It seems dangerous to allow code modifications to take place concurrently with module unloading. So take the text_mutex while the memory of the module is freed. Signed-off-by: Nadav Amit <namit@xxxxxxxxxx> --- kernel/module.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/kernel/module.c b/kernel/module.c index 57c5b23746e7..b45754961143 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -64,6 +64,7 @@ #include <linux/bsearch.h> #include <linux/dynamic_debug.h> #include <linux/audit.h> +#include <linux/memory.h> #include <uapi/linux/module.h> #include "module-internal.h" @@ -2181,6 +2182,9 @@ static void free_module(struct module *mod) synchronize_sched(); mutex_unlock(&module_mutex); + /* Protect against patching of the module while it is being removed */ + mutex_lock(&text_mutex); + /* This may be empty, but that's OK */ module_restore_mappings(&mod->init_layout); module_arch_freeing_init(mod); @@ -2194,6 +2198,7 @@ static void free_module(struct module *mod) /* Finally, free the core (containing the module structure) */ module_restore_mappings(&mod->core_layout); module_memfree(mod->core_layout.base); + mutex_unlock(&text_mutex); } void *__symbol_get(const char *symbol) -- 2.17.1
