[PATCH 5/8] module: introduce MODULE_STATE_GONE

From: "Mike Rapoport (Microsoft)" rppt@kernel.org

In order to use execmem's API for temporal remapping of the memory allocated from ROX cache as writable, there is a need to distinguish between the state when the module is being formed and the state when it is deconstructed and freed so that when module_memory_free() is called from error paths during module loading it could restore ROX mappings.

Replace open coded checks for MODULE_STATE_UNFORMED with a helper function module_is_formed() and add a new MODULE_STATE_GONE that will be set when the module is deconstructed and freed.

Signed-off-by: Mike Rapoport (Microsoft) rppt@kernel.org --- include/linux/module.h | 6 ++++++ kernel/module/kallsyms.c | 8 ++++---- kernel/module/kdb.c | 2 +- kernel/module/main.c | 19 +++++++++---------- kernel/module/procfs.c | 2 +- kernel/tracepoint.c | 2 ++ lib/kunit/test.c | 2 ++ samples/livepatch/livepatch-callbacks-demo.c | 1 + .../test_modules/test_klp_callbacks_demo.c | 1 + .../test_modules/test_klp_callbacks_demo2.c | 1 + .../livepatch/test_modules/test_klp_state.c | 1 + .../livepatch/test_modules/test_klp_state2.c | 1 + 12 files changed, 30 insertions(+), 16 deletions(-)

diff --git a/include/linux/module.h b/include/linux/module.h index 94acbacdcdf1..bd8cf93d32c8 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -320,6 +320,7 @@ enum module_state { MODULE_STATE_COMING, /* Full formed, running module_init. */ MODULE_STATE_GOING, /* Going away. */ MODULE_STATE_UNFORMED, /* Still setting it up. */ + MODULE_STATE_GONE, /* Deconstructing and freeing. */ };

struct mod_tree_node { @@ -620,6 +621,11 @@ static inline bool module_is_coming(struct module *mod) return mod->state == MODULE_STATE_COMING; }

+static inline bool module_is_formed(struct module *mod) +{ + return mod->state < MODULE_STATE_UNFORMED; +} + struct module *__module_text_address(unsigned long addr); struct module *__module_address(unsigned long addr); bool is_module_address(unsigned long addr); diff --git a/kernel/module/kallsyms.c b/kernel/module/kallsyms.c index bf65e0c3c86f..daf9a9b3740f 100644 --- a/kernel/module/kallsyms.c +++ b/kernel/module/kallsyms.c @@ -361,7 +361,7 @@ int lookup_module_symbol_name(unsigned long addr, char *symname)

preempt_disable(); list_for_each_entry_rcu(mod, &modules, list) { - if (mod->state == MODULE_STATE_UNFORMED) + if (!module_is_formed(mod)) continue; if (within_module(addr, mod)) { const char *sym; @@ -389,7 +389,7 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type, list_for_each_entry_rcu(mod, &modules, list) { struct mod_kallsyms *kallsyms;

- if (mod->state == MODULE_STATE_UNFORMED) + if (!module_is_formed(mod)) continue; kallsyms = rcu_dereference_sched(mod->kallsyms); if (symnum < kallsyms->num_symtab) { @@ -441,7 +441,7 @@ static unsigned long __module_kallsyms_lookup_name(const char *name) list_for_each_entry_rcu(mod, &modules, list) { unsigned long ret;

- if (mod->state == MODULE_STATE_UNFORMED) + if (!module_is_formed(mod)) continue; ret = __find_kallsyms_symbol_value(mod, name); if (ret) @@ -484,7 +484,7 @@ int module_kallsyms_on_each_symbol(const char *modname, list_for_each_entry(mod, &modules, list) { struct mod_kallsyms *kallsyms;

- if (mod->state == MODULE_STATE_UNFORMED) + if (!module_is_formed(mod)) continue;

if (modname && strcmp(modname, mod->name)) diff --git a/kernel/module/kdb.c b/kernel/module/kdb.c index 995c32d3698f..14f14700ffc2 100644 --- a/kernel/module/kdb.c +++ b/kernel/module/kdb.c @@ -23,7 +23,7 @@ int kdb_lsmod(int argc, const char **argv)

kdb_printf("Module Size modstruct Used by\n"); list_for_each_entry(mod, &modules, list) { - if (mod->state == MODULE_STATE_UNFORMED) + if (!module_is_formed(mod)) continue;

kdb_printf("%-20s%8u", mod->name, mod->mem[MOD_TEXT].size); diff --git a/kernel/module/main.c b/kernel/module/main.c index 5399c182b3cb..ad8ef20c120f 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -153,7 +153,7 @@ EXPORT_SYMBOL(unregister_module_notifier); */ static inline int strong_try_module_get(struct module *mod) { - BUG_ON(mod && mod->state == MODULE_STATE_UNFORMED); + BUG_ON(mod && !module_is_formed(mod)); if (mod && mod->state == MODULE_STATE_COMING) return -EBUSY; if (try_module_get(mod)) @@ -361,7 +361,7 @@ bool find_symbol(struct find_symbol_arg *fsa) GPL_ONLY }, };

- if (mod->state == MODULE_STATE_UNFORMED) + if (!module_is_formed(mod)) continue;

for (i = 0; i < ARRAY_SIZE(arr); i++) @@ -386,7 +386,7 @@ struct module *find_module_all(const char *name, size_t len,

list_for_each_entry_rcu(mod, &modules, list, lockdep_is_held(&module_mutex)) { - if (!even_unformed && mod->state == MODULE_STATE_UNFORMED) + if (!even_unformed && !module_is_formed(mod)) continue; if (strlen(mod->name) == len && !memcmp(mod->name, name, len)) return mod; @@ -457,7 +457,7 @@ bool __is_module_percpu_address(unsigned long addr, unsigned long *can_addr) preempt_disable();

list_for_each_entry_rcu(mod, &modules, list) { - if (mod->state == MODULE_STATE_UNFORMED) + if (!module_is_formed(mod)) continue; if (!mod->percpu_size) continue; @@ -1326,7 +1326,7 @@ static void free_module(struct module *mod) * that noone uses it while it's being deconstructed. */ mutex_lock(&module_mutex); - mod->state = MODULE_STATE_UNFORMED; + mod->state = MODULE_STATE_GONE; mutex_unlock(&module_mutex);

/* Arch-specific cleanup. */ @@ -3048,8 +3048,7 @@ static int module_patient_check_exists(const char *name, if (old == NULL) return 0;

- if (old->state == MODULE_STATE_COMING || - old->state == MODULE_STATE_UNFORMED) { + if (old->state == MODULE_STATE_COMING || !module_is_formed(old)) { /* Wait in case it fails to load. */ mutex_unlock(&module_mutex); err = wait_event_interruptible(module_wq, @@ -3608,7 +3607,7 @@ char *module_flags(struct module *mod, char *buf, bool show_state) { int bx = 0;

- BUG_ON(mod->state == MODULE_STATE_UNFORMED); + BUG_ON(!module_is_formed(mod)); if (!mod->taints && !show_state) goto out; if (mod->taints || @@ -3702,7 +3701,7 @@ struct module *__module_address(unsigned long addr) mod = mod_find(addr, &mod_tree); if (mod) { BUG_ON(!within_module(addr, mod)); - if (mod->state == MODULE_STATE_UNFORMED) + if (!module_is_formed(mod)) mod = NULL; } return mod; @@ -3756,7 +3755,7 @@ void print_modules(void) /* Most callers should already have preempt disabled, but make sure */ preempt_disable(); list_for_each_entry_rcu(mod, &modules, list) { - if (mod->state == MODULE_STATE_UNFORMED) + if (!module_is_formed(mod)) continue; pr_cont(" %s%s", mod->name, module_flags(mod, buf, true)); } diff --git a/kernel/module/procfs.c b/kernel/module/procfs.c index 0a4841e88adb..2c617e6f8bc0 100644 --- a/kernel/module/procfs.c +++ b/kernel/module/procfs.c @@ -79,7 +79,7 @@ static int m_show(struct seq_file *m, void *p) unsigned int size;

/* We always ignore unformed modules. */ - if (mod->state == MODULE_STATE_UNFORMED) + if (!module_is_formed(mod)) return 0;

size = module_total_size(mod); diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c index 1848ce7e2976..e94247afb2c6 100644 --- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c @@ -668,6 +668,8 @@ static int tracepoint_module_notify(struct notifier_block *self, break; case MODULE_STATE_UNFORMED: break; + case MODULE_STATE_GONE: + break; } return notifier_from_errno(ret); } diff --git a/lib/kunit/test.c b/lib/kunit/test.c index 089c832e3cdb..54eaed92a2d3 100644 --- a/lib/kunit/test.c +++ b/lib/kunit/test.c @@ -836,6 +836,8 @@ static int kunit_module_notify(struct notifier_block *nb, unsigned long val, break; case MODULE_STATE_UNFORMED: break; + case MODULE_STATE_GONE: + break; }

return 0; diff --git a/samples/livepatch/livepatch-callbacks-demo.c b/samples/livepatch/livepatch-callbacks-demo.c index 11c3f4357812..324bddaef9a6 100644 --- a/samples/livepatch/livepatch-callbacks-demo.c +++ b/samples/livepatch/livepatch-callbacks-demo.c @@ -93,6 +93,7 @@ static const char *const module_state[] = { [MODULE_STATE_COMING] = "[MODULE_STATE_COMING] Full formed, running module_init", [MODULE_STATE_GOING] = "[MODULE_STATE_GOING] Going away", [MODULE_STATE_UNFORMED] = "[MODULE_STATE_UNFORMED] Still setting it up", + [MODULE_STATE_GONE] = "[MODULE_STATE_GONE] Deconstructing and freeing", };

static void callback_info(const char *callback, struct klp_object *obj) diff --git a/tools/testing/selftests/livepatch/test_modules/test_klp_callbacks_demo.c b/tools/testing/selftests/livepatch/test_modules/test_klp_callbacks_demo.c index 3fd8fe1cd1cc..8435e3254f85 100644 --- a/tools/testing/selftests/livepatch/test_modules/test_klp_callbacks_demo.c +++ b/tools/testing/selftests/livepatch/test_modules/test_klp_callbacks_demo.c @@ -16,6 +16,7 @@ static const char *const module_state[] = { [MODULE_STATE_COMING] = "[MODULE_STATE_COMING] Full formed, running module_init", [MODULE_STATE_GOING] = "[MODULE_STATE_GOING] Going away", [MODULE_STATE_UNFORMED] = "[MODULE_STATE_UNFORMED] Still setting it up", + [MODULE_STATE_GONE] = "[MODULE_STATE_GONE] Deconstructing and freeing", };

static void callback_info(const char *callback, struct klp_object *obj) diff --git a/tools/testing/selftests/livepatch/test_modules/test_klp_callbacks_demo2.c b/tools/testing/selftests/livepatch/test_modules/test_klp_callbacks_demo2.c index 5417573e80af..78c1fff5d977 100644 --- a/tools/testing/selftests/livepatch/test_modules/test_klp_callbacks_demo2.c +++ b/tools/testing/selftests/livepatch/test_modules/test_klp_callbacks_demo2.c @@ -16,6 +16,7 @@ static const char *const module_state[] = { [MODULE_STATE_COMING] = "[MODULE_STATE_COMING] Full formed, running module_init", [MODULE_STATE_GOING] = "[MODULE_STATE_GOING] Going away", [MODULE_STATE_UNFORMED] = "[MODULE_STATE_UNFORMED] Still setting it up", + [MODULE_STATE_GONE] = "[MODULE_STATE_GONE] Deconstructing and freeing", };

static void callback_info(const char *callback, struct klp_object *obj) diff --git a/tools/testing/selftests/livepatch/test_modules/test_klp_state.c b/tools/testing/selftests/livepatch/test_modules/test_klp_state.c index 57a4253acb01..bdebf1d24c98 100644 --- a/tools/testing/selftests/livepatch/test_modules/test_klp_state.c +++ b/tools/testing/selftests/livepatch/test_modules/test_klp_state.c @@ -18,6 +18,7 @@ static const char *const module_state[] = { [MODULE_STATE_COMING] = "[MODULE_STATE_COMING] Full formed, running module_init", [MODULE_STATE_GOING] = "[MODULE_STATE_GOING] Going away", [MODULE_STATE_UNFORMED] = "[MODULE_STATE_UNFORMED] Still setting it up", + [MODULE_STATE_GONE] = "[MODULE_STATE_GONE] Deconstructing and freeing", };

static void callback_info(const char *callback, struct klp_object *obj) diff --git a/tools/testing/selftests/livepatch/test_modules/test_klp_state2.c b/tools/testing/selftests/livepatch/test_modules/test_klp_state2.c index c978ea4d5e67..1a55f84a8eb3 100644 --- a/tools/testing/selftests/livepatch/test_modules/test_klp_state2.c +++ b/tools/testing/selftests/livepatch/test_modules/test_klp_state2.c @@ -18,6 +18,7 @@ static const char *const module_state[] = { [MODULE_STATE_COMING] = "[MODULE_STATE_COMING] Full formed, running module_init", [MODULE_STATE_GOING] = "[MODULE_STATE_GOING] Going away", [MODULE_STATE_UNFORMED] = "[MODULE_STATE_UNFORMED] Still setting it up", + [MODULE_STATE_GONE] = "[MODULE_STATE_GONE] Deconstructing and freeing", };

static void callback_info(const char *callback, struct klp_object *obj)