[PATCH 2/2] process: change from __backtrace to dump_stack_regs in show_regs
nicolas.pitre at linaro.org
Wed Aug 24 14:57:48 EDT 2011
On Wed, 24 Aug 2011, Laura Abbott wrote:
> Currently, show_regs calls __backtrace which does
> nothing if CONIFG_FRAME_POINTER is not set. Switch to
> dump_stack_regs to show the backtrace from a given
> set of registers.
> Signed-off-by: Laura Abbott <lauraa at codeaurora.org>
> arch/arm/kernel/process.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
> diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
> index 1a347f4..6f11213 100644
> --- a/arch/arm/kernel/process.c
> +++ b/arch/arm/kernel/process.c
> @@ -319,7 +319,7 @@ void show_regs(struct pt_regs * regs)
> printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm);
> - __backtrace();
> + dump_stack_regs(regs);
This is not equivalent. A call to __backtrace() will display a call
trace leading to this show_regs(). Given that you defined
dump_stack_regs(regs) as dump_backtrace(regs, NULL), the trace will
instead contain calls leading up to the point where those regs were
A better way to achieve what you want would be:
- remove the __backtrace entry point from lib/backtrace.S
- define __backtrace() in kernel/traps.c as a call to
dump_backtrace(NULL, NULL) which will have the same effect as the
assembly code for __backtrace().
- realize that dump_stack() is already doing exactly that, therefore...
- use dump_stack() in show_regs() which is the only caller of
__backtrace and get rid of __backtrace entirely.
Obviously the above can be collapsed in one patch.
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