From: Keun-O Park Date: Mon, 18 Mar 2013 06:32:53 +0000 (+0100) Subject: ARM: 7676/1: fix a wrong value returned from CALLER_ADDRn X-Git-Tag: sz_174~28 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=128487e4ee654abd3c958db54e73702b872502a9 ARM: 7676/1: fix a wrong value returned from CALLER_ADDRn This makes return_address() return a correct value for CALLER_ADDRn. To have a correct value from CALLER_ADDRn, we need to fix three points. * The unwind_frame() does not update frame->lr but frame->pc for backtrace. So frame->pc is meaningful for backtrace. * data.level should be adjusted by adding 2 additional iteration levels. With the current +1 level adjustment, the result of CALLER_ADDR1 will be the same return address with CALLER_ADDR0. * The initialization of data.addr to NULL is needed. When unwind_fame() fails right after data.level reaches zero, the routine returns data.addr which has uninitialized garbage value. Signed-off-by: Sahara Reviewed-by: Dave Martin Signed-off-by: Russell King --- diff --git a/arch/arm/kernel/return_address.c b/arch/arm/kernel/return_address.c index 8085417555dd..fafedd86885d 100644 --- a/arch/arm/kernel/return_address.c +++ b/arch/arm/kernel/return_address.c @@ -26,7 +26,7 @@ static int save_return_addr(struct stackframe *frame, void *d) struct return_address_data *data = d; if (!data->level) { - data->addr = (void *)frame->lr; + data->addr = (void *)frame->pc; return 1; } else { @@ -41,7 +41,8 @@ void *return_address(unsigned int level) struct stackframe frame; register unsigned long current_sp asm ("sp"); - data.level = level + 1; + data.level = level + 2; + data.addr = NULL; frame.fp = (unsigned long)__builtin_frame_address(0); frame.sp = current_sp;