From c7498081a6f5d96c9f3243b6b5e020352903bfd2 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Tue, 12 Aug 2008 02:03:49 -0700 Subject: [PATCH] sparc64: Fix recursion in stack overflow detection handling. The calls down into prom_printf() when we detect an overflowed stack can recurse again since the overflow stack will be "below" the current kernel stack limit. Prevent this by just returning straight if we are on the stack overflow safe stack already. Signed-off-by: David S. Miller --- arch/sparc64/lib/mcount.S | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/arch/sparc64/lib/mcount.S b/arch/sparc64/lib/mcount.S index 7735a7a60533..734caf0cec09 100644 --- a/arch/sparc64/lib/mcount.S +++ b/arch/sparc64/lib/mcount.S @@ -48,12 +48,23 @@ mcount: sub %g3, STACK_BIAS, %g3 cmp %sp, %g3 bg,pt %xcc, 1f - sethi %hi(panicstring), %g3 + nop + /* If we are already on ovstack, don't hop onto it + * again, we are already trying to output the stack overflow + * message. + */ sethi %hi(ovstack), %g7 ! cant move to panic stack fast enough or %g7, %lo(ovstack), %g7 - add %g7, OVSTACKSIZE, %g7 + add %g7, OVSTACKSIZE, %g3 + sub %g3, STACK_BIAS + 192, %g3 sub %g7, STACK_BIAS, %g7 - mov %g7, %sp + cmp %sp, %g7 + blu,pn %xcc, 2f + cmp %sp, %g3 + bleu,pn %xcc, 1f + nop +2: mov %g3, %sp + sethi %hi(panicstring), %g3 call prom_printf or %g3, %lo(panicstring), %o0 call prom_halt -- 2.20.1