In order to drop the pointer connecting _ddebug records to _callsites, we need to elevate the latter; we need to track it in (internal) ddebug_tables, and set it in ddebug_add_module. That last part exposes it by interface to module.c, so we add a field to load_info, and adjust load_module to initialize it from the elf section.
Its possible that this closes a hole created when __dyndbg_callsites section was added, and wasnt handled by module load-info. I never saw any misbehavior loading i915.ko into a vm, but still.. Signed-off-by: Jim Cromie <jim.cro...@gmail.com> --- include/linux/dynamic_debug.h | 4 ++-- kernel/module-internal.h | 1 + kernel/module.c | 9 ++++++--- lib/dynamic_debug.c | 12 ++++++++---- 4 files changed, 17 insertions(+), 9 deletions(-) diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h index 49fa1390d1f8..0fcbe96736f3 100644 --- a/include/linux/dynamic_debug.h +++ b/include/linux/dynamic_debug.h @@ -70,8 +70,8 @@ struct _ddebug { /* 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); +int ddebug_add_module(struct _ddebug *tab, struct _ddebug_callsite *sites, + unsigned int n, const char *modname); extern int ddebug_remove_module(const char *mod_name); extern __printf(2, 3) void __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...); diff --git a/kernel/module-internal.h b/kernel/module-internal.h index 33783abc377b..920b085d2a1b 100644 --- a/kernel/module-internal.h +++ b/kernel/module-internal.h @@ -18,6 +18,7 @@ struct load_info { char *secstrings, *strtab; unsigned long symoffs, stroffs, init_typeoffs, core_typeoffs; struct _ddebug *debug; + struct _ddebug_callsite *sites; unsigned int num_debug; bool sig_ok; #ifdef CONFIG_KALLSYMS diff --git a/kernel/module.c b/kernel/module.c index a4fa44a652a7..876765bc666a 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -2820,11 +2820,12 @@ static void add_kallsyms(struct module *mod, const struct load_info *info) } #endif /* CONFIG_KALLSYMS */ -static void dynamic_debug_setup(struct module *mod, struct _ddebug *debug, unsigned int num) +static void dynamic_debug_setup(struct module *mod, struct _ddebug *debug, + struct _ddebug_callsite *sites, unsigned int num) { if (!debug) return; - ddebug_add_module(debug, num, mod->name); + ddebug_add_module(debug, sites, num, mod->name); } static void dynamic_debug_remove(struct module *mod, struct _ddebug *debug) @@ -3299,6 +3300,8 @@ static int find_module_sections(struct module *mod, struct load_info *info) info->debug = section_objs(info, "__dyndbg", sizeof(*info->debug), &info->num_debug); + info->sites = section_objs(info, "__dyndbg_callsites", + sizeof(*info->sites), &info->num_debug); return 0; } @@ -3937,7 +3940,7 @@ static int load_module(struct load_info *info, const char __user *uargs, goto free_arch_cleanup; } - dynamic_debug_setup(mod, info->debug, info->num_debug); + dynamic_debug_setup(mod, info->debug, info->sites, info->num_debug); /* Ftrace init must be called in the MODULE_STATE_UNFORMED state */ ftrace_module_init(mod); diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index c1a113460637..8ad9be28f38e 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -49,6 +49,7 @@ struct ddebug_table { const char *mod_name; unsigned int num_ddebugs; struct _ddebug *ddebugs; + struct _ddebug_callsite *sites; }; struct ddebug_query { @@ -1014,8 +1015,8 @@ static const struct proc_ops proc_fops = { * Allocate a new ddebug_table for the given module * and add it to the global list. */ -int ddebug_add_module(struct _ddebug *tab, unsigned int n, - const char *name) +int ddebug_add_module(struct _ddebug *tab, struct _ddebug_callsite *sites, + unsigned int n, const char *name) { struct ddebug_table *dt; @@ -1033,6 +1034,7 @@ int ddebug_add_module(struct _ddebug *tab, unsigned int n, dt->mod_name = name; dt->num_ddebugs = n; dt->ddebugs = tab; + dt->sites = sites; mutex_lock(&ddebug_lock); list_add(&dt->link, &ddebug_tables); @@ -1182,7 +1184,9 @@ static int __init dynamic_debug_init(void) if (strcmp(modname, iter->site->modname)) { modct++; - ret = ddebug_add_module(iter_mod_start, n, modname); + + ret = ddebug_add_module(iter_mod_start, site_mod_start, + n, modname); if (ret) goto out_err; n = 0; @@ -1192,7 +1196,7 @@ static int __init dynamic_debug_init(void) } n++; } - ret = ddebug_add_module(iter_mod_start, n, modname); + ret = ddebug_add_module(iter_mod_start, site_mod_start, n, modname); if (ret) goto out_err; -- 2.29.2