From: Nadav Amit <namit@xxxxxxxxxx> 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> Signed-off-by: Rick Edgecombe <rick.p.edgecombe@xxxxxxxxx> --- kernel/module.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/kernel/module.c b/kernel/module.c index 1af5c8e19086..90cfc4988d98 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" @@ -2157,6 +2158,9 @@ static void free_module(struct module *mod) synchronize_rcu(); 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_arch_freeing_init(mod); module_memfree(mod->init_layout.base); @@ -2168,6 +2172,7 @@ static void free_module(struct module *mod) /* Finally, free the core (containing the module structure) */ module_memfree(mod->core_layout.base); + mutex_unlock(&text_mutex); } void *__symbol_get(const char *symbol) -- 2.17.1
