With gcc 7.3.0: arch/m68k/kernel/signal.c: In function ‘mangle_kernel_stack’: arch/m68k/kernel/signal.c:654:3: warning: ISO C90 forbids variable length array ‘buf’ [-Wvla] unsigned long buf[fsize / 2]; /* yes, twice as much */ ^~~~~~~~ Replace the variable size by the upper limit, which is 168 bytes. Signed-off-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> --- arch/m68k/kernel/signal.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/m68k/kernel/signal.c b/arch/m68k/kernel/signal.c index e2a9421c57975034..87e7f3639839f559 100644 --- a/arch/m68k/kernel/signal.c +++ b/arch/m68k/kernel/signal.c @@ -651,7 +651,8 @@ static int mangle_kernel_stack(struct pt_regs *regs, int formatvec, regs->vector = formatvec & 0xfff; } else { struct switch_stack *sw = (struct switch_stack *)regs - 1; - unsigned long buf[fsize / 2]; /* yes, twice as much */ + /* yes, twice as much as max(sizeof(frame.un.fmt<x>)) */ + unsigned long buf[sizeof(((struct frame *)0)->un) / 2]; /* that'll make sure that expansion won't crap over data */ if (copy_from_user(buf + fsize / 4, fp, fsize)) -- 2.17.1