From a2d375eda771a6a4866f3717a8ed81b63acb1dbd Mon Sep 17 00:00:00 2001 From: Jim Cromie Date: Mon, 31 Aug 2020 12:22:09 -0600 Subject: [PATCH] dyndbg: refine export, rename to dynamic_debug_exec_queries() commit 4c0d77828d4f ("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: 4c0d77828d4f ("dyndbg: export ddebug_exec_queries") Signed-off-by: Jim Cromie Link: https://lore.kernel.org/r/20200831182210.850852-3-jim.cromie@gmail.com Signed-off-by: Greg Kroah-Hartman --- include/linux/dynamic_debug.h | 20 ++++++++++++++++---- lib/dynamic_debug.c | 27 +++++++++++++++++++++++++-- 2 files changed, 41 insertions(+), 6 deletions(-) diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h index aa9ff9e..8aa0c7c 100644 --- a/include/linux/dynamic_debug.h +++ b/include/linux/dynamic_debug.h @@ -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 #include +#include 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 diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index 01b7d02..08e4b05 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -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 -- 2.7.4