linux-kernel - [PATCH v2 1/2] scripts/gdb: lx-dmesg: Cast log

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Message-ID: <ba6f85dbb02ca980ebd0e2399b0649423399b565.1498481469.git.leonard.crestez@nxp.com>
Date:   Mon, 26 Jun 2017 15:52:21 +0300
From:   Leonard Crestez <leonard.crestez@....com>
To:     Jan Kiszka <jan.kiszka@...mens.com>,
        Kieran Bingham <kieran@...uared.org.uk>
CC:     <linux-kernel@...r.kernel.org>
Subject: [PATCH v2 1/2] scripts/gdb: lx-dmesg: Cast log_buf to void* for addr fetch

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@....com>
Reviewed-by: Jan Kiszka <jan.kiszka@...mens.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@....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"))
-- 
2.7.4