From 18b43e89d295cc65151c505c643c98fb2c320e59 Mon Sep 17 00:00:00 2001 From: Daniel Mentz Date: Thu, 4 Aug 2016 17:56:53 -0700 Subject: [PATCH] ARC: Call trace_hardirqs_on() before enabling irqs trace_hardirqs_on_caller() in lockdep.c expects to be called before, not after interrupts are actually enabled. The following comment in kernel/locking/lockdep.c substantiates this claim: " /* * We're enabling irqs and according to our state above irqs weren't * already enabled, yet we find the hardware thinks they are in fact * enabled.. someone messed up their IRQ state tracing. */ " An example can be found in include/linux/irqflags.h: do { trace_hardirqs_on(); raw_local_irq_enable(); } while (0) Without this change, we hit the following DEBUG_LOCKS_WARN_ON. [ 7.760000] ------------[ cut here ]------------ [ 7.760000] WARNING: CPU: 0 PID: 1 at kernel/locking/lockdep.c:2711 resume_user_mode_begin+0x48/0xf0 [ 7.770000] DEBUG_LOCKS_WARN_ON(!irqs_disabled()) [ 7.780000] Modules linked in: [ 7.780000] CPU: 0 PID: 1 Comm: init Not tainted 4.7.0-00003-gc668bb9-dirty #366 [ 7.790000] [ 7.790000] Stack Trace: [ 7.790000] arc_unwind_core.constprop.1+0xa4/0x118 [ 7.800000] warn_slowpath_fmt+0x72/0x158 [ 7.800000] resume_user_mode_begin+0x48/0xf0 [ 7.810000] ---[ end trace 6f6a7a8fae20d2f0 ]--- Signed-off-by: Daniel Mentz Cc: Signed-off-by: Vineet Gupta --- arch/arc/include/asm/irqflags-compact.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arc/include/asm/irqflags-compact.h b/arch/arc/include/asm/irqflags-compact.h index c1d36458bfb7..4c6eed80cd8b 100644 --- a/arch/arc/include/asm/irqflags-compact.h +++ b/arch/arc/include/asm/irqflags-compact.h @@ -188,10 +188,10 @@ static inline int arch_irqs_disabled(void) .endm .macro IRQ_ENABLE scratch + TRACE_ASM_IRQ_ENABLE lr \scratch, [status32] or \scratch, \scratch, (STATUS_E1_MASK | STATUS_E2_MASK) flag \scratch - TRACE_ASM_IRQ_ENABLE .endm #endif /* __ASSEMBLY__ */ -- 2.11.0