4.9-stable review patch. If anyone has any objections, please let me know.
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From: Jason Baron jbaron@akamai.com
[ Upstream commit 92ee46efeb505ead3ab06d3c5ce695637ed5f152 ]
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in turn assumes that if the system_state variable is greter than or equal to SYSTEM_RUNNING then __init sections are no longer valid (since the assumption is that they have been freed).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 Signed-off-by: Jason Baron jbaron@akamai.com Acked-by: Paul E. McKenney paulmck@linux.vnet.ibm.com Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Peter Zijlstra peterz@infradead.org Cc: Steven Rostedt rostedt@goodmis.org Cc: Thomas Gleixner tglx@linutronix.de Link: http://lkml.kernel.org/r/1510609727-2238-1-git-send-email-jbaron@akamai.com Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/jump_label.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -612,7 +612,7 @@ 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 */