This is a note to let you know that I've just added the patch titled
powerpc/64: Don't trace irqs-off at interrupt return to soft-disabled context
to the 4.14-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:
powerpc-64-don-t-trace-irqs-off-at-interrupt-return-to-soft-disabled-context.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Fri Mar 16 15:43:17 CET 2018
From: Nicholas Piggin <npiggin@xxxxxxxxx>
Date: Fri, 17 Nov 2017 02:00:50 +1000
Subject: powerpc/64: Don't trace irqs-off at interrupt return to soft-disabled context
From: Nicholas Piggin <npiggin@xxxxxxxxx>
[ Upstream commit acb1feab320e38588fccc568e3767761f494976f ]
When an interrupt is returning to a soft-disabled context (which can
happen for non-maskable interrupts or synchronous interrupts), it goes
through the motions of soft-disabling again, including calling
TRACE_DISABLE_INTS (i.e., trace_hardirqs_off()).
This is not necessary, because we must already be soft-disabled in the
interrupt context, it also may be causing crashes in the irq tracing
code to re-enter as an nmi. Replace it with a warning to ensure that
soft-interrupts are still disabled.
Fixes: 7c0482e3d055 ("powerpc/irq: Fix another case of lazy IRQ state getting out of sync")
Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/kernel/entry_64.S | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -939,9 +939,13 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
beq 1f
rlwinm r7,r7,0,~PACA_IRQ_HARD_DIS
stb r7,PACAIRQHAPPENED(r13)
-1: li r0,0
- stb r0,PACASOFTIRQEN(r13);
- TRACE_DISABLE_INTS
+1:
+#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_BUG)
+ /* The interrupt should not have soft enabled. */
+ lbz r7,PACASOFTIRQEN(r13)
+1: tdnei r7,0
+ EMIT_BUG_ENTRY 1b,__FILE__,__LINE__,BUGFLAG_WARNING
+#endif
b .Ldo_restore
/*
Patches currently in stable-queue which might be from npiggin@xxxxxxxxx are
queue-4.14/powerpc-64-don-t-trace-irqs-off-at-interrupt-return-to-soft-disabled-context.patch