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

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Date:   Fri, 23 Jun 2017 17:20:34 +0300
From:   Leonard Crestez <leonard.crestez@....com>
To:     Kieran Bingham <kieran@...uared.org.uk>,
        Jan Kiszka <jan.kiszka@...mens.com>
CC:     <linux-kernel@...r.kernel.org>
Subject: [PATCH 1/2] gdb/scripts: 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>
---
 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)
         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