==================
files: arch/s390/kernel/debug.c
- include/asm-s390/debug.h
+ arch/s390/include/asm/debug.h
Description:
------------
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
Description: Allocates memory for a debug log
Must not be called within an interrupt handler
+----------------------------------------------------------------------------
+debug_info_t *debug_register_mode(char *name, int pages, int nr_areas,
+ int buf_size, mode_t mode, uid_t uid,
+ gid_t gid);
+
+Parameter: name: Name of debug log (e.g. used for debugfs entry)
+ pages: Number of pages, which will be allocated per area
+ nr_areas: Number of debug areas
+ buf_size: Size of data area in each debug entry
+ mode: File mode for debugfs files. E.g. S_IRWXUGO
+ uid: User ID for debugfs files. Currently only 0 is
+ supported.
+ gid: Group ID for debugfs files. Currently only 0 is
+ supported.
+
+Return Value: Handle for generated debug area
+ NULL if register failed
+
+Description: Allocates memory for a debug log
+ Must not be called within an interrupt handler
+
---------------------------------------------------------------------------
void debug_unregister (debug_info_t * id);
string plus two varargs one would need to allocate a (3 * sizeof(long))
byte data area in the debug_register() function.
+IMPORTANT: Using "%s" in sprintf event functions is dangerous. You can only
+use "%s" in the sprintf event functions, if the memory for the passed string is
+available as long as the debug feature exists. The reason behind this is that
+due to performance considerations only a pointer to the string is stored in
+the debug feature. If you log a string that is freed afterwards, you will get
+an OOPS when inspecting the debug feature, because then the debug feature will
+access the already freed memory.
NOTE: If using the sprintf view do NOT use other event/exception functions
than the sprintf-event and -exception functions.
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
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff