From 0d515210b6969ecfc161f71a4515831d9a6e58f4 Mon Sep 17 00:00:00 2001 From: Bob Peterson Date: Wed, 13 Jun 2012 10:27:41 -0400 Subject: 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 Signed-off-by: Steven Whitehouse --- fs/gfs2/sys.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) (limited to 'fs/gfs2/sys.c') 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 @@ static struct attribute *gfs2_attrs[] = { 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 @@ int gfs2_sys_fs_add(struct gfs2_sbd *sdp) 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 @@ int gfs2_sys_fs_add(struct gfs2_sbd *sdp) 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_lock_module: 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; } -- cgit v1.1