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@@ -12,8 +12,8 @@ where log records can be stored efficiently in memory, where each component
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One purpose of this is to inspect the debug logs after a production system crash
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in order to analyze the reason for the crash.
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If the system still runs but only a subcomponent which uses dbf failes,
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-it is possible to look at the debug logs on a live system via the Linux proc
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-filesystem.
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+it is possible to look at the debug logs on a live system via the Linux
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+debugfs filesystem.
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The debug feature may also very useful for kernel and driver development.
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Design:
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@@ -52,16 +52,18 @@ Each debug entry contains the following data:
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- Flag, if entry is an exception or not
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The debug logs can be inspected in a live system through entries in
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-the proc-filesystem. Under the path /proc/s390dbf there is
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+the debugfs-filesystem. Under the toplevel directory "s390dbf" there is
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a directory for each registered component, which is named like the
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-corresponding component.
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+corresponding component. The debugfs normally should be mounted to
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+/sys/kernel/debug therefore the debug feature can be accessed unter
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+/sys/kernel/debug/s390dbf.
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The content of the directories are files which represent different views
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to the debug log. Each component can decide which views should be
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used through registering them with the function debug_register_view().
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Predefined views for hex/ascii, sprintf and raw binary data are provided.
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It is also possible to define other views. The content of
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-a view can be inspected simply by reading the corresponding proc file.
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+a view can be inspected simply by reading the corresponding debugfs file.
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All debug logs have an an actual debug level (range from 0 to 6).
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The default level is 3. Event and Exception functions have a 'level'
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@@ -69,14 +71,14 @@ parameter. Only debug entries with a level that is lower or equal
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than the actual level are written to the log. This means, when
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writing events, high priority log entries should have a low level
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value whereas low priority entries should have a high one.
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-The actual debug level can be changed with the help of the proc-filesystem
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-through writing a number string "x" to the 'level' proc file which is
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+The actual debug level can be changed with the help of the debugfs-filesystem
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+through writing a number string "x" to the 'level' debugfs file which is
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provided for every debug log. Debugging can be switched off completely
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-by using "-" on the 'level' proc file.
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+by using "-" on the 'level' debugfs file.
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Example:
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-> echo "-" > /proc/s390dbf/dasd/level
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+> echo "-" > /sys/kernel/debug/s390dbf/dasd/level
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It is also possible to deactivate the debug feature globally for every
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debug log. You can change the behavior using 2 sysctl parameters in
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@@ -99,11 +101,11 @@ Kernel Interfaces:
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------------------
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----------------------------------------------------------------------------
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-debug_info_t *debug_register(char *name, int pages_index, int nr_areas,
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+debug_info_t *debug_register(char *name, int pages, int nr_areas,
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int buf_size);
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-Parameter: name: Name of debug log (e.g. used for proc entry)
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- pages_index: 2^pages_index pages will be allocated per area
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+Parameter: name: Name of debug log (e.g. used for debugfs entry)
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+ pages: number of pages, which will be allocated per area
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nr_areas: number of debug areas
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buf_size: size of data area in each debug entry
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@@ -134,7 +136,7 @@ Return Value: none
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Description: Sets new actual debug level if new_level is valid.
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---------------------------------------------------------------------------
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-+void debug_stop_all(void);
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+void debug_stop_all(void);
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Parameter: none
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@@ -270,7 +272,7 @@ Parameter: id: handle for debug log
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Return Value: 0 : ok
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< 0: Error
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-Description: registers new debug view and creates proc dir entry
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+Description: registers new debug view and creates debugfs dir entry
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---------------------------------------------------------------------------
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int debug_unregister_view (debug_info_t * id, struct debug_view *view);
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@@ -281,7 +283,7 @@ Parameter: id: handle for debug log
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Return Value: 0 : ok
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< 0: Error
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-Description: unregisters debug view and removes proc dir entry
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+Description: unregisters debug view and removes debugfs dir entry
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@@ -308,7 +310,7 @@ static int init(void)
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{
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/* register 4 debug areas with one page each and 4 byte data field */
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- debug_info = debug_register ("test", 0, 4, 4 );
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+ debug_info = debug_register ("test", 1, 4, 4 );
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debug_register_view(debug_info,&debug_hex_ascii_view);
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debug_register_view(debug_info,&debug_raw_view);
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@@ -343,7 +345,7 @@ static int init(void)
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/* register 4 debug areas with one page each and data field for */
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/* format string pointer + 2 varargs (= 3 * sizeof(long)) */
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- debug_info = debug_register ("test", 0, 4, sizeof(long) * 3);
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+ debug_info = debug_register ("test", 1, 4, sizeof(long) * 3);
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debug_register_view(debug_info,&debug_sprintf_view);
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debug_sprintf_event(debug_info, 2 , "first event in %s:%i\n",__FILE__,__LINE__);
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@@ -362,16 +364,16 @@ module_exit(cleanup);
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-ProcFS Interface
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+Debugfs Interface
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----------------
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Views to the debug logs can be investigated through reading the corresponding
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-proc-files:
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+debugfs-files:
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Example:
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-> ls /proc/s390dbf/dasd
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-flush hex_ascii level raw
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-> cat /proc/s390dbf/dasd/hex_ascii | sort +1
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+> ls /sys/kernel/debug/s390dbf/dasd
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+flush hex_ascii level pages raw
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+> cat /sys/kernel/debug/s390dbf/dasd/hex_ascii | sort +1
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00 00974733272:680099 2 - 02 0006ad7e 07 ea 4a 90 | ....
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00 00974733272:682210 2 - 02 0006ade6 46 52 45 45 | FREE
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00 00974733272:682213 2 - 02 0006adf6 07 ea 4a 90 | ....
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@@ -391,25 +393,36 @@ Changing the debug level
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Example:
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-> cat /proc/s390dbf/dasd/level
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+> cat /sys/kernel/debug/s390dbf/dasd/level
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3
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-> echo "5" > /proc/s390dbf/dasd/level
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-> cat /proc/s390dbf/dasd/level
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+> echo "5" > /sys/kernel/debug/s390dbf/dasd/level
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+> cat /sys/kernel/debug/s390dbf/dasd/level
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5
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Flushing debug areas
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--------------------
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Debug areas can be flushed with piping the number of the desired
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-area (0...n) to the proc file "flush". When using "-" all debug areas
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+area (0...n) to the debugfs file "flush". When using "-" all debug areas
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are flushed.
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Examples:
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1. Flush debug area 0:
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-> echo "0" > /proc/s390dbf/dasd/flush
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+> echo "0" > /sys/kernel/debug/s390dbf/dasd/flush
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2. Flush all debug areas:
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-> echo "-" > /proc/s390dbf/dasd/flush
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+> echo "-" > /sys/kernel/debug/s390dbf/dasd/flush
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+
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+Changing the size of debug areas
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+------------------------------------
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+It is possible the change the size of debug areas through piping
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+the number of pages to the debugfs file "pages". The resize request will
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+also flush the debug areas.
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+
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+Example:
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+
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+Define 4 pages for the debug areas of debug feature "dasd":
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+> echo "4" > /sys/kernel/debug/s390dbf/dasd/pages
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Stooping the debug feature
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--------------------------
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@@ -491,7 +504,7 @@ Defining views
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--------------
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Views are specified with the 'debug_view' structure. There are defined
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-callback functions which are used for reading and writing the proc files:
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+callback functions which are used for reading and writing the debugfs files:
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struct debug_view {
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char name[DEBUG_MAX_PROCF_LEN];
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@@ -525,7 +538,7 @@ typedef int (debug_input_proc_t) (debug_info_t* id,
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The "private_data" member can be used as pointer to view specific data.
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It is not used by the debug feature itself.
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-The output when reading a debug-proc file is structured like this:
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+The output when reading a debugfs file is structured like this:
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"prolog_proc output"
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@@ -534,13 +547,13 @@ The output when reading a debug-proc file is structured like this:
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"header_proc output 3" "format_proc output 3"
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...
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-When a view is read from the proc fs, the Debug Feature calls the
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+When a view is read from the debugfs, the Debug Feature calls the
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'prolog_proc' once for writing the prolog.
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Then 'header_proc' and 'format_proc' are called for each
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existing debug entry.
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The input_proc can be used to implement functionality when it is written to
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-the view (e.g. like with 'echo "0" > /proc/s390dbf/dasd/level).
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+the view (e.g. like with 'echo "0" > /sys/kernel/debug/s390dbf/dasd/level).
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For header_proc there can be used the default function
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debug_dflt_header_fn() which is defined in in debug.h.
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@@ -602,7 +615,7 @@ debug_info = debug_register ("test", 0, 4, 4 ));
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debug_register_view(debug_info, &debug_test_view);
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for(i = 0; i < 10; i ++) debug_int_event(debug_info, 1, i);
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-> cat /proc/s390dbf/test/myview
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+> cat /sys/kernel/debug/s390dbf/test/myview
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00 00964419734:611402 1 - 00 88042ca This error...........
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00 00964419734:611405 1 - 00 88042ca That error...........
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00 00964419734:611408 1 - 00 88042ca Problem..............
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Michael Holzheu