Commit b318d41f authored Jan 09, 2023 by Heiko Carstens Committed by Greg Kroah-Hartman Jan 18, 2023

s390/percpu: add READ_ONCE() to arch_this_cpu_to_op_simple()



commit e3f360db08d55a14112bd27454e616a24296a8b0 upstream.

Make sure that *ptr__ within arch_this_cpu_to_op_simple() is only
dereferenced once by using READ_ONCE(). Otherwise the compiler could
generate incorrect code.

Cc: <stable@vger.kernel.org>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent f6da927c

arch/s390/include/asm/percpu.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -31,7 +31,7 @@
		pcp_op_T__ *ptr__; \
		preempt_disable_notrace(); \
		ptr__ = raw_cpu_ptr(&(pcp)); \
		prev__ = *ptr__; \
		prev__ = READ_ONCE(*ptr__); \
		do { \
		old__ = prev__; \
		new__ = old__ op (val); \