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997acaf6b4
We generally expect local_irq_save() and local_irq_restore() to be paired and sanely nested, and so local_irq_restore() expects to be called with irqs disabled. Thus, within local_irq_restore() we only trace irq flag changes when unmasking irqs. This means that a sequence such as: | local_irq_disable(); | local_irq_save(flags); | local_irq_enable(); | local_irq_restore(flags); ... is liable to break things, as the local_irq_restore() would mask irqs without tracing this change. Similar problems may exist for architectures whose arch_irq_restore() function depends on being called with irqs disabled. We don't consider such sequences to be a good idea, so let's define those as forbidden, and add tooling to detect such broken cases. This patch adds debug code to WARN() when raw_local_irq_restore() is called with irqs enabled. As raw_local_irq_restore() is expected to pair with raw_local_irq_save(), it should never be called with irqs enabled. To avoid the possibility of circular header dependencies between irqflags.h and bug.h, the warning is handled in a separate C file. The new code is all conditional on a new CONFIG_DEBUG_IRQFLAGS symbol which is independent of CONFIG_TRACE_IRQFLAGS. As noted above such cases will confuse lockdep, so CONFIG_DEBUG_LOCKDEP now selects CONFIG_DEBUG_IRQFLAGS. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20210111153707.10071-1-mark.rutland@arm.com
35 lines
1.3 KiB
Makefile
35 lines
1.3 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0
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# Any varying coverage in these files is non-deterministic
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# and is generally not a function of system call inputs.
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KCOV_INSTRUMENT := n
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obj-y += mutex.o semaphore.o rwsem.o percpu-rwsem.o
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# Avoid recursion lockdep -> KCSAN -> ... -> lockdep.
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KCSAN_SANITIZE_lockdep.o := n
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ifdef CONFIG_FUNCTION_TRACER
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CFLAGS_REMOVE_lockdep.o = $(CC_FLAGS_FTRACE)
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CFLAGS_REMOVE_lockdep_proc.o = $(CC_FLAGS_FTRACE)
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CFLAGS_REMOVE_mutex-debug.o = $(CC_FLAGS_FTRACE)
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CFLAGS_REMOVE_rtmutex-debug.o = $(CC_FLAGS_FTRACE)
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endif
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obj-$(CONFIG_DEBUG_IRQFLAGS) += irqflag-debug.o
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obj-$(CONFIG_DEBUG_MUTEXES) += mutex-debug.o
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obj-$(CONFIG_LOCKDEP) += lockdep.o
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ifeq ($(CONFIG_PROC_FS),y)
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obj-$(CONFIG_LOCKDEP) += lockdep_proc.o
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endif
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obj-$(CONFIG_SMP) += spinlock.o
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obj-$(CONFIG_LOCK_SPIN_ON_OWNER) += osq_lock.o
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obj-$(CONFIG_PROVE_LOCKING) += spinlock.o
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obj-$(CONFIG_QUEUED_SPINLOCKS) += qspinlock.o
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obj-$(CONFIG_RT_MUTEXES) += rtmutex.o
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obj-$(CONFIG_DEBUG_RT_MUTEXES) += rtmutex-debug.o
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obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o
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obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
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obj-$(CONFIG_QUEUED_RWLOCKS) += qrwlock.o
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obj-$(CONFIG_LOCK_TORTURE_TEST) += locktorture.o
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obj-$(CONFIG_WW_MUTEX_SELFTEST) += test-ww_mutex.o
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obj-$(CONFIG_LOCK_EVENT_COUNTS) += lock_events.o
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