pstore/platform: Switch pstore_info::name to const

In order to more cleanly pass around backend names, make the "name" member
const. This means the module param needs to be dynamic (technically, it
was before, so this actually cleans up a minor memory leak if a backend
was specified and then gets unloaded.)

Link: https://lore.kernel.org/lkml/20200510202436.63222-3-keescook@chromium.org/
Signed-off-by: Kees Cook <keescook@chromium.org>

diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 8beaeff723863d821982280ab5829921a337ab38..715396bef0eaba46731173a414bbf85d49502e18 100644 (file)
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -624,7 +624,7 @@ int pstore_register(struct pstore_info *psi)
         * Update the module parameter backend, so it is visible
         * through /sys/module/pstore/parameters/backend
         */
-       backend = psi->name;
+       backend = kstrdup(psi->name, GFP_KERNEL);
 
        pr_info("Registered %s as persistent store backend\n", psi->name);
 
@@ -667,6 +667,7 @@ void pstore_unregister(struct pstore_info *psi)
        free_buf_for_compression();
 
        psinfo = NULL;
+       kfree(backend);
        backend = NULL;
        mutex_unlock(&psinfo_lock);
 }

diff --git a/include/linux/pstore.h b/include/linux/pstore.h
index e779441e6d26cbaa576abe7f4f89d11e91bbaa19..f6f22b13e04fc0c3f7ad86b68e1c3d9378058631 100644 (file)
--- a/include/linux/pstore.h
+++ b/include/linux/pstore.h
@@ -170,7 +170,7 @@ struct pstore_record {
  */
 struct pstore_info {
        struct module   *owner;
-       char            *name;
+       const char      *name;
 
        struct semaphore buf_lock;
        char            *buf;