Messages in this thread | | | Date | Mon, 13 Nov 2017 14:15:26 -0800 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH] jump_label: invoke jump_label_test() via early_initcall() |
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On Mon, Nov 13, 2017 at 04:48:47PM -0500, Jason Baron wrote: > Fengguang Wu reported that running the rcuperf test during boot can cause > the jump_label_test() to hit a WARN_ON(). The issue is that the core jump > label code relies on kernel_text_address() to detect when it can no longer > update branches that may be contained in __init sections. The > kernel_text_address() in turn assumes that if the system_state variable is > greter than or equal to SYSTEM_RUNNING then __init sections are no longer > valid (since the assumption is that they have been freed). However, when > rcuperf is setup to run in early boot it can call kernel_power_off() which > sets the system_state to SYSTEM_POWER_OFF. > > Since rcuperf initialization is invoked via a module_init(), we can make > the dependency of jump_label_test() needing to complete before rcuperf > explicit by calling it via early_initcall(). > > Reported-by: Fengguang Wu <fengguang.wu@intel.com> > Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Steven Rostedt <rostedt@goodmis.org> > Cc: Ingo Molnar <mingo@kernel.org> > Signed-off-by: Jason Baron <jbaron@akamai.com>
Looks way simpler than handling this three times in rcuperf, rcutorture, and locktorture!
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> --- > kernel/jump_label.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/jump_label.c b/kernel/jump_label.c > index 0bf2e8f5..7c3774a 100644 > --- a/kernel/jump_label.c > +++ b/kernel/jump_label.c > @@ -769,7 +769,7 @@ static __init int jump_label_test(void) > > return 0; > } > -late_initcall(jump_label_test); > +early_initcall(jump_label_test); > #endif /* STATIC_KEYS_SELFTEST */ > > #endif /* HAVE_JUMP_LABEL */ > -- > 2.6.1 >
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