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Commit 5d5dbc4e authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

s390: Prevent hotplug rwsem recursion 



The text patching functions which are invoked from jump_label and kprobes
code are protected against cpu hotplug at the call sites.

Use stop_machine_cpuslocked() to avoid recursion on the cpu hotplug
rwsem. stop_machine_cpuslocked() contains a lockdep assertion to catch any
unprotected callers.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarIngo Molnar <mingo@kernel.org>
Acked-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: linux-s390@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Link: http://lkml.kernel.org/r/20170524081549.354513406@linutronix.de
parent 9489cc8f

arch/s390/kernel/jump_label.c

+1 −1
Original line number Diff line number Diff line
@@ -93,7 +93,7 @@ void arch_jump_label_transform(struct jump_entry *entry, 
	args.entry = entry;

	args.type = type;



	stop_machine(__sm_arch_jump_label_transform, &args, NULL);

	stop_machine_cpuslocked(__sm_arch_jump_label_transform, &args, NULL);

}



void arch_jump_label_transform_static(struct jump_entry *entry,

arch/s390/kernel/kprobes.c

+2 −2
Original line number Diff line number Diff line
@@ -196,7 +196,7 @@ void arch_arm_kprobe(struct kprobe *p) 
{

	struct swap_insn_args args = {.p = p, .arm_kprobe = 1};



	stop_machine(swap_instruction, &args, NULL);

	stop_machine_cpuslocked(swap_instruction, &args, NULL);

}

NOKPROBE_SYMBOL(arch_arm_kprobe);
@@ -204,7 +204,7 @@ void arch_disarm_kprobe(struct kprobe *p) 
{

	struct swap_insn_args args = {.p = p, .arm_kprobe = 0};



	stop_machine(swap_instruction, &args, NULL);

	stop_machine_cpuslocked(swap_instruction, &args, NULL);

}

NOKPROBE_SYMBOL(arch_disarm_kprobe);