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dyndbg: refine export, rename to dynamic_debug_exec_queries()

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commit 4c0d77828d ("dyndbg: export ddebug_exec_queries") had a few
problems:
 - broken non DYNAMIC_DEBUG_CORE configs, sparse warning
 - the exported function modifies query string, breaks on RO strings.
 - func name follows internal convention, shouldn't be exposed as is.

1st is fixed in header with ifdefd function prototype or stub defn.
Also remove an obsolete HAVE-symbol ifdef-comment, and add others.

Fix others by wrapping existing internal function with a new one,
named in accordance with module-prefix naming convention, before
export hits v5.9.0.  In new function, copy query string to a local
buffer, so users can pass hard-coded/RO queries, and internal function
can be used unchanged.

Fixes: 4c0d77828d ("dyndbg: export ddebug_exec_queries")
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Link: https://lore.kernel.org/r/20200831182210.850852-3-jim.cromie@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jim Cromie 2020-08-31 12:22:09 -06:00 committed by Greg Kroah-Hartman
parent b52a95eac1
commit a2d375eda7
2 changed files with 41 additions and 6 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

20
include/linux/dynamic_debug.h
View file

@ -49,6 +49,10 @@ struct _ddebug {
#if defined(CONFIG_DYNAMIC_DEBUG_CORE)
/* exported for module authors to exercise >control */
int dynamic_debug_exec_queries(const char *query, const char *modname);
int ddebug_add_module(struct _ddebug *tab, unsigned int n,
const char *modname);
extern int ddebug_remove_module(const char *mod_name);
@ -105,7 +109,7 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
static_branch_unlikely(&descriptor.key.dd_key_false)
#endif
#else /* !HAVE_JUMP_LABEL */
#else /* !CONFIG_JUMP_LABEL */
#define _DPRINTK_KEY_INIT
@ -117,7 +121,7 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
unlikely(descriptor.flags & _DPRINTK_FLAGS_PRINT)
#endif
#endif
#endif /* CONFIG_JUMP_LABEL */
#define __dynamic_func_call(id, fmt, func, ...) do { \
DEFINE_DYNAMIC_DEBUG_METADATA(id, fmt); \
@ -172,10 +176,11 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
KERN_DEBUG, prefix_str, prefix_type, \
rowsize, groupsize, buf, len, ascii)
#else
#else /* !CONFIG_DYNAMIC_DEBUG_CORE */
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/printk.h>
static inline int ddebug_add_module(struct _ddebug *tab, unsigned int n,
const char *modname)
@ -210,6 +215,13 @@ static inline int ddebug_dyndbg_module_param_cb(char *param, char *val,
print_hex_dump(KERN_DEBUG, prefix_str, prefix_type, \
rowsize, groupsize, buf, len, ascii); \
} while (0)
#endif
static inline int dynamic_debug_exec_queries(const char *query, const char *modname)
{
pr_warn("kernel not built with CONFIG_DYNAMIC_DEBUG_CORE\n");
return 0;
}
#endif /* !CONFIG_DYNAMIC_DEBUG_CORE */
#endif

27
lib/dynamic_debug.c
View file

@ -525,7 +525,7 @@ static int ddebug_exec_query(char *query_string, const char *modname)
last error or number of matching callsites. Module name is either
in param (for boot arg) or perhaps in query string.
*/
int ddebug_exec_queries(char *query, const char *modname)
static int ddebug_exec_queries(char *query, const char *modname)
{
char *split;
int i, errs = 0, exitcode = 0, rc, nfound = 0;
@ -557,7 +557,30 @@ int ddebug_exec_queries(char *query, const char *modname)
return exitcode;
return nfound;
}
EXPORT_SYMBOL_GPL(ddebug_exec_queries);
/**
* dynamic_debug_exec_queries - select and change dynamic-debug prints
* @query: query-string described in admin-guide/dynamic-debug-howto
* @modname: string containing module name, usually &module.mod_name
*
* This uses the >/proc/dynamic_debug/control reader, allowing module
* authors to modify their dynamic-debug callsites. The modname is
* canonically struct module.mod_name, but can also be null or a
* module-wildcard, for example: "drm*".
*/
int dynamic_debug_exec_queries(const char *query, const char *modname)
{
int rc;
char *qry = kstrndup(query, PAGE_SIZE, GFP_KERNEL);
if (!query)
return -ENOMEM;
rc = ddebug_exec_queries(qry, modname);
kfree(qry);
return rc;
}
EXPORT_SYMBOL_GPL(dynamic_debug_exec_queries);
#define PREFIX_SIZE 64