The patch titled
Subject: ARM: prevent tracing IPI_CPU_BACKTRACE
has been added to the -mm tree. Its filename is
arm-prevent-tracing-ipi_cpu_backtrace.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/arm-prevent-tracing-ipi_cpu_backtrace.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/arm-prevent-tracing-ipi_cpu_backtrace.patch
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------------------------------------------------------
From: Arnd Bergmann <arnd@xxxxxxxx>
Subject: ARM: prevent tracing IPI_CPU_BACKTRACE
Patch series "compiler: allow all arches to enable
CONFIG_OPTIMIZE_INLINING", v3.
This patch (of 11):
When function tracing for IPIs is enabled, we get a warning for an
overflow of the ipi_types array with the IPI_CPU_BACKTRACE type as
triggered by raise_nmi():
arch/arm/kernel/smp.c: In function 'raise_nmi':
arch/arm/kernel/smp.c:489:2: error: array subscript is above array bounds [-Werror=array-bounds]
trace_ipi_raise(target, ipi_types[ipinr]);
This is a correct warning as we actually overflow the array here.
This patch raise_nmi() to call __smp_cross_call() instead of
smp_cross_call(), to avoid calling into ftrace. For clarification, I'm
also adding a two new code comments describing how this one is special.
The warning appears to have shown up after patch e7273ff49acf ("ARM:
8488/1: Make IPI_CPU_BACKTRACE a "non-secure" SGI"), which changed the
number assignment from '15' to '8', but as far as I can tell has existed
since the IPI tracepoints were first introduced. If we decide to backport
this patch to stable kernels, we probably need to backport e7273ff49acf as
well.
[yamada.masahiro@xxxxxxxxxxxxx: rebase on v5.1-rc1]
Link: http://lkml.kernel.org/r/20190423034959.13525-2-yamada.masahiro@xxxxxxxxxxxxx
Fixes: e7273ff49acf ("ARM: 8488/1: Make IPI_CPU_BACKTRACE a "non-secure" SGI")
Fixes: 365ec7b17327 ("ARM: add IPI tracepoints") # v3.17
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Christophe Leroy <christophe.leroy@xxxxxx>
Cc: Mathieu Malaterre <malat@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: Stefan Agner <stefan@xxxxxxxx>
Cc: Boris Brezillon <bbrezillon@xxxxxxxxxx>
Cc: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
Cc: Richard Weinberger <richard@xxxxxx>
Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
Cc: Brian Norris <computersforpeace@xxxxxxxxx>
Cc: Marek Vasut <marek.vasut@xxxxxxxxx>
Cc: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/arm/include/asm/hardirq.h | 1 +
arch/arm/kernel/smp.c | 6 +++++-
2 files changed, 6 insertions(+), 1 deletion(-)
--- a/arch/arm/include/asm/hardirq.h~arm-prevent-tracing-ipi_cpu_backtrace
+++ a/arch/arm/include/asm/hardirq.h
@@ -6,6 +6,7 @@
#include <linux/threads.h>
#include <asm/irq.h>
+/* number of IPIS _not_ including IPI_CPU_BACKTRACE */
#define NR_IPI 7
typedef struct {
--- a/arch/arm/kernel/smp.c~arm-prevent-tracing-ipi_cpu_backtrace
+++ a/arch/arm/kernel/smp.c
@@ -70,6 +70,10 @@ enum ipi_msg_type {
IPI_CPU_STOP,
IPI_IRQ_WORK,
IPI_COMPLETION,
+ /*
+ * CPU_BACKTRACE is special and not included in NR_IPI
+ * or tracable with trace_ipi_*
+ */
IPI_CPU_BACKTRACE,
/*
* SGI8-15 can be reserved by secure firmware, and thus may
@@ -797,7 +801,7 @@ core_initcall(register_cpufreq_notifier)
static void raise_nmi(cpumask_t *mask)
{
- smp_cross_call(mask, IPI_CPU_BACKTRACE);
+ __smp_cross_call(mask, IPI_CPU_BACKTRACE);
}
void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
_
Patches currently in -mm which might be from arnd@xxxxxxxx are
fs-select-avoid-clang-stack-usage-warning.patch
arm-prevent-tracing-ipi_cpu_backtrace.patch
