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    SubjectRe: [PATCH 39/40] debug_core: Turn off tracing while in the debugger
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    On Thu, 2010-01-14 at 08:59 -0600, Jason Wessel wrote:
    > The kernel debugger should turn off kernel tracing any time the
    > debugger is active and restore it on resume.
    >
    > CC: Steven Rostedt <rostedt@goodmis.org>
    > Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
    > ---
    > kernel/debug/debug_core.c | 8 ++++++++
    > 1 files changed, 8 insertions(+), 0 deletions(-)
    >
    > diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
    > index 6ca3f7c..464aa65 100644
    > --- a/kernel/debug/debug_core.c
    > +++ b/kernel/debug/debug_core.c
    > @@ -474,6 +474,7 @@ static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs)
    > int sstep_tries = 100;
    > int error;
    > int i, cpu;
    > + int trace_on = 0;
    > acquirelock:
    > /*
    > * Interrupts will be restored by the 'trap return' code, except when
    > @@ -518,6 +519,8 @@ return_normal:
    > */
    > if (arch_kgdb_ops.correct_hw_break)
    > arch_kgdb_ops.correct_hw_break();
    > + if (trace_on)
    > + tracing_on();
    > atomic_set(&cpu_in_kgdb[cpu], 0);
    > touch_softlockup_watchdog_sync();
    > clocksource_touch_watchdog();
    > @@ -592,6 +595,9 @@ return_normal:
    > kgdb_single_step = 0;
    > kgdb_contthread = current;
    > exception_level = 0;
    > + trace_on = tracing_is_on();
    > + if (trace_on)
    > + tracing_off();

    Hmm, what happens if tracing gets turned on by something else? Will it
    break this code? If so, we may need to do something different here.

    -- Steve

    >
    > while (1) {
    > cpu_master_loop:
    > @@ -642,6 +648,8 @@ kgdb_restore:
    > else
    > kgdb_sstep_pid = 0;
    > }
    > + if (trace_on)
    > + tracing_on();
    > /* Free kgdb_active */
    > atomic_set(&kgdb_active, -1);
    > touch_softlockup_watchdog_sync();




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