From d2b496e5e1fa7a6796534e435440eb9d3ed184dd Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Mon, 23 Dec 2013 23:46:06 +1100 Subject: [PATCH] powerpc/xmon: Don't signal we've entered until we're finished printing Currently we set our cpu's bit in cpus_in_xmon, and then we take the output lock and print the exception information. This can race with the master cpu entering the command loop and printing the backtrace. The result is that the backtrace gets garbled with another cpu's exception print out. Fix it by delaying the set of cpus_in_xmon until we are finished printing. Signed-off-by: Michael Ellerman Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/xmon/xmon.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c index d712b23974ecab..b07909850f7715 100644 --- a/arch/powerpc/xmon/xmon.c +++ b/arch/powerpc/xmon/xmon.c @@ -404,7 +404,6 @@ static int xmon_core(struct pt_regs *regs, int fromipi) } xmon_fault_jmp[cpu] = recurse_jmp; - cpumask_set_cpu(cpu, &cpus_in_xmon); bp = NULL; if ((regs->msr & (MSR_IR|MSR_PR|MSR_64BIT)) == (MSR_IR|MSR_64BIT)) @@ -426,6 +425,8 @@ static int xmon_core(struct pt_regs *regs, int fromipi) release_output_lock(); } + cpumask_set_cpu(cpu, &cpus_in_xmon); + waiting: secondary = 1; while (secondary && !xmon_gate) {