From e2691f6b44ed2135bfd005ad5fbabac4f433a7a1 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sat, 27 Aug 2022 19:04:40 -1000 Subject: cgroup: Implement cgroup_file_show() Add cgroup_file_show() which allows toggling visibility of a cgroup file using the new kernfs_show(). This will be used to hide psi interface files on cgroups where it's disabled. Cc: Chengming Zhou Cc: Johannes Weiner Tested-by: Chengming Zhou Reviewed-by: Chengming Zhou Signed-off-by: Tejun Heo Link: https://lore.kernel.org/r/20220828050440.734579-10-tj@kernel.org Signed-off-by: Greg Kroah-Hartman --- kernel/cgroup/cgroup.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'kernel') diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index ffaccd6373f1..217469a1ea29 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -4339,6 +4339,26 @@ void cgroup_file_notify(struct cgroup_file *cfile) spin_unlock_irqrestore(&cgroup_file_kn_lock, flags); } +/** + * cgroup_file_show - show or hide a hidden cgroup file + * @cfile: target cgroup_file obtained by setting cftype->file_offset + * @show: whether to show or hide + */ +void cgroup_file_show(struct cgroup_file *cfile, bool show) +{ + struct kernfs_node *kn; + + spin_lock_irq(&cgroup_file_kn_lock); + kn = cfile->kn; + kernfs_get(kn); + spin_unlock_irq(&cgroup_file_kn_lock); + + if (kn) + kernfs_show(kn, show); + + kernfs_put(kn); +} + /** * css_next_child - find the next child of a given css * @pos: the current position (%NULL to initiate traversal) -- cgit v1.2.3 From b7b4eebdba7b6aea6b34dc29691b71c39d1dbd6a Mon Sep 17 00:00:00 2001 From: Jim Cromie Date: Sun, 4 Sep 2022 15:40:48 -0600 Subject: dyndbg: gather __dyndbg[] state into struct _ddebug_info This new struct composes the linker provided (vector,len) section, and provides a place to add other __dyndbg[] state-data later: descs - the vector of descriptors in __dyndbg section. num_descs - length of the data/section. Use it, in several different ways, as follows: In lib/dynamic_debug.c: ddebug_add_module(): Alter params-list, replacing 2 args (array,index) with a struct _ddebug_info * containing them both, with room for expansion. This helps future-proof the function prototype against the looming addition of class-map info into the dyndbg-state, by providing a place to add more member fields later. NB: later add static struct _ddebug_info builtins_state declaration, not needed yet. ddebug_add_module() is called in 2 contexts: In dynamic_debug_init(), declare, init a struct _ddebug_info di auto-var to use as a cursor. Then iterate over the prdbg blocks of the builtin modules, and update the di cursor before calling _add_module for each. Its called from kernel/module/main.c:load_info() for each loaded module: In internal.h, alter struct load_info, replacing the dyndbg array,len fields with an embedded _ddebug_info containing them both; and populate its members in find_module_sections(). The 2 calling contexts differ in that _init deals with contiguous subranges of __dyndbgs[] section, packed together, while loadable modules are added one at a time. So rename ddebug_add_module() into outer/__inner fns, call __inner from _init, and provide the offset into the builtin __dyndbgs[] where the module's prdbgs reside. The cursor provides start, len of the subrange for each. The offset will be used later to pack the results of builtin __dyndbg_sites[] de-duplication, and is 0 and unneeded for loadable modules, Note: kernel/module/main.c includes for struct _ddeubg_info. This might be prone to include loops, since its also included by printk.h. Nothing has broken in robot-land on this. cc: Luis Chamberlain Signed-off-by: Jim Cromie Link: https://lore.kernel.org/r/20220904214134.408619-12-jim.cromie@gmail.com Signed-off-by: Greg Kroah-Hartman --- include/linux/dynamic_debug.h | 13 ++++++++----- kernel/module/internal.h | 4 ++-- kernel/module/main.c | 18 +++++++++--------- lib/dynamic_debug.c | 40 +++++++++++++++++++++++++++++++--------- 4 files changed, 50 insertions(+), 25 deletions(-) (limited to 'kernel') diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h index 8d9eec5f6d8b..6a2001250da1 100644 --- a/include/linux/dynamic_debug.h +++ b/include/linux/dynamic_debug.h @@ -51,12 +51,16 @@ struct _ddebug { #endif } __attribute__((aligned(8))); - +/* encapsulate linker provided built-in (or module) dyndbg data */ +struct _ddebug_info { + struct _ddebug *descs; + unsigned int num_descs; +}; #if defined(CONFIG_DYNAMIC_DEBUG_CORE) -int ddebug_add_module(struct _ddebug *tab, unsigned int n, - const char *modname); +int ddebug_add_module(struct _ddebug_info *dyndbg, 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, ...); @@ -184,8 +188,7 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor, #include #include -static inline int ddebug_add_module(struct _ddebug *tab, unsigned int n, - const char *modname) +static inline int ddebug_add_module(struct _ddebug_info *dinfo, const char *modname) { return 0; } diff --git a/kernel/module/internal.h b/kernel/module/internal.h index 680d980a4fb2..2e2bf236f558 100644 --- a/kernel/module/internal.h +++ b/kernel/module/internal.h @@ -53,6 +53,7 @@ extern const struct kernel_symbol __stop___ksymtab_gpl[]; extern const s32 __start___kcrctab[]; extern const s32 __start___kcrctab_gpl[]; +#include struct load_info { const char *name; /* pointer to module in temporary copy, freed at end of load_module() */ @@ -62,8 +63,7 @@ struct load_info { Elf_Shdr *sechdrs; char *secstrings, *strtab; unsigned long symoffs, stroffs, init_typeoffs, core_typeoffs; - struct _ddebug *debug; - unsigned int num_debug; + struct _ddebug_info dyndbg; bool sig_ok; #ifdef CONFIG_KALLSYMS unsigned long mod_kallsyms_init_off; diff --git a/kernel/module/main.c b/kernel/module/main.c index 6a477c622544..a26b436ad992 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -1598,16 +1598,16 @@ static void free_modinfo(struct module *mod) } } -static void dynamic_debug_setup(struct module *mod, struct _ddebug *debug, unsigned int num) +static void dynamic_debug_setup(struct module *mod, struct _ddebug_info *dyndbg) { - if (!debug) + if (!dyndbg->num_descs) return; - ddebug_add_module(debug, num, mod->name); + ddebug_add_module(dyndbg, mod->name); } -static void dynamic_debug_remove(struct module *mod, struct _ddebug *debug) +static void dynamic_debug_remove(struct module *mod, struct _ddebug_info *dyndbg) { - if (debug) + if (dyndbg->num_descs) ddebug_remove_module(mod->name); } @@ -2111,8 +2111,8 @@ static int find_module_sections(struct module *mod, struct load_info *info) if (section_addr(info, "__obsparm")) pr_warn("%s: Ignoring obsolete parameters\n", mod->name); - info->debug = section_objs(info, "__dyndbg", - sizeof(*info->debug), &info->num_debug); + info->dyndbg.descs = section_objs(info, "__dyndbg", + sizeof(*info->dyndbg.descs), &info->dyndbg.num_descs); return 0; } @@ -2807,7 +2807,7 @@ static int load_module(struct load_info *info, const char __user *uargs, } init_build_id(mod, info); - dynamic_debug_setup(mod, info->debug, info->num_debug); + dynamic_debug_setup(mod, &info->dyndbg); /* Ftrace init must be called in the MODULE_STATE_UNFORMED state */ ftrace_module_init(mod); @@ -2871,7 +2871,7 @@ static int load_module(struct load_info *info, const char __user *uargs, ddebug_cleanup: ftrace_release_mod(mod); - dynamic_debug_remove(mod, info->debug); + dynamic_debug_remove(mod, &info->dyndbg); synchronize_rcu(); kfree(mod->args); free_arch_cleanup: diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index 2e8ebef3bd0d..c358ccdf4a39 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -923,14 +923,20 @@ 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) +static int __ddebug_add_module(struct _ddebug_info *di, unsigned int base, + const char *modname) { struct ddebug_table *dt; + v3pr_info("add-module: %s.%d sites\n", modname, di->num_descs); + if (!di->num_descs) { + v3pr_info(" skip %s\n", modname); + return 0; + } + dt = kzalloc(sizeof(*dt), GFP_KERNEL); if (dt == NULL) { - pr_err("error adding module: %s\n", name); + pr_err("error adding module: %s\n", modname); return -ENOMEM; } /* @@ -939,18 +945,25 @@ int ddebug_add_module(struct _ddebug *tab, unsigned int n, * member of struct module, which lives at least as long as * this struct ddebug_table. */ - dt->mod_name = name; - dt->num_ddebugs = n; - dt->ddebugs = tab; + dt->mod_name = modname; + dt->ddebugs = di->descs; + dt->num_ddebugs = di->num_descs; + + INIT_LIST_HEAD(&dt->link); mutex_lock(&ddebug_lock); list_add_tail(&dt->link, &ddebug_tables); mutex_unlock(&ddebug_lock); - vpr_info("%3u debug prints in module %s\n", n, dt->mod_name); + vpr_info("%3u debug prints in module %s\n", di->num_descs, modname); return 0; } +int ddebug_add_module(struct _ddebug_info *di, const char *modname) +{ + return __ddebug_add_module(di, 0, modname); +} + /* helper for ddebug_dyndbg_(boot|module)_param_cb */ static int ddebug_dyndbg_param_cb(char *param, char *val, const char *modname, int on_err) @@ -1064,6 +1077,11 @@ static int __init dynamic_debug_init(void) const char *modname; char *cmdline; + struct _ddebug_info di = { + .descs = __start___dyndbg, + .num_descs = __stop___dyndbg - __start___dyndbg, + }; + if (&__start___dyndbg == &__stop___dyndbg) { if (IS_ENABLED(CONFIG_DYNAMIC_DEBUG)) { pr_warn("_ddebug table is empty in a CONFIG_DYNAMIC_DEBUG build\n"); @@ -1082,7 +1100,9 @@ static int __init dynamic_debug_init(void) if (strcmp(modname, iter->modname)) { mod_ct++; - ret = ddebug_add_module(iter_mod_start, mod_sites, modname); + di.num_descs = mod_sites; + di.descs = iter_mod_start; + ret = __ddebug_add_module(&di, i - mod_sites, modname); if (ret) goto out_err; @@ -1091,7 +1111,9 @@ static int __init dynamic_debug_init(void) iter_mod_start = iter; } } - ret = ddebug_add_module(iter_mod_start, mod_sites, modname); + di.num_descs = mod_sites; + di.descs = iter_mod_start; + ret = __ddebug_add_module(&di, i - mod_sites, modname); if (ret) goto out_err; -- cgit v1.2.3 From 66f4006b6ace1a1a1a1dca4225972f79a298e251 Mon Sep 17 00:00:00 2001 From: Jim Cromie Date: Sun, 4 Sep 2022 15:40:52 -0600 Subject: kernel/module: add __dyndbg_classes section Add __dyndbg_classes section, using __dyndbg as a model. Use it: vmlinux.lds.h: KEEP the new section, which also silences orphan section warning on loadable modules. Add (__start_/__stop_)__dyndbg_classes linker symbols for the c externs (below). kernel/module/main.c: - fill new fields in find_module_sections(), using section_objs() - extend callchain prototypes to pass classes, length load_module(): pass new info to dynamic_debug_setup() dynamic_debug_setup(): new params, pass through to ddebug_add_module() dynamic_debug.c: - add externs to the linker symbols. ddebug_add_module(): - It currently builds a debug_table, and *will* find and attach classes. dynamic_debug_init(): - add class fields to the _ddebug_info cursor var: di. Signed-off-by: Jim Cromie Link: https://lore.kernel.org/r/20220904214134.408619-16-jim.cromie@gmail.com Signed-off-by: Greg Kroah-Hartman --- include/asm-generic/vmlinux.lds.h | 3 +++ include/linux/dynamic_debug.h | 2 ++ kernel/module/main.c | 2 ++ lib/dynamic_debug.c | 7 +++++++ 4 files changed, 14 insertions(+) (limited to 'kernel') diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 7515a465ec03..9b8bd5504ad9 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -345,6 +345,9 @@ *(__tracepoints) \ /* implement dynamic printk debug */ \ . = ALIGN(8); \ + __start___dyndbg_classes = .; \ + KEEP(*(__dyndbg_classes)) \ + __stop___dyndbg_classes = .; \ __start___dyndbg = .; \ KEEP(*(__dyndbg)) \ __stop___dyndbg = .; \ diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h index 98dbf1d49984..9073a43a2039 100644 --- a/include/linux/dynamic_debug.h +++ b/include/linux/dynamic_debug.h @@ -114,7 +114,9 @@ struct ddebug_class_map { /* encapsulate linker provided built-in (or module) dyndbg data */ struct _ddebug_info { struct _ddebug *descs; + struct ddebug_class_map *classes; unsigned int num_descs; + unsigned int num_classes; }; #if defined(CONFIG_DYNAMIC_DEBUG_CORE) diff --git a/kernel/module/main.c b/kernel/module/main.c index a26b436ad992..00641d1022a5 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -2113,6 +2113,8 @@ static int find_module_sections(struct module *mod, struct load_info *info) info->dyndbg.descs = section_objs(info, "__dyndbg", sizeof(*info->dyndbg.descs), &info->dyndbg.num_descs); + info->dyndbg.classes = section_objs(info, "__dyndbg_classes", + sizeof(*info->dyndbg.classes), &info->dyndbg.num_classes); return 0; } diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index c358ccdf4a39..fb31a1a2fc3f 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -41,6 +41,8 @@ extern struct _ddebug __start___dyndbg[]; extern struct _ddebug __stop___dyndbg[]; +extern struct ddebug_class_map __start___dyndbg_classes[]; +extern struct ddebug_class_map __stop___dyndbg_classes[]; struct ddebug_table { struct list_head link; @@ -1079,7 +1081,9 @@ static int __init dynamic_debug_init(void) struct _ddebug_info di = { .descs = __start___dyndbg, + .classes = __start___dyndbg_classes, .num_descs = __stop___dyndbg - __start___dyndbg, + .num_classes = __stop___dyndbg_classes - __start___dyndbg_classes, }; if (&__start___dyndbg == &__stop___dyndbg) { @@ -1122,6 +1126,9 @@ static int __init dynamic_debug_init(void) i, mod_ct, (int)((mod_ct * sizeof(struct ddebug_table)) >> 10), (int)((i * sizeof(struct _ddebug)) >> 10)); + if (di.num_classes) + v2pr_info(" %d builtin ddebug class-maps\n", di.num_classes); + /* now that ddebug tables are loaded, process all boot args * again to find and activate queries given in dyndbg params. * While this has already been done for known boot params, it -- cgit v1.2.3