Commit d2b496e5 authored Dec 23, 2013 by Michael Ellerman Committed by Benjamin Herrenschmidt Feb 11, 2014

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 <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

parent 15075897

arch/powerpc/xmon/xmon.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -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) {

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