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authorpeterz@infradead.org <peterz@infradead.org>2020-07-27 14:48:52 +0200
committerIngo Molnar <mingo@kernel.org>2020-07-27 15:13:29 +0200
commited00495333ccc80fc8fb86fb43773c3c2a499466 (patch)
tree64882e5a738ab148341521d4ac598038ce8afd81 /arch/x86/Kconfig.debug
parentba1f2b2eaa2a529dba722507c55ff3d761d325dd (diff)
locking/lockdep: Fix TRACE_IRQFLAGS vs. NMIs
Prior to commit: 859d069ee1dd ("lockdep: Prepare for NMI IRQ state tracking") IRQ state tracking was disabled in NMIs due to nmi_enter() doing lockdep_off() -- with the obvious requirement that NMI entry call nmi_enter() before trace_hardirqs_off(). [ AFAICT, PowerPC and SH violate this order on their NMI entry ] However, that commit explicitly changed lockdep_hardirqs_*() to ignore lockdep_off() and breaks every architecture that has irq-tracing in it's NMI entry that hasn't been fixed up (x86 being the only fixed one at this point). The reason for this change is that by ignoring lockdep_off() we can: - get rid of 'current->lockdep_recursion' in lockdep_assert_irqs*() which was going to to give header-recursion issues with the seqlock rework. - allow these lockdep_assert_*() macros to function in NMI context. Restore the previous state of things and allow an architecture to opt-in to the NMI IRQ tracking support, however instead of relying on lockdep_off(), rely on in_nmi(), both are part of nmi_enter() and so over-all entry ordering doesn't need to change. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20200727124852.GK119549@hirez.programming.kicks-ass.net
Diffstat (limited to 'arch/x86/Kconfig.debug')
-rw-r--r--arch/x86/Kconfig.debug3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index 0dd319e6e5b4..ee1d3c5834c6 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -3,6 +3,9 @@
config TRACE_IRQFLAGS_SUPPORT
def_bool y
+config TRACE_IRQFLAGS_NMI_SUPPORT
+ def_bool y
+
config EARLY_PRINTK_USB
bool