[stable 4.9.y 2/4] scripts/gdb: lx-dmesg: cast log_buf to void* for addr fetch

From: Florian Fainelli
Date: Thu Jan 07 2021 - 17:53:35 EST

From: Leonard Crestez <leonard.crestez@xxxxxxx>

commit c454756f47277b651ad41a5a163499294529e35d upstream

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

(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.

Link: http://lkml.kernel.org/r/ba6f85dbb02ca980ebd0e2399b0649423399b565.1498481469.git.leonard.crestez@xxxxxxx
Signed-off-by: Leonard Crestez <leonard.crestez@xxxxxxx>
Reviewed-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
Cc: Jason Wessel <jason.wessel@xxxxxxxxxxxxx>
Cc: Kieran Bingham <kieran@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
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 5afd1098e33a..f5a030333dfd 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"))