Messages in this thread Patch in this message | | | From | kpark3469@gmail ... | Subject | [PATCH v3] arm: fix a wrong value returned from CALLER_ADDRn | Date | Thu, 14 Mar 2013 13:35:01 +0900 |
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From: Sahara <keun-o.park@windriver.com>
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 <keun-o.park@windriver.com> Reviewed-by: Dave Martin <dave.martin@linaro.org> --- arch/arm/kernel/return_address.c | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/arm/kernel/return_address.c b/arch/arm/kernel/return_address.c index 8085417..fafedd8 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; -- 1.7.1
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