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.
CC: Kay Sievers <k...@vrfy.org>
Signed-off-by: Jan Kiszka <jan.kis...@siemens.com>
---
scripts/gdb/dmesg.py | 63 ++++++++++++++++++++++++++++++++++++++++++++
scripts/gdb/vmlinux-gdb.py | 1 +
2 files changed, 64 insertions(+), 0 deletions(-)
create mode 100644 scripts/gdb/dmesg.py
diff --git a/scripts/gdb/dmesg.py b/scripts/gdb/dmesg.py
new file mode 100644
index 0000000..d094f80
--- /dev/null
+++ b/scripts/gdb/dmesg.py
@@ -0,0 +1,63 @@
+#
+# gdb helper commands and functions for Linux kernel debugging
+#
+# kernel log buffer dump
+#
+# Copyright (c) 2011, 2012 Siemens AG
+#
+# Authors:
+# Jan Kiszka <jan.kis...@siemens.com>
+#
+# This work is licensed under the terms of the GNU GPL version 2.
+#
+
+import gdb
+import string
+
+from utils import *
+
+class LinuxDmesg(gdb.Command):
+ __doc__ = "Print Linux kernel log buffer."
+
+ def __init__(self):
+ super(LinuxDmesg, 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 = read_u16(log_buf[pos + 8 : pos + 10])
+ if length == 0:
+ if log_buf_2nd_half == -1:
+ print "Corrupted log buffer!"
+ break
+ pos = log_buf_2nd_half
+ continue
+
+ text_len = read_u16(log_buf[pos + 10 : pos + 12])
+ time_stamp = read_u64(log_buf[pos : pos + 8])
+
+ for line in log_buf[pos + 16 :
+ pos + 16 + text_len].splitlines():
+ print "[%13.6f] " % \
+ (time_stamp / 1000000000.0) + line
+
+ pos += length
+
+LinuxDmesg()
diff --git a/scripts/gdb/vmlinux-gdb.py b/scripts/gdb/vmlinux-gdb.py
index 50bca7c..8af7084 100644
--- a/scripts/gdb/vmlinux-gdb.py
+++ b/scripts/gdb/vmlinux-gdb.py
@@ -23,3 +23,4 @@ if gdb_version < "7.1":
else:
import utils
import symbols
+ import dmesg
--
1.7.3.4
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