Re: [PATCH 1/2] gdb/scripts: lx-dmesg: Cast log_buf to void* for addr fetch

From: Jan Kiszka
Date: Fri Jun 23 2017 - 12:02:44 EST


On 2017-06-23 16:20, Leonard Crestez wrote:
> In some cases it is possible for the str() conversion here to throw
> encoding errors because log_buf might not point to valid ascii. For
> example:
>
> (gdb) python print str(gdb.parse_and_eval("log_buf"))
> Traceback (most recent call last):
> File "<string>", line 1, in <module>
> UnicodeEncodeError: 'ascii' codec can't encode character u'\u0303' in
> position 24: ordinal not in range(128)
>
> Avoid this by explicitly casting to (void *) inside the gdb expression.
>
> Signed-off-by: Leonard Crestez <leonard.crestez@xxxxxxx>
> ---
> scripts/gdb/linux/dmesg.py | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/scripts/gdb/linux/dmesg.py b/scripts/gdb/linux/dmesg.py
> index 5afd109..6f8d2b2 100644
> --- a/scripts/gdb/linux/dmesg.py
> +++ b/scripts/gdb/linux/dmesg.py
> @@ -24,7 +24,7 @@ class LxDmesg(gdb.Command):
>
> def invoke(self, arg, from_tty):
> log_buf_addr = int(str(gdb.parse_and_eval(
> - "'printk.c'::log_buf")).split()[0], 16)
> + "(void*)'printk.c'::log_buf")).split()[0], 16)

Nit: (void *)

> log_first_idx = int(gdb.parse_and_eval("'printk.c'::log_first_idx"))
> log_next_idx = int(gdb.parse_and_eval("'printk.c'::log_next_idx"))
> log_buf_len = int(gdb.parse_and_eval("'printk.c'::log_buf_len"))
>

Looks good, makes sense to me.

Reviewed-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>

Jan

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