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Subject: Re: [PATCH v2 1/2] scripts/gdb: lx-dmesg: Cast log_buf to void* for
 addr fetch
To: Leonard Crestez <leonard.crestez@nxp.com>,
        Kieran Bingham <kieran@ksquared.org.uk>,
        Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
References: <ba6f85dbb02ca980ebd0e2399b0649423399b565.1498481469.git.leonard.crestez@nxp.com>
From: Jan Kiszka <jan.kiszka@siemens.com>
Message-ID: <7c6b5877-79f0-af01-f622-e5d7cd0bd866@siemens.com>
Date: Fri, 7 Jul 2017 11:15:48 +0200
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On 2017-06-26 14:52, 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@nxp.com>
> Reviewed-by: Jan Kiszka <jan.kiszka@siemens.com>
> 
> ---
> Changes since v1:
>  * Fix title (use "scripts/gdb" header instead of "gdb/scripts")
>  * Use "void *" instead of "void*"
> 
> Link: https://lkml.org/lkml/2017/6/23/461
> Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
> ---
>  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..f5a0303 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)
>          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"))
> 

Acked-by: Jan Kiszka <jan.kiszka@siemens.com>

Andrew, please pick this up.

Jan

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