GFS2: Add kobject release method
This patch adds a kobject release function that properly maintains
the kobject use count, so that accesses to the sysfs files do not
cause an access to freed kernel memory after an unmount.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
diff --git a/fs/gfs2/sys.c b/fs/gfs2/sys.c
index 9c2592b..e4bee4b 100644
--- a/fs/gfs2/sys.c
+++ b/fs/gfs2/sys.c
@@ -276,7 +276,15 @@
NULL,
};
+static void gfs2_sbd_release(struct kobject *kobj)
+{
+ struct gfs2_sbd *sdp = container_of(kobj, struct gfs2_sbd, sd_kobj);
+
+ kfree(sdp);
+}
+
static struct kobj_type gfs2_ktype = {
+ .release = gfs2_sbd_release,
.default_attrs = gfs2_attrs,
.sysfs_ops = &gfs2_attr_ops,
};
@@ -583,6 +591,7 @@
char ro[20];
char spectator[20];
char *envp[] = { ro, spectator, NULL };
+ int sysfs_frees_sdp = 0;
sprintf(ro, "RDONLY=%d", (sb->s_flags & MS_RDONLY) ? 1 : 0);
sprintf(spectator, "SPECTATOR=%d", sdp->sd_args.ar_spectator ? 1 : 0);
@@ -591,8 +600,10 @@
error = kobject_init_and_add(&sdp->sd_kobj, &gfs2_ktype, NULL,
"%s", sdp->sd_table_name);
if (error)
- goto fail;
+ goto fail_reg;
+ sysfs_frees_sdp = 1; /* Freeing sdp is now done by sysfs calling
+ function gfs2_sbd_release. */
error = sysfs_create_group(&sdp->sd_kobj, &tune_group);
if (error)
goto fail_reg;
@@ -615,9 +626,13 @@
fail_tune:
sysfs_remove_group(&sdp->sd_kobj, &tune_group);
fail_reg:
- kobject_put(&sdp->sd_kobj);
-fail:
+ free_percpu(sdp->sd_lkstats);
fs_err(sdp, "error %d adding sysfs files", error);
+ if (sysfs_frees_sdp)
+ kobject_put(&sdp->sd_kobj);
+ else
+ kfree(sdp);
+ sb->s_fs_info = NULL;
return error;
}