(e.g. device drivers) can have one separate debug log.
One purpose of this is to inspect the debug logs after a production system crash
in order to analyze the reason for the crash.
-If the system still runs but only a subcomponent which uses dbf failes,
+If the system still runs but only a subcomponent which uses dbf fails,
it is possible to look at the debug logs on a live system via the Linux
debugfs filesystem.
The debug feature may also very useful for kernel and driver development.
that the records which describe the origin of the exception are not
overwritten when a wrap around for the current area occurs.
-The debug areas itselve are also ordered in form of a ring buffer.
+The debug areas themselves are also ordered in form of a ring buffer.
When an exception is thrown in the last debug area, the following debug
entries are then written again in the very first area.
the debugfs-filesystem. Under the toplevel directory "s390dbf" there is
a directory for each registered component, which is named like the
corresponding component. The debugfs normally should be mounted to
-/sys/kernel/debug therefore the debug feature can be accessed unter
+/sys/kernel/debug therefore the debug feature can be accessed under
/sys/kernel/debug/s390dbf.
The content of the directories are files which represent different views
It is also possible to define other views. The content of
a view can be inspected simply by reading the corresponding debugfs file.
-All debug logs have an an actual debug level (range from 0 to 6).
+All debug logs have an actual debug level (range from 0 to 6).
The default level is 3. Event and Exception functions have a 'level'
parameter. Only debug entries with a level that is lower or equal
than the actual level are written to the log. This means, when
It is also possible to deactivate the debug feature globally for every
debug log. You can change the behavior using 2 sysctl parameters in
/proc/sys/s390dbf:
-There are currently 2 possible triggers, which stop the debug feature
-globally. The first possbility is to use the "debug_active" sysctl. If
+There are currently 2 possible triggers, which stop the debug feature
+globally. The first possibility is to use the "debug_active" sysctl. If
set to 1 the debug feature is running. If "debug_active" is set to 0 the
debug feature is turned off.
-The second trigger which stops the debug feature is an kernel oops.
+The second trigger which stops the debug feature is a kernel oops.
That prevents the debug feature from overwriting debug information that
happened before the oops. After an oops you can reactivate the debug feature
by piping 1 to /proc/sys/s390dbf/debug_active. Nevertheless, its not
-suggested to use an oopsed kernel in an production environment.
+suggested to use an oopsed kernel in a production environment.
If you want to disallow the deactivation of the debug feature, you can use
the "debug_stoppable" sysctl. If you set "debug_stoppable" to 0 the debug
feature cannot be stopped. If the debug feature is already stopped, it
The raw view returns a bytestream as the debug areas are stored in memory.
The sprintf view formats the debug entries in the same way as the sprintf
-function would do. The sprintf event/expection functions write to the
+function would do. The sprintf event/exception functions write to the
debug entry a pointer to the format string (size = sizeof(long))
and for each vararg a long value. So e.g. for a debug entry with a format
string plus two varargs one would need to allocate a (3 * sizeof(long))
the view (e.g. like with 'echo "0" > /sys/kernel/debug/s390dbf/dasd/level).
For header_proc there can be used the default function
-debug_dflt_header_fn() which is defined in in debug.h.
+debug_dflt_header_fn() which is defined in debug.h.
and which produces the same header output as the predefined views.
E.g:
00 00964419409:440761 2 - 00 88023ec
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