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Commit 90584fc9 authored Mar 07, 2013 by Jonathan Brassow Committed by NeilBrown Mar 20, 2013

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 <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>

parent e3620a3a

drivers/md/md.c

+2 −4

Original line number	Diff line number	Diff line
		@@ -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 &&

drivers/md/md.h

+2 −2

Original line number	Diff line number	Diff line
		@@ -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);
		}