ca210ba32e
When CONFIG_PRINTK_CALLER is set, struct printk_log contains an additional member caller_id. This affects the offset of the log text. Account for this by using the type information from gdb to determine all the offsets instead of using hardcoded values. This fixes following error: (gdb) lx-dmesg Python Exception <class 'ValueError'> embedded null character: Error occurred in Python command: embedded null character The read_u* utility functions now take an offset argument to make them easier to use. Link: http://lkml.kernel.org/r/20191011142500.2339-1-joel.colledge@linbit.com Signed-off-by: Joel Colledge <joel.colledge@linbit.com> Reviewed-by: Jan Kiszka <jan.kiszka@siemens.com> Cc: Kieran Bingham <kbingham@kernel.org> Cc: Leonard Crestez <leonard.crestez@nxp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
82 lines
2.8 KiB
Python
82 lines
2.8 KiB
Python
#
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# gdb helper commands and functions for Linux kernel debugging
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#
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# kernel log buffer dump
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#
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# Copyright (c) Siemens AG, 2011, 2012
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#
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# Authors:
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# Jan Kiszka <jan.kiszka@siemens.com>
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#
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# This work is licensed under the terms of the GNU GPL version 2.
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#
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import gdb
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import sys
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from linux import utils
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printk_log_type = utils.CachedType("struct printk_log")
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class LxDmesg(gdb.Command):
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"""Print Linux kernel log buffer."""
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def __init__(self):
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super(LxDmesg, self).__init__("lx-dmesg", gdb.COMMAND_DATA)
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def invoke(self, arg, from_tty):
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log_buf_addr = int(str(gdb.parse_and_eval(
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"(void *)'printk.c'::log_buf")).split()[0], 16)
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log_first_idx = int(gdb.parse_and_eval("'printk.c'::log_first_idx"))
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log_next_idx = int(gdb.parse_and_eval("'printk.c'::log_next_idx"))
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log_buf_len = int(gdb.parse_and_eval("'printk.c'::log_buf_len"))
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inf = gdb.inferiors()[0]
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start = log_buf_addr + log_first_idx
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if log_first_idx < log_next_idx:
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log_buf_2nd_half = -1
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length = log_next_idx - log_first_idx
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log_buf = utils.read_memoryview(inf, start, length).tobytes()
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else:
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log_buf_2nd_half = log_buf_len - log_first_idx
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a = utils.read_memoryview(inf, start, log_buf_2nd_half)
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b = utils.read_memoryview(inf, log_buf_addr, log_next_idx)
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log_buf = a.tobytes() + b.tobytes()
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length_offset = printk_log_type.get_type()['len'].bitpos // 8
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text_len_offset = printk_log_type.get_type()['text_len'].bitpos // 8
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time_stamp_offset = printk_log_type.get_type()['ts_nsec'].bitpos // 8
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text_offset = printk_log_type.get_type().sizeof
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pos = 0
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while pos < log_buf.__len__():
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length = utils.read_u16(log_buf, pos + length_offset)
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if length == 0:
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if log_buf_2nd_half == -1:
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gdb.write("Corrupted log buffer!\n")
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break
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pos = log_buf_2nd_half
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continue
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text_len = utils.read_u16(log_buf, pos + text_len_offset)
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text_start = pos + text_offset
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text = log_buf[text_start:text_start + text_len].decode(
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encoding='utf8', errors='replace')
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time_stamp = utils.read_u64(log_buf, pos + time_stamp_offset)
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for line in text.splitlines():
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msg = u"[{time:12.6f}] {line}\n".format(
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time=time_stamp / 1000000000.0,
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line=line)
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# With python2 gdb.write will attempt to convert unicode to
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# ascii and might fail so pass an utf8-encoded str instead.
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if sys.hexversion < 0x03000000:
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msg = msg.encode(encoding='utf8', errors='replace')
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gdb.write(msg)
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pos += length
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LxDmesg()
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