Frederic Weisbecker 25269871db irq_work: Fix irq_work_claim() memory ordering ...

When irq_work_claim() finds IRQ_WORK_PENDING flag already set, we just
return and don't raise a new IPI. We expect the destination to see
and handle our latest updades thanks to the pairing atomic_xchg()
in irq_work_run_list().

But cmpxchg() doesn't guarantee a full memory barrier upon failure. So
it's possible that the destination misses our latest updates.

So use atomic_fetch_or() instead that is unconditionally fully ordered
and also performs exactly what we want here and simplify the code.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20191108160858.31665-3-frederic@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

2019-11-11 09:03:31 +01:00

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bpf

irq_work: Convert flags to atomic_t

2019-11-11 09:02:56 +01:00

cgroup

sched/topology: Don't try to build empty sched domains

2019-10-29 09:58:45 +01:00

configs

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debug

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dma

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events

perf/core: Start rejecting the syscall with attr.__reserved_2 set

2019-10-28 11:01:59 +01:00

gcov

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irq

irq/irqdomain: Update __irq_domain_alloc_fwnode() function documentation

2019-11-05 00:48:26 +01:00

livepatch

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locking

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power

PM: QoS: Introduce frequency QoS

2019-10-21 02:05:21 +02:00

printk

irq_work: Convert flags to atomic_t

2019-11-11 09:02:56 +01:00

rcu

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sched

sched: Fix pick_next_task() vs 'change' pattern race

2019-11-08 22:34:14 +01:00

time

timekeeping/vsyscall: Update VDSO data unconditionally

2019-11-04 23:02:53 +01:00

trace

irq_work: Convert flags to atomic_t

2019-11-11 09:02:56 +01:00

.gitignore

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acct.c

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async.c

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audit_fsnotify.c

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audit_tree.c

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audit_watch.c

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audit.c

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audit.h

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auditfilter.c

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auditsc.c

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backtracetest.c

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bounds.c

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capability.c

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compat.c

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configs.c

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context_tracking.c

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cpu_pm.c

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cpu.c

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crash_core.c

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crash_dump.c

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cred.c

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delayacct.c

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dma.c

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elfcore.c

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exec_domain.c

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exit.c

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extable.c

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fail_function.c

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fork.c

clone3: validate stack arguments

2019-11-05 15:50:14 +01:00

freezer.c

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futex.c

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gen_kheaders.sh

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groups.c

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hung_task.c

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iomem.c

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irq_work.c

irq_work: Fix irq_work_claim() memory ordering

2019-11-11 09:03:31 +01:00

jump_label.c

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kallsyms.c

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kcmp.c

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Kconfig.freezer

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Kconfig.hz

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Kconfig.locks

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Kconfig.preempt

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kcov.c

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kexec_core.c

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kexec_elf.c

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kexec_file.c

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kexec_internal.h

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kexec.c

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kheaders.c

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kmod.c

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kprobes.c

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ksysfs.c

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kthread.c

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latencytop.c

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Makefile

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module_signature.c

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module_signing.c

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module-internal.h

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module.c

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notifier.c

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nsproxy.c

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padata.c

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panic.c

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params.c

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pid_namespace.c

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pid.c

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profile.c

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ptrace.c

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range.c

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reboot.c

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relay.c

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resource.c

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rseq.c

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seccomp.c

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signal.c

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smp.c

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smpboot.c

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smpboot.h

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softirq.c

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stackleak.c

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stacktrace.c

stacktrace: Don't skip first entry on noncurrent tasks

2019-11-04 21:19:25 +01:00

stop_machine.c

stop_machine: Avoid potential race behaviour

2019-10-17 12:47:12 +02:00

sys_ni.c

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sys.c

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sysctl_binary.c

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sysctl.c

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task_work.c

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taskstats.c

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test_kprobes.c

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torture.c

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tracepoint.c

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tsacct.c

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ucount.c

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uid16.c

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uid16.h

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up.c

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user_namespace.c

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user-return-notifier.c

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user.c

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utsname_sysctl.c

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utsname.c

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watchdog_hld.c

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watchdog.c

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workqueue_internal.h

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workqueue.c

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