coding style issue 2021-12-17 14:12:14 +01:00
exec.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36 2019-05-24 17:27:11 +02:00
export.h kbuild: link symbol CRCs at final link, removing CONFIG_MODULE_REL_CRCS 2022-05-24 16:33:20 +09:00
extable.h
fb.h
fixmap.h mm: introduce common STRUCT_PAGE_MAX_SHIFT define 2018-12-14 15:05:45 -08:00
flat.h binfmt_flat: remove the persistent argument from flat_get_addr_from_rp 2019-06-24 09:16:47 +10:00
ftrace.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
futex.h futex: Fix additional regressions 2021-12-11 23:31:51 +01:00
getorder.h asm-generic: force inlining of get_order() to work around gcc10 poor decision 2020-12-15 22:46:15 -08:00
gpio.h gpio: Avoid kernel.h inclusion where it's possible 2020-02-10 12:58:36 +01:00
hardirq.h irqstat: Move declaration into asm-generic/hardirq.h 2020-11-23 10:31:06 +01:00
hugetlb.h mm: change huge_ptep_clear_flush() to return the original pte 2022-05-13 16:48:55 -07:00
hw_irq.h
hyperv-tlfs.h KVM: x86: Add checks for reserved-to-zero Hyper-V hypercall fields 2022-02-10 13:50:36 -05:00
ide_iops.h
int-ll64.h int-ll64.h: define u{8,16,32,64} and s{8,16,32,64} based on uapi header 2018-06-07 17:34:38 -07:00
io.h asm-generic: updates for 6.0 2022-08-05 10:07:23 -07:00
ioctl.h
iomap.h parisc: Declare pci_iounmap() parisc version only when CONFIG_PCI enabled 2021-09-19 10:36:09 -07:00
irq_regs.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
irq_work.h
irq.h
irqflags.h
Kbuild xen: branch for v6.0-rc1 2022-08-04 15:10:55 -07:00
kdebug.h
kmap_size.h mm/highmem: Provide and use CONFIG_DEBUG_KMAP_LOCAL 2020-11-24 14:42:08 +01:00
kprobes.h treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
kvm_para.h
kvm_types.h KVM: Move x86's version of struct kvm_mmu_memory_cache to common code 2020-07-09 13:29:42 -04:00
linkage.h
local64.h
local.h
logic_io.h logic_io instance of iounmap() needs volatile on argument 2021-12-21 21:31:08 +01:00
mcs_spinlock.h
memory_model.h mm: remove CONFIG_DISCONTIGMEM 2021-06-29 10:53:55 -07:00
mm_hooks.h mm: remove arch_bprm_mm_init() hook 2020-01-23 10:41:16 -08:00
mmiowb_types.h asm-generic/mmiowb: Add generic implementation of mmiowb() tracking 2019-04-08 11:59:39 +01:00
mmiowb.h asm-generic/mmiowb: Allow mmiowb_set_pending() when preemptible() 2020-07-17 10:02:03 +01:00
mmu_context.h asm-generic: add generic MMU versions of mmu context functions 2020-10-26 16:45:03 +01:00
mmu.h
module.h
module.lds.h kbuild: preprocess module linker script 2020-09-25 00:36:41 +09:00
mshyperv.h Drivers: hv: vmbus: Propagate VMbus coherence to each VMbus device 2022-03-29 12:12:50 +00:00
msi.h Generic interrupt and irqchips subsystem: 2020-12-15 15:03:31 -08:00
nommu_context.h asm-generic: add generic MMU versions of mmu context functions 2020-10-26 16:45:03 +01:00
numa.h numa: Move numa implementation to common code 2021-01-14 15:08:55 -08:00
page.h c6x: remove architecture 2021-01-20 09:30:45 +01:00
param.h
parport.h
pci_iomap.h PCI: Stub __pci_ioport_map() for arches that don't support it at all 2022-07-29 12:01:00 -05:00
pci.h asm-generic: Add new pci.h and use it 2022-07-22 17:34:57 -05:00
percpu.h asm-generic: percpu: avoid Wshadow warning 2020-10-26 23:54:48 +00:00
pgalloc.h asm-generic: Prepare for riscv use of pud_alloc_one and pud_free 2022-01-19 17:54:08 -08:00
pgtable_uffd.h userfaultfd: wp: add pmd_swp_*uffd_wp() helpers 2020-04-07 10:43:39 -07:00
pgtable-nop4d.h mm: rename p4d_page_vaddr to p4d_pgtable and make it return pud_t * 2021-07-08 11:48:22 -07:00
pgtable-nopmd.h riscv/mm: fix two page table check related issues 2022-05-19 14:08:48 -07:00
pgtable-nopud.h mm: rename p4d_page_vaddr to p4d_pgtable and make it return pud_t * 2021-07-08 11:48:22 -07:00
preempt.h sched/core: Initialize the idle task with preemption disabled 2021-05-12 13:01:45 +02:00
qrwlock_types.h locking/qrwlock: Change "queue rwlock" to "queued rwlock" 2022-05-11 16:27:04 +02:00
qrwlock.h asm-generic changes for 5.19 2022-05-26 10:50:30 -07:00
qspinlock_types.h locking/qspinlock: Do not include atomic.h from qspinlock_types.h 2020-07-29 16:14:19 +02:00
qspinlock.h asm-generic: qspinlock: Indicate the use of mixed-size atomics 2022-05-11 11:49:47 -07:00
resource.h
rwonce.h asm/rwonce: Don't pull <asm/barrier.h> into 'asm-generic/rwonce.h' 2020-07-21 10:50:36 +01:00
seccomp.h seccomp: Use -1 marker for end of mode 1 syscall list 2020-07-10 16:01:52 -07:00
sections.h asm-generic: Refactor dereference_[kernel]_function_descriptor() 2022-02-16 23:25:11 +11:00
serial.h
set_memory.h
shmparam.h treewide: remove SPDX "WITH Linux-syscall-note" from kernel-space headers 2019-05-14 19:52:48 -07:00
signal.h
simd.h
softirq_stack.h arch/*: Disable softirq stacks on PREEMPT_RT. 2022-06-15 17:40:59 +02:00
spinlock_types.h asm-generic: ticket-lock: New generic ticket-based spinlock 2022-05-11 11:49:38 -07:00
spinlock.h asm-generic: ticket-lock: New generic ticket-based spinlock 2022-05-11 11:49:38 -07:00
statfs.h
string.h
switch_to.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36 2019-05-24 17:27:11 +02:00
syscall.h ptrace: Create ptrace_report_syscall_{entry,exit} in ptrace.h 2022-03-10 13:35:08 -06:00
syscalls.h
termios-base.h
termios.h
timex.h
tlb.h mmu_gather: fix the CONFIG_MMU_GATHER_NO_RANGE case 2022-07-22 09:28:34 -07:00
tlbflush.h
topology.h mm: replace CONFIG_NEED_MULTIPLE_NODES with CONFIG_NUMA 2021-06-29 10:53:55 -07:00
trace_clock.h
uaccess.h uaccess: remove CONFIG_SET_FS 2022-02-25 09:36:06 +01:00
unaligned.h asm-generic: fix __get_unaligned_be48() on 32 bit platforms 2022-04-12 16:31:38 -06:00
user.h
vermagic.h arch: split MODULE_ARCH_VERMAGIC definitions out to <asm/vermagic.h> 2020-04-23 10:50:26 +09:00
vga.h
vmlinux.lds.h sched: Reverse sched_class layout 2022-05-19 23:46:13 +02:00
vtime.h
word-at-a-time.h
xor.h lib/xor: make xor prototypes more friendly to compiler vectorization 2022-02-11 20:39:39 +11:00