Commit 64985c3a authored by Sven Schnelle's avatar Sven Schnelle Committed by Vasily Gorbik
Browse files

s390: use WRITE_ONCE when re-allocating async stack 



The code does:

S390_lowcore.async_stack = new + STACK_INIT_OFFSET;

But the compiler is free to first assign one value and
add the other value later. If a IRQ would be coming in
between these two operations, it would run with an invalid
stack. Prevent this by using WRITE_ONCE.

Signed-off-by: default avatarSven Schnelle <svens@linux.ibm.com>
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
parent b0d31159

arch/s390/kernel/setup.c

+1 −1
Original line number Diff line number Diff line
@@ -346,7 +346,7 @@ static int __init async_stack_realloc(void) 
	new = stack_alloc();

	if (!new)

		panic("Couldn't allocate async stack");

	S390_lowcore.async_stack = new + STACK_INIT_OFFSET;

	WRITE_ONCE(S390_lowcore.async_stack, new + STACK_INIT_OFFSET);

	free_pages(old, THREAD_SIZE_ORDER);

	return 0;

}