linux-bl808/scripts/gdb/linux/dmesg.py
Leonard Crestez c454756f47 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.

Link: http://lkml.kernel.org/r/ba6f85dbb02ca980ebd0e2399b0649423399b565.1498481469.git.leonard.crestez@nxp.com
Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
Reviewed-by: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Kieran Bingham <kieran@ksquared.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-12 16:26:01 -07:00

66 lines
2.1 KiB
Python

#
# gdb helper commands and functions for Linux kernel debugging
#
# kernel log buffer dump
#
# Copyright (c) Siemens AG, 2011, 2012
#
# Authors:
# Jan Kiszka <jan.kiszka@siemens.com>
#
# This work is licensed under the terms of the GNU GPL version 2.
#
import gdb
from linux import utils
class LxDmesg(gdb.Command):
"""Print Linux kernel log buffer."""
def __init__(self):
super(LxDmesg, self).__init__("lx-dmesg", gdb.COMMAND_DATA)
def invoke(self, arg, from_tty):
log_buf_addr = int(str(gdb.parse_and_eval(
"(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"))
inf = gdb.inferiors()[0]
start = log_buf_addr + log_first_idx
if log_first_idx < log_next_idx:
log_buf_2nd_half = -1
length = log_next_idx - log_first_idx
log_buf = utils.read_memoryview(inf, start, length).tobytes()
else:
log_buf_2nd_half = log_buf_len - log_first_idx
a = utils.read_memoryview(inf, start, log_buf_2nd_half)
b = utils.read_memoryview(inf, log_buf_addr, log_next_idx)
log_buf = a.tobytes() + b.tobytes()
pos = 0
while pos < log_buf.__len__():
length = utils.read_u16(log_buf[pos + 8:pos + 10])
if length == 0:
if log_buf_2nd_half == -1:
gdb.write("Corrupted log buffer!\n")
break
pos = log_buf_2nd_half
continue
text_len = utils.read_u16(log_buf[pos + 10:pos + 12])
text = log_buf[pos + 16:pos + 16 + text_len].decode()
time_stamp = utils.read_u64(log_buf[pos:pos + 8])
for line in text.splitlines():
gdb.write("[{time:12.6f}] {line}\n".format(
time=time_stamp / 1000000000.0,
line=line))
pos += length
LxDmesg()