Patch "jump_label: Invoke jump_label_test() via early_initcall()" has been added to the 4.9-stable tree

Patch "jump_label: Invoke jump_label_test() via early_initcall()" has been added to the 4.9-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    jump_label: Invoke jump_label_test() via early_initcall()

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     jump_label-invoke-jump_label_test-via-early_initcall.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Tue Dec 12 13:26:17 CET 2017
From: Jason Baron <jbaron@akamai.com>
Date: Mon, 13 Nov 2017 16:48:47 -0500
Subject: jump_label: Invoke jump_label_test() via early_initcall()

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greter than or equal to SYSTEM_RUNNING then __init sections are no longer
valid (since the assumption is that they have been freed).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 */


Patches currently in stable-queue which might be from jbaron@akamai.com are

queue-4.9/module-set-__jump_table-alignment-to-8.patch
queue-4.9/jump_label-invoke-jump_label_test-via-early_initcall.patch
queue-4.9/dynamic-debug-howto-fix-optional-omitted-ending-line-number-to-be-large-instead-of-0.patch