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2012-05-01dynamic_debug: update Documentation/*, Kconfig.debugJim Cromie1-63/+121
In dynamic-debug-howto.txt: - add section: Debug Messages at Module Initialization Time - update flags indicators in example outputs to include '=' - make flags descriptions tabular - add item on '_' flag-char - add dyndbg, boot-args examples - rewrap some paragraphs with long lines In Kconfig.debug, note that compiling with -DDEBUG enables all pr_debug()s in that code. In kernel-parameters.txt, add dyndbg and module.dyndbg items, and deprecate ddebug_query. Signed-off-by: Jim Cromie <jim.cromie@gmail.com> Acked-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-01-25dynamic_debug: process multiple debug-queries on a lineJim Cromie1-15/+8
Insert ddebug_exec_queries() in place of ddebug_exec_query(). It splits the query string on [;\n], and calls ddebug_exec_query() on each. All queries are processed independent of errors, allowing a query to fail, for example when a module is not installed. Empty lines and comments are skipped. Errors are counted, and the last error seen (negative) or the number of callsites found (0 or positive) is returned. Return code checks are altered accordingly. With this, multiple queries can be given in ddebug_query, allowing more selective enabling of callsites. As a side effect, a set of commands can be batched in: cat cmd-file > $DBGMT/dynamic_debug/control We dont want a ddebug_query syntax error to kill the dynamic debug facility, so dynamic_debug_init() zeros ddebug_exec_queries()'s return code after logging the appropriate message, so that ddebug tables are preserved and $DBGMT/dynamic_debug/control file is created. This would be appropriate even without accepting multiple queries. This patch also alters ddebug_change() to return number of callsites matched (which typically is the same as number of callsites changed). ddebug_exec_query() also returns the number found, or a negative value if theres a parse error on the query. Splitting on [;\n] prevents their use in format-specs, but selecting callsites on punctuation is brittle anyway, meaningful and selective substrings are more typical. Note: splitting queries on ';' before handling trailing #comments means that a ';' also terminates a comment, and text after the ';' is treated as another query. This trailing query will almost certainly result in a parse error and thus have no effect other than the error message. The double corner case with unexpected results is: ddebug_query="func foo +p # enable foo ; +p" Signed-off-by: Jim Cromie <jim.cromie@gmail.com> Signed-off-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2012-01-25dynamic_debug: add trim_prefix() to provide source-root relative pathsJim Cromie1-3/+4
trim_prefix(path) skips past the absolute source path root, and returns the pointer to the relative path from there. It is used to shorten the displayed path in $DBGMT/dynamic_debug/control via ddebug_proc_show(), and in ddebug_change() to allow relative filenames to be used in applied queries. For example: ~# echo file kernel/freezer.c +p > $DBGMT/dynamic_debug/control kernel/freezer.c:128 [freezer]cancel_freezing p " clean up: %s\012" trim_prefix(path) insures common prefix before trimming it, so out-of-tree module paths are shown as full absolute paths. Signed-off-by: Jim Cromie <jim.cromie@gmail.com> Signed-off-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-03-28Merge branch 'docs-next' of git://git.lwn.net/linux-2.6Linus Torvalds1-2/+2
* 'docs-next' of git://git.lwn.net/linux-2.6: docs: update the development process document docs: fix dev_debug() braino in dynamic-debug-howto.txt
2011-03-25docs: fix dev_debug() braino in dynamic-debug-howto.txtJonathan Corbet1-2/+2
While looking at dynamic-debug-howto.txt, I noticed that it references dev_debug() (which doesn't exist) instead of dev_dbg() (which does exist). I'm lazy, so I choose to fix the document rather than changing every dev_dbg() call. Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2011-02-04Dynamic debug: Add more flagsBart Van Assche1-2/+10
Add flags that allow the user to specify via debugfs whether or not the module name, function name, line number and/or thread ID have to be included in the printed message. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Cc: Greg Banks <gnb@fmeh.org> Cc: Konrad Rzeszutek Wilk <konrad@darnok.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-10-22Dynamic Debug: Introduce ddebug_query= boot parameterThomas Renninger1-1/+21
Dynamic debug lacks the ability to enable debug messages at boot time. One could patch initramfs or service startup scripts to write to /sys/../dynamic_debug/control, but this sucks. This patch makes it possible to pass a query in the same format one can write to /sys/../dynamic_debug/control via boot param. When dynamic debug gets initialized, this query will automatically be applied. Signed-off-by: Thomas Renninger <trenn@suse.de> Acked-by: jbaron@redhat.com Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-03-25Dynamic debug: allow simple quoting of wordsGreg Banks1-6/+14
Allow simple quoting of words in the dynamic debug control language. This allows more natural specification when using the control language to match against printk formats, e.g #echo -n 'format "Setting node for non-present cpu" +p' > /mnt/debugfs/dynamic_debug/control instead of #echo -n 'format Setting\040node\040for\040non-present\040cpu +p' > /mnt/debugfs/dynamic_debug/control Adjust the dynamic debug documention to describe that and provide a new example. Adjust the existing examples in the documentation to reflect the current whitespace escaping behaviour when reading the control file. Fix some minor documentation trailing whitespace. Signed-off-by: Greg Banks <gnb@melbourne.sgi.com> Acked-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-03-25dynamic debug: update docsJason Baron1-0/+232
updates the documentation for 'dynamic debug' feature. Signed-off-by: Greg Banks <gnb@sgi.com> Signed-off-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>