Merge 4.4.143 into android-4.4

Changes in 4.4.143
	compiler, clang: suppress warning for unused static inline functions
	compiler, clang: properly override 'inline' for clang
	compiler, clang: always inline when CONFIG_OPTIMIZE_INLINING is disabled
	compiler-gcc.h: Add __attribute__((gnu_inline)) to all inline declarations
	x86/asm: Add _ASM_ARG* constants for argument registers to <asm/asm.h>
	Revert "sit: reload iphdr in ipip6_rcv"
	ocfs2: subsystem.su_mutex is required while accessing the item->ci_parent
	bcm63xx_enet: correct clock usage
	bcm63xx_enet: do not write to random DMA channel on BCM6345
	crypto: crypto4xx - remove bad list_del
	crypto: crypto4xx - fix crypto4xx_build_pdr, crypto4xx_build_sdr leak
	atm: zatm: Fix potential Spectre v1
	net: dccp: avoid crash in ccid3_hc_rx_send_feedback()
	net: dccp: switch rx_tstamp_last_feedback to monotonic clock
	net/mlx5: Fix incorrect raw command length parsing
	net: sungem: fix rx checksum support
	qed: Limit msix vectors in kdump kernel to the minimum required count.
	r8152: napi hangup fix after disconnect
	tcp: fix Fast Open key endianness
	tcp: prevent bogus FRTO undos with non-SACK flows
	vhost_net: validate sock before trying to put its fd
	net_sched: blackhole: tell upper qdisc about dropped packets
	net/mlx5: Fix command interface race in polling mode
	net: cxgb3_main: fix potential Spectre v1
	rtlwifi: rtl8821ae: fix firmware is not ready to run
	MIPS: Call dump_stack() from show_regs()
	MIPS: Use async IPIs for arch_trigger_cpumask_backtrace()
	netfilter: ebtables: reject non-bridge targets
	KEYS: DNS: fix parsing multiple options
	rds: avoid unenecessary cong_update in loop transport
	net/nfc: Avoid stalls when nfc_alloc_send_skb() returned NULL.
	Linux 4.4.143

Change-Id: Icacfd188cbb6075bf82a48ec1066e8653eb73ae4
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

1 files changed, 29 insertions, 2 deletions

diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
index 054a22c0873b..9684a0d22d97 100644
--- a/arch/mips/kernel/process.c
+++ b/arch/mips/kernel/process.c
@@ -633,21 +633,48 @@ unsigned long arch_align_stack(unsigned long sp)
 	return sp & ALMASK;
 }
 
+static DEFINE_PER_CPU(struct call_single_data, backtrace_csd);
+static struct cpumask backtrace_csd_busy;
+
 static void arch_dump_stack(void *info)
 {
 	struct pt_regs *regs;
+	static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED;
 
+	arch_spin_lock(&lock);
 	regs = get_irq_regs();
 
 	if (regs)
 		show_regs(regs);
+	else
+		dump_stack();
+	arch_spin_unlock(&lock);
 
-	dump_stack();
+	cpumask_clear_cpu(smp_processor_id(), &backtrace_csd_busy);
 }
 
 void arch_trigger_all_cpu_backtrace(bool include_self)
 {
-	smp_call_function(arch_dump_stack, NULL, 1);
+	struct call_single_data *csd;
+	int cpu;
+
+	for_each_cpu(cpu, cpu_online_mask) {
+		/*
+		 * If we previously sent an IPI to the target CPU & it hasn't
+		 * cleared its bit in the busy cpumask then it didn't handle
+		 * our previous IPI & it's not safe for us to reuse the
+		 * call_single_data_t.
+		 */
+		if (cpumask_test_and_set_cpu(cpu, &backtrace_csd_busy)) {
+			pr_warn("Unable to send backtrace IPI to CPU%u - perhaps it hung?\n",
+				cpu);
+			continue;
+		}
+
+		csd = &per_cpu(backtrace_csd, cpu);
+		csd->func = arch_dump_stack;
+		smp_call_function_single_async(cpu, csd);
+	}
 }
 
 int mips_get_process_fp_mode(struct task_struct *task)