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 4.15-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-4.15 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 15:11:08 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-4.15/powerpc-64-don-t-trace-irqs-off-at-interrupt-return-to-soft-disabled-context.patch