From: Jonathan Brassow Date: Thu, 7 Mar 2013 22:24:26 +0000 (-0600) Subject: MD: Prevent sysfs operations on uninitialized kobjects X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=90584fc93d461520a888f691144f0879283b3624;p=sagit-ice-cold%2Fkernel_xiaomi_msm8998.git MD: Prevent sysfs operations on uninitialized kobjects MD: Prevent sysfs operations on uninitialized kobjects Device-mapper does not use sysfs; but when device-mapper is leveraging MD's RAID personalities, MD sometimes attempts to update sysfs. This patch adds checks for 'mddev-kobj.sd' in sysfs_[un]link_rdev to ensure it is about to operate on something valid. This patch also checks for 'mddev->kobj.sd' before calling 'sysfs_notify' in 'remove_and_add_spares'. Although 'sysfs_notify' already makes this check, doing so in 'remove_and_add_spares' prevents an additional mutex operation. Signed-off-by: Jonathan Brassow Signed-off-by: NeilBrown --- diff --git a/drivers/md/md.c b/drivers/md/md.c index fcb878f88796..aeceedfc530b 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -7663,10 +7663,8 @@ static int remove_and_add_spares(struct mddev *mddev) removed++; } } - if (removed) - sysfs_notify(&mddev->kobj, NULL, - "degraded"); - + if (removed && mddev->kobj.sd) + sysfs_notify(&mddev->kobj, NULL, "degraded"); rdev_for_each(rdev, mddev) { if (rdev->raid_disk >= 0 && diff --git a/drivers/md/md.h b/drivers/md/md.h index eca59c3074ef..d90fb1a879e1 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -506,7 +506,7 @@ static inline char * mdname (struct mddev * mddev) static inline int sysfs_link_rdev(struct mddev *mddev, struct md_rdev *rdev) { char nm[20]; - if (!test_bit(Replacement, &rdev->flags)) { + if (!test_bit(Replacement, &rdev->flags) && mddev->kobj.sd) { sprintf(nm, "rd%d", rdev->raid_disk); return sysfs_create_link(&mddev->kobj, &rdev->kobj, nm); } else @@ -516,7 +516,7 @@ static inline int sysfs_link_rdev(struct mddev *mddev, struct md_rdev *rdev) static inline void sysfs_unlink_rdev(struct mddev *mddev, struct md_rdev *rdev) { char nm[20]; - if (!test_bit(Replacement, &rdev->flags)) { + if (!test_bit(Replacement, &rdev->flags) && mddev->kobj.sd) { sprintf(nm, "rd%d", rdev->raid_disk); sysfs_remove_link(&mddev->kobj, nm); }