From mboxrd@z Thu Jan 1 00:00:00 1970 From: gregkh@linuxfoundation.org (Greg Kroah-Hartman) Date: Sat, 26 Jul 2014 12:02:55 -0700 Subject: [PATCH 3.14 81/87] locking/mutex: Disable optimistic spinning on some architectures In-Reply-To: <20140726190214.530473925@linuxfoundation.org> References: <20140726190214.530473925@linuxfoundation.org> Message-ID: <20140726190217.233358653@linuxfoundation.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Peter Zijlstra commit 4badad352a6bb202ec68afa7a574c0bb961e5ebc upstream. The optimistic spin code assumes regular stores and cmpxchg() play nice; this is found to not be true for at least: parisc, sparc32, tile32, metag-lock1, arc-!llsc and hexagon. There is further wreckage, but this in particular seemed easy to trigger, so blacklist this. Opt in for known good archs. Signed-off-by: Peter Zijlstra Reported-by: Mikulas Patocka Cc: David Miller Cc: Chris Metcalf Cc: James Bottomley Cc: Vineet Gupta Cc: Jason Low Cc: Waiman Long Cc: "James E.J. Bottomley" Cc: Paul McKenney Cc: John David Anglin Cc: James Hogan Cc: Linus Torvalds Cc: Davidlohr Bueso Cc: Benjamin Herrenschmidt Cc: Catalin Marinas Cc: Russell King Cc: Will Deacon Cc: linux-arm-kernel at lists.infradead.org Cc: linux-kernel at vger.kernel.org Cc: linuxppc-dev at lists.ozlabs.org Cc: sparclinux at vger.kernel.org Link: http://lkml.kernel.org/r/20140606175316.GV13930 at laptop.programming.kicks-ass.net Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- arch/arm/Kconfig | 1 + arch/arm64/Kconfig | 1 + arch/powerpc/Kconfig | 1 + arch/sparc/Kconfig | 1 + arch/x86/Kconfig | 1 + kernel/Kconfig.locks | 5 ++++- 6 files changed, 9 insertions(+), 1 deletion(-) --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -6,6 +6,7 @@ config ARM select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST select ARCH_HAVE_CUSTOM_GPIO_H select ARCH_MIGHT_HAVE_PC_PARPORT + select ARCH_SUPPORTS_ATOMIC_RMW select ARCH_USE_BUILTIN_BSWAP select ARCH_USE_CMPXCHG_LOCKREF select ARCH_WANT_IPC_PARSE_VERSION --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -2,6 +2,7 @@ config ARM64 def_bool y select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE select ARCH_USE_CMPXCHG_LOCKREF + select ARCH_SUPPORTS_ATOMIC_RMW select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST select ARCH_WANT_OPTIONAL_GPIOLIB select ARCH_WANT_COMPAT_IPC_PARSE_VERSION --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -141,6 +141,7 @@ config PPC select HAVE_DEBUG_STACKOVERFLOW select HAVE_IRQ_EXIT_ON_IRQ_STACK select ARCH_USE_CMPXCHG_LOCKREF if PPC64 + select ARCH_SUPPORTS_ATOMIC_RMW config GENERIC_CSUM def_bool CPU_LITTLE_ENDIAN --- a/arch/sparc/Kconfig +++ b/arch/sparc/Kconfig @@ -77,6 +77,7 @@ config SPARC64 select ARCH_HAVE_NMI_SAFE_CMPXCHG select HAVE_C_RECORDMCOUNT select NO_BOOTMEM + select ARCH_SUPPORTS_ATOMIC_RMW config ARCH_DEFCONFIG string --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -127,6 +127,7 @@ config X86 select HAVE_DEBUG_STACKOVERFLOW select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64 select HAVE_CC_STACKPROTECTOR + select ARCH_SUPPORTS_ATOMIC_RMW config INSTRUCTION_DECODER def_bool y --- a/kernel/Kconfig.locks +++ b/kernel/Kconfig.locks @@ -220,6 +220,9 @@ config INLINE_WRITE_UNLOCK_IRQRESTORE endif +config ARCH_SUPPORTS_ATOMIC_RMW + bool + config MUTEX_SPIN_ON_OWNER def_bool y - depends on SMP && !DEBUG_MUTEXES + depends on SMP && !DEBUG_MUTEXES && ARCH_SUPPORTS_ATOMIC_RMW