From: David S. Miller Date: Mon, 18 Aug 2008 03:39:08 +0000 (-0700) Subject: sparc64: Fix recursion in stack overflow detection handling. X-Git-Tag: v2.6.26.3~13 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=fbcd513d29df1398572db0b5bd1cc6cfecd4b2fd;p=platform%2Fkernel%2Flinux-stable.git sparc64: Fix recursion in stack overflow detection handling. [ Upstream commit c7498081a6f5d96c9f3243b6b5e020352903bfd2 ] 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 Signed-off-by: Greg Kroah-Hartman --- diff --git a/arch/sparc64/lib/mcount.S b/arch/sparc64/lib/mcount.S index 9e4534b485c7..89556aaad7c1 100644 --- a/arch/sparc64/lib/mcount.S +++ b/arch/sparc64/lib/mcount.S @@ -45,12 +45,23 @@ _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