Patch "ARC: Call trace_hardirqs_on() before enabling irqs" has been added to the 4.7-stable tree
Subsystems (2)
This is a note to let you know that I've just added the patch titled
ARC: Call trace_hardirqs_on() before enabling irqs
to the 4.7-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arc-call-trace_hardirqs_on-before-enabling-irqs.patch
and it can be found in the queue-4.7 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.
Quoted 1 line
From
18b43e89d295cc65151c505c643c98fb2c320e59Mon Sep 17 00:00:00 2001
From: Daniel Mentz <[email protected]>
Date: Thu, 4 Aug 2016 17:56:53 -0700
Subject: ARC: Call trace_hardirqs_on() before enabling irqs
From: Daniel Mentz <[email protected]>
commit 18b43e89d295cc65151c505c643c98fb2c320e59 upstream.
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 ]---
--- arch/arc/include/asm/irqflags-compact.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
arch/arc/include/asm/irqflags-compact.h +1 -1
@@ -188,10 +188,10 @@ static inline int arch_irqs_disabled(voi .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__ */
Patches currently in stable-queue which might be from [email protected] are
queue-4.7/arc-call-trace_hardirqs_on-before-enabling-irqs.patch