From ae7dbaad23f0346dc4e2476be63a9a5a376ee472 Mon Sep 17 00:00:00 2001 From: Jan Kiszka Date: Tue, 17 Feb 2015 13:47:04 -0800 Subject: scripts/gdb: add lx-dmesg command This pokes into the log buffer of the debugged kernel, dumping it to the gdb console. Helping in case the target should or can no longer execute dmesg itself. Signed-off-by: Jan Kiszka Cc: Kay Sievers Cc: Thomas Gleixner Cc: Jason Wessel Cc: Andi Kleen Cc: Ben Widawsky Cc: Borislav Petkov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- scripts/gdb/linux/dmesg.py | 64 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 64 insertions(+) create mode 100644 scripts/gdb/linux/dmesg.py (limited to 'scripts/gdb/linux/dmesg.py') diff --git a/scripts/gdb/linux/dmesg.py b/scripts/gdb/linux/dmesg.py new file mode 100644 index 000000000000..7650f240ebcc --- /dev/null +++ b/scripts/gdb/linux/dmesg.py @@ -0,0 +1,64 @@ +# +# gdb helper commands and functions for Linux kernel debugging +# +# kernel log buffer dump +# +# Copyright (c) Siemens AG, 2011, 2012 +# +# Authors: +# Jan Kiszka +# +# This work is licensed under the terms of the GNU GPL version 2. +# + +import gdb +import string + +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("log_buf")).split()[0], 16) + log_first_idx = int(gdb.parse_and_eval("log_first_idx")) + log_next_idx = int(gdb.parse_and_eval("log_next_idx")) + log_buf_len = int(gdb.parse_and_eval("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 = inf.read_memory(start, length) + else: + log_buf_2nd_half = log_buf_len - log_first_idx + log_buf = inf.read_memory(start, log_buf_2nd_half) + \ + inf.read_memory(log_buf_addr, log_next_idx) + + 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]) + time_stamp = utils.read_u64(log_buf[pos:pos + 8]) + + for line in log_buf[pos + 16:pos + 16 + text_len].splitlines(): + gdb.write("[{time:12.6f}] {line}\n".format( + time=time_stamp / 1000000000.0, + line=line)) + + pos += length + + +LxDmesg() -- cgit v1.2.3 From 276d97d90a2485f9a830a7a8242e4317b24c896f Mon Sep 17 00:00:00 2001 From: Pantelis Koukousoulas Date: Tue, 17 Feb 2015 13:47:35 -0800 Subject: scripts/gdb: port to python3 / gdb7.7 I tried to use these scripts in an ubuntu 14.04 host (gdb 7.7 compiled against python 3.3) but there were several errors. I believe this patch fixes these issues so that the commands now work (I tested lx-symbols, lx-dmesg, lx-lsmod). Main issues that needed to be resolved: * In python 2 iterators have a "next()" method. In python 3 it is __next__() instead (so let's just add both). * In older python versions there was an implicit conversion in object.__format__() (used when an object is in string.format()) where it was converting the object to str first and then calling str's __format__(). This has now been removed so we must explicitly convert to str the objects for which we need to keep this behavior. * In dmesg.py: in python 3 log_buf is now a "memoryview" object which needs to be converted to a string in order to use string methods like "splitlines()". Luckily memoryview exists in python 2.7.6 as well, so we can convert log_buf to memoryview and use the same code in both python 2 and python 3. This version of the patch has now been tested with gdb 7.7 and both python 3.4 and python 2.7.6 (I think asking for at least python 2.7.6 is a reasonable requirement instead of complicating the code with version checks etc). Signed-off-by: Pantelis Koukousoulas Signed-off-by: Jan Kiszka Cc: Thomas Gleixner Cc: Jason Wessel Cc: Andi Kleen Cc: Ben Widawsky Cc: Borislav Petkov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- scripts/gdb/linux/dmesg.py | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'scripts/gdb/linux/dmesg.py') diff --git a/scripts/gdb/linux/dmesg.py b/scripts/gdb/linux/dmesg.py index 7650f240ebcc..3c947f0c5dad 100644 --- a/scripts/gdb/linux/dmesg.py +++ b/scripts/gdb/linux/dmesg.py @@ -51,9 +51,10 @@ class LxDmesg(gdb.Command): continue text_len = utils.read_u16(log_buf[pos + 10:pos + 12]) + text = log_buf[pos + 16:pos + 16 + text_len] time_stamp = utils.read_u64(log_buf[pos:pos + 8]) - for line in log_buf[pos + 16:pos + 16 + text_len].splitlines(): + for line in memoryview(text).tobytes().splitlines(): gdb.write("[{time:12.6f}] {line}\n".format( time=time_stamp / 1000000000.0, line=line)) -- cgit v1.2.3