From: Joel Colledge <joel.colledge@xxxxxxxxxx> [ Upstream commit ca210ba32ef7537b02731bfe255ed8eb1e4e2b59 ] 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@xxxxxxxxxx Signed-off-by: Joel Colledge <joel.colledge@xxxxxxxxxx> Reviewed-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx> Cc: Kieran Bingham <kbingham@xxxxxxxxxx> Cc: Leonard Crestez <leonard.crestez@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- scripts/gdb/linux/dmesg.py | 16 ++++++++++++---- scripts/gdb/linux/utils.py | 25 +++++++++++++------------ 2 files changed, 25 insertions(+), 16 deletions(-) diff --git a/scripts/gdb/linux/dmesg.py b/scripts/gdb/linux/dmesg.py index 6d2e09a2ad2f9..2fa7bb83885f0 100644 --- a/scripts/gdb/linux/dmesg.py +++ b/scripts/gdb/linux/dmesg.py @@ -16,6 +16,8 @@ import sys from linux import utils +printk_log_type = utils.CachedType("struct printk_log") + class LxDmesg(gdb.Command): """Print Linux kernel log buffer.""" @@ -42,9 +44,14 @@ class LxDmesg(gdb.Command): b = utils.read_memoryview(inf, log_buf_addr, log_next_idx) log_buf = a.tobytes() + b.tobytes() + length_offset = printk_log_type.get_type()['len'].bitpos // 8 + text_len_offset = printk_log_type.get_type()['text_len'].bitpos // 8 + time_stamp_offset = printk_log_type.get_type()['ts_nsec'].bitpos // 8 + text_offset = printk_log_type.get_type().sizeof + pos = 0 while pos < log_buf.__len__(): - length = utils.read_u16(log_buf[pos + 8:pos + 10]) + length = utils.read_u16(log_buf, pos + length_offset) if length == 0: if log_buf_2nd_half == -1: gdb.write("Corrupted log buffer!\n") @@ -52,10 +59,11 @@ class LxDmesg(gdb.Command): 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( + text_len = utils.read_u16(log_buf, pos + text_len_offset) + text_start = pos + text_offset + text = log_buf[text_start:text_start + text_len].decode( encoding='utf8', errors='replace') - time_stamp = utils.read_u64(log_buf[pos:pos + 8]) + time_stamp = utils.read_u64(log_buf, pos + time_stamp_offset) for line in text.splitlines(): msg = u"[{time:12.6f}] {line}\n".format( diff --git a/scripts/gdb/linux/utils.py b/scripts/gdb/linux/utils.py index bc67126118c4d..ea94221dbd392 100644 --- a/scripts/gdb/linux/utils.py +++ b/scripts/gdb/linux/utils.py @@ -92,15 +92,16 @@ def read_memoryview(inf, start, length): return memoryview(inf.read_memory(start, length)) -def read_u16(buffer): +def read_u16(buffer, offset): + buffer_val = buffer[offset:offset + 2] value = [0, 0] - if type(buffer[0]) is str: - value[0] = ord(buffer[0]) - value[1] = ord(buffer[1]) + if type(buffer_val[0]) is str: + value[0] = ord(buffer_val[0]) + value[1] = ord(buffer_val[1]) else: - value[0] = buffer[0] - value[1] = buffer[1] + value[0] = buffer_val[0] + value[1] = buffer_val[1] if get_target_endianness() == LITTLE_ENDIAN: return value[0] + (value[1] << 8) @@ -108,18 +109,18 @@ def read_u16(buffer): return value[1] + (value[0] << 8) -def read_u32(buffer): +def read_u32(buffer, offset): if get_target_endianness() == LITTLE_ENDIAN: - return read_u16(buffer[0:2]) + (read_u16(buffer[2:4]) << 16) + return read_u16(buffer, offset) + (read_u16(buffer, offset + 2) << 16) else: - return read_u16(buffer[2:4]) + (read_u16(buffer[0:2]) << 16) + return read_u16(buffer, offset + 2) + (read_u16(buffer, offset) << 16) -def read_u64(buffer): +def read_u64(buffer, offset): if get_target_endianness() == LITTLE_ENDIAN: - return read_u32(buffer[0:4]) + (read_u32(buffer[4:8]) << 32) + return read_u32(buffer, offset) + (read_u32(buffer, offset + 4) << 32) else: - return read_u32(buffer[4:8]) + (read_u32(buffer[0:4]) << 32) + return read_u32(buffer, offset + 4) + (read_u32(buffer, offset) << 32) target_arch = None -- 2.20.1
